Fuel Transfer/Polishing System

[MOJO]

We've been using the Gulf Coast F1 paper towel filter for 15 years (3,000+ hrs) on MOJO. Can't say enough good things about it! Fuel stays clear and bright pink, and no need for Bio-Bor, etc. We use a 12v Walbro pump. One word of caution - Gulf Coast say your flow rate should not exceed 120 gph (2 gpm). I let mine run 24 hrs on each of our 4 tanks once a year, and filter fuel through the Gulf Coast filter whenever the engine is running (200-300 hrs/yr) The paper towel filter gets changed every couple of years whether it needs it or not.

There's a picture of our setup on our web site, www.mvmojo.com. It's the last picture in the "mechanical tour" page - http://www.mvmojo.com/mvmojo/MOJO%20mechanical%20tour.pdf

 

[Sailor of Fortune]

Assuming one has a common point of pickup for all tanks, and as you suggest, the total volume being stored gets consumed at least annually, then a polishing system isn't needed. However, if you have to transfer fuel from tank to tank, then you have everything already in place for fuel polishing except perhaps filters. In Delfin's case, I have 7 tanks, including 2 day tanks, so I have to have a supply and destination manifold to move fuel from any tank to the day tank or other tanks for ballasting, plus a motor to move fuel. Stick a filter on the suction side of the pump and, voila, a fuel polishing system.

So one way to look at it is that if you do have to move fuel around the boat, for the cost of a filter why would you not have a polishing system? If you don't need to move fuel, then you likely have relatively small tanks and with decent drain points why would you want polishing?

I've always thought fuel polishing on most boats is an unnecessary complication. I do agree with Delfin if you have to move fuel, you may as well filter it. On a single or 2 tank setup, I remain unconvinced as to the need. Clean tanks, access ports, and regular monitoring are far superior in my opinion.

 

[Delfin]

I've always thought fuel polishing on most boats is an unnecessary complication. I do agree with Delfin if you have to move fuel, you may as well filter it. On a single or 2 tank setup, I remain unconvinced as to the need. Clean tanks, access ports, and regular monitoring are far superior in my opinion.

And, if you are going to polish, do so when the tanks are almost empty and while slogging along in a bit of a sea since that is when whatever gunk there is will be filterable.

I just had to replace a gasket on one of my 750 gallon wing tanks. I moved the fuel remaining to other tanks, removed the inspection port (18" x 26") and inspected. After 15 years, the amount of fuel with crud in it could have fit into a quart jar, otherwise the tank was spotless, the metal bright. No hard or gunky deposits of any kind, and no water. I have drains for these tanks, but because of their awkward position have never used them, only polished occasionally while underway. The crud collected was asphaltene, I guess, and sat suspended in a glob in the lowest part of the tank, so I just sucked it up with a end of life wet/dry vac. I expected to see more crud, but the tanks were really, really clean.


By the way, your avatar shows your name as Jack (Steve?), which must mean you are going through an identity crisis. If so, I have a poem for you...Roses are red, violets are blue, I'm schizophrenic and so am I

 

[Sailor of Fortune]

Lol, Jack /Steve is a reference to TF Florida get together a year and a half ago. Not that there were any drinks involved.... Baker later referred to me as Steve,after two days of partying with him at get together. We are not a group to let things go.... SOOO Other TF members started calling me Steve.... No ball busters in this group!. Baker repented at last get together.... Now ask Al(Fly wright)about Air B and B in the Barrio!.....got to say, we had fun and it was clean...just looked like a porn set from the 70's! Not saying Al was a porn star in 70's...Maybe 80"s?

 

[83GB]

couple of comments: I have a Gulf Coast F-1 filter and a 12 volt Walbro pump. When I installed it, I plumbed into the existing fuel supply and return lines (which on my 42 GB are small). All works very well but the flow is low; the pump sort of "clickes" once or twice a second but I hear fuel falling back into the tanks. So use large enough flow lines. I also put in a lot of valving allowing me to move fuel around and to also use the Walbro as a lift pump should my on-engine pump go out ; In an emergency I can also bypass the racor filters to my twin engines should they clog. Finally, NEVER let the paper towel filter get "dirty" all the way to the top. I did that once and found the Walbro stopped working... turns out there is a fine screen filter in the Walbro that was completely clogged with black sentiment.

 

[Justtls]

Old fuel

I have an inefficient home-built fuel polishing system that allows me to pull fuel from and return it to any of the three fuel tanks. Each morning, I filter some fuel from the saddle tanks and pump it to the aft centerline tank—which I use as a day tank. That fuel goes through the usual primary Racor 500 (10 micron) and secondary NAPAs (currently also 10 microns but rethinking these) on each Lehman.

The aft tank was cleaned and I inspected it recently but the Racors still load up more than I think they should—probably in 80 to 100 hours. I think the home-made paper towel polishing filter is the culprit. I plan to replace it with a Gulf Coast F1 filter and, while I’m at it, install a new transfer pump.

What’s the consensus on the GC F1? Worth the exhorbitant cost? I’ve seen Walbro and Oberdorfer fuel pumps recommended for this. Walbro seems to have a lot of models with very little difference between them—the biggest of which moves about 43 gallons per hour. I’d like to move more like 50 gallons in 30 minutes to reduce transfer time while keeping the pump at 12 volts. Any thoughts?

O just went through a similar problem, unfortunately draining the water won't fix the problem. You probably have islands of microbes floating in your fuel. The only thing you can do is pump out each tank, clean them and filter what's leftover back through a polisher or just dispose of it.

 

[Delfin]

Lol, Jack /Steve is a reference to TF Florida get together a year and a half ago. Not that there were any drinks involved.... Baker later referred to me as Steve,after two days of partying with him at get together. We are not a group to let things go.... SOOO Other TF members started calling me Steve.... No ball busters in this group!. Baker repented at last get together.... Now ask Al(Fly wright)about Air B and B in the Barrio!.....got to say, we had fun and it was clean...just looked like a porn set from the 70's! Not saying Al was a porn star in 70's...Maybe 80"s?

Sounds like a great get together! I obviously live on the wrong coast
...

 

[Lioness]

Fuel polishing

I use a Reverso pump (150 gph) with a Gulf Coast filter. It’s been flawless for 4+ years. It’s a 12V system, I polish about 2,000 gallons a year and I replace th GC filter once a year. I also replace the Racor filters once per year, but that seems unnecessary as they are very clean. My boat is a 1991 DeFever 49, Perkins engines and 1,000 gallons of fuel in 4 tanks, no day tank. I keep the tanks full as much as possible. I hope this helps. Good luck

 

[dhays]

I have a fuel transfer pump that I use to move fuel from one side to the other for balance. I also use it if I'm just lazy. I will sometimes pump fuel to the port tank, then fill the starboard tank and avoid needed to haul the fuel hose across the cockpit.


Anyway, I've considered putting a filter in the transfer line. That line is near the bottom of both tanks so would do pretty well. However, I've never had a fuel problem, my engine returns a LOT of fuel back to the tank and my primary filters have never shown any increase in vacuum. I change the filters just because the media gets old, not because they are dirty. So while it would be relatively easy to add another filter, I haven't had any reason to need it.

 

[DaveGibson]

The best I know of is the Filter Boss system.

And get the remote filter switch for your helm station.

It solved all of my old trawler's problems.

https://trawlerdriftaway.blogspot.com/search?q=fuel+filter+system

 

[greatpapabear]

Hi Guys and Guyesses,

Without wanting to create a storm (!) may i add my two-pennyworth to the debate?

Fuel polishing has been a key subject of debate for year upon year, but I believe it's something which is not fully understood. There are the two key elements to polishing. First, to keep the fuel dust free, the second to ensure that anything which has built up at the base of the tanks (typically water, dead bug and debris) has been removed.

The first is best achieved by the overspill of fuel being drawn by the engines and returned to the tanks. This fuel will have been through at least two sets of filters and will continue being cycled for as long as the engines are turning.

The second is only achieved by a properly installed polishing system, comprising a competent filtration system and a really powerful pump. The return pipe from the pump should be aimed such that the outflow is directed at the base of the tank to stir up whatever may be lurking there. The draw should be 'somewhere' mid-tank', sucking out the now mucky fuel before passing it through the filtration system and returning it, cleaned (polished), to the return.

There a number of polishing systems on the market, but if they are not plumbed in to achieve the above, and if the pump and filtration system are not man enough, they will almost certainly only achieve that which your engines do. No more.

 

[Whodgins]

Great thread and my thanks to all who have contributed their experiences and suggestions. Just wanted to add my two thumbs up based on my experiences with a Gulf Coast Filter with a Walbro pump on a timer switch. I installed this setup on my previous boat a 52' steel Bruce Roberts design sailboat with a 6cyl Cummins and it worked flawlessly throughout the ten years I ran it while making my way about half way around the world. I did replace the Walbro once and always carried a new one onboard for backup as I tended to be in extremely remote locations and out on very long passages where I needed to be sure I could always keep my Cummins running well when needed. I still ran my fuel through a Racor 900 filter and then the spin on filter on the Cummins for added filtration and redundancy, but these filters were almost always clean and white and I only replaced them due to time and amount of fuel having passed through rather than from being dirty or clogged. I never used any fuel additives as I found it is better to prevent water and contaminants from getting into the fuel in the first place and to have a great polishing system to deal with situations when you do get dirty fuel or water. Just before I sold the boat I removed the inspection plates on both 250 USG steel tanks and there was barely any sediment and no water in the bottom of these tanks after over 10 years and thousands of gallons of fuel going through them so I was very pleased with the performance of my fuel system.

I originally bought new filters direct from GCF and kept plenty onboard and they were reasonably priced, about US$15 as I recall. However I realized that these filters were just a roll of good quality full size paper towels wrapped in a nice cloth sock and so I started to save these socks with each filter change, washed them out and then used them to cover a roll of paper towel and make my own filters this way. Certainly some savings over time but the bigger advantage for me was to not have to deal with shipping the large boxes of 6 filters to remote locations and just keep a good supply of good quality and proper sized rolls of paper towels which were much easier to find locally in most ports of call. One word of caution if you decide to go this route, you need to be sure that the paper towel rolls you buy are “full size” and good quality so that they are the right size and fit snug in the GCF housing with good end sealing. I found that there is quite a range of different sizes in different parts of the world so I would stock up when I found a supply of the right size rolls.

I also installed the same GCF setup, though different canister, as an add on bypass oil filter for my Cummins and this worked equally as well. In addition to much better oil filtration and engine life it was very helpful to be able to use the same filters for fuel and oil. It is also worth noting that as I understand it these GCF are “edge filters” meaning that the fuel/oil travels the full length of the filter cartridge/paper towel roll rather than being pushed perpendicular through the paper filter and thus being able to remove much more and much smaller contaminants.

We are now in the process of building a new boat and switching over to power for some new adventures and challenges as we continue to sail the world and she will be an all aluminium 24m eXtreme eXploration Passage Maker with a very slender and efficient LDL hull. Our main engine is a Gardner 6LXB and I would have put the same GCF system in the new boat but I lucked into a tremendous deal on a Alpha Laval MIB303 centrifuge and so I’m going with that instead. Overkill to some I’m sure but given the extremely remote locations we most often head for this should give me an extremely reliable fuel filtering and polishing system that will ensure we always have super clean fuel onboard no matter where we are in the world to feed our mighty Gardner.

For those interested in more details of the new boat build I try to put up a weekly progress update on our Mobius.World blog with lots of photos, video and explanations of our design and build process so far.

Thanks again for this great thread and many others I’ve learned from,

Wayne

 

[greatpapabear]

An Alpha Laval MIB303 centrifuge? That's the tops.

Thanks for the post. Really illuminating and interesting. I trust the new venture will exceed your dreams.

 

[sunchaser]

Who
I trust your new build will have a properly designed fuel tank pickup system for polishing along the lines as Papa mentioned. The AL can only clean the fuel it sees. Will your vessel have a day tank feeding the engine after passing through the AL? The day tank setup on most Nordhavns is a good model. A few low hour Nordhavns have suffered fouled tanks from lack of use resulting in buggy fuel though. Constant turnover of fuel dock clean product seems a great avoidance procedure, possibly the best.

 

[Bigsfish]

Post 34

Jack (Steve) you have a great remembering of that fateful evening in February when you received your alter ego name, and that surprises me after your consumption of various beers (even PBR) which we found out the next year you prefer Bud. What a screwed up world we live in. Which leads me to think how will this party, February 2019, corrupt my mind?

I hope the women keep their clothes on and leave the men alone so we can talk and contemplate the boating worlds problems this year.

 

[Whodgins]

An Alpha Laval MIB303 centrifuge? That's the tops.

Thanks for the post. Really illuminating and interesting. I trust the new venture will exceed your dreams.

Thanks for the kind wishes Papa Bear, we are having a blast for the past 3 years designing and now building our new boat and will do so even more once we launch which we hope to be by end of next year. The Alfa Laval was a great stroke of synchronicity and I couldn't be more delighted to be able to build such a fabulous fuel polishing system around it on the new boat and be able to have clean clear fuel at all times in all places.

 

[Whodgins]

Who
I trust your new build will have a properly designed fuel tank pickup system for polishing along the lines as Papa mentioned. The AL can only clean the fuel it sees. Will your vessel have a day tank feeding the engine after passing through the AL? The day tank setup on most Nordhavns is a good model. A few low hour Nordhavns have suffered fouled tanks from lack of use resulting in buggy fuel though. Constant turnover of fuel dock clean product seems a great avoidance procedure, possibly the best.

Thanks for the thoughtful suggestions and questions Sunchaser. I think we have designed a very effective setup on all our fuel tanks on the new boat to take maximum advantage of the Alfa Laval centrifuge and our tank setup. The six main fuel tanks are all integral to the aluminium hull and hold a total of about 14,500L/3825USG. The fuel in these tanks will be polished regularly via the Alfa Laval and then act as supply tanks we draw from to keep our 500L/132USG Day Tank filled up with clean fuel. These integral main tanks will be plumbed through a pair of manifolds and a high capacity fuel pump to be able to move fuel between any of these tanks. Other than in an emergency, these main tanks will not supply fuel directly to the main engine, as it is fed by the Day Tank. The bottom of this Day Tank is sloped down to a deep sump and the pickup out of this Day Tank will be on the high side of this slope to help ensure it only picks up clean fuel which will proceed through a Racor filter and then the fuel filter on the Gardner itself.

The return from the Alfa Laval will be plumbed to just short of the very bottom of each tank for the “stirring” reasons Papa outlined above and so too will the “draw” or supply lines to ensure that the Alfa Laval is picking up every bit of water and deposits that might have found their way into these tanks, so this is different than a more conventional filtering system. There will be a Racor filter between the In/Out manifolds and another between the Day Tank output and the main engine for added safety and each of these filters will be monitored by both N2K vacuum sensors to warn if either filter should be clogging and restricting fuel flow. I used a similar arrangement on the Gulf Cost Filter polishing system on my previous boat as I outlined previously and this served me very well so now with the significant added capacity of the Alfa Laval I think we will be even more assured of having clean clear diesel at all times and places we travel.

The Day Tank will have a sight glass for visual confirmation of its level and a sump with a water sensor alarm and a ball valve drain in the event anything does manage to make its way in. The levels of each of the integral tanks as well as the Day Tank will be monitored by both a digital pressure sensor (Maretron) and a manual Hart Tank Tender for backup. We have also designed a set of boxes built into the coaming just above deck level for Fuel and Fill and Vent lines. The Vent Boxes will be able to be sealed shut for any extended times we are at anchor or away from the boat to eliminate humid air getting into any partially full tanks. The Day Tank will have its own dedicated vent line with a shut off valve to keep the air inside it similarly protected.

I believe this will give us the best overall fuel system of any boat we have had or know of but would welcome any suggestions you or others here may have for further improvement and learning.
- Wayne

 

[Delfin]

Wayne, sounds like a great system. The only minor suggestion I would make is to designate a single tank to be the one you fill the day tank from. I keep that "staging" tank Uber polished, and polish the bulk tanks when the bulk tank is low, and filter/polish it when transferring to the staging tank. With the LV you'll have perfectly clean fuel, but with a Racor setup like mine I polish the bulk tanks at 30 microns and the staging tank at 10. The day tank gets continuously polished at 2 microns from the fuel return.

If I get a bad load of fuel, I can deal with it in the bulk tanks and between the staging and day tank know I have up to 350 gallons of fuel I can count on.

 

[greatpapabear]

Thanks for the kind wishes Papa Bear, we are having a blast for the past 3 years designing and now building our new boat and will do so even more once we launch which we hope to be by end of next year. The Alfa Laval was a great stroke of synchronicity and I couldn't be more delighted to be able to build such a fabulous fuel polishing system around it on the new boat and be able to have clean clear fuel at all times in all places.

Just a thought. If your tanks have baffles to reduce slapping, just ensure the outflow pipe(s) can reach behind all the baffles in case anything's lurking 'in the dark'.

Happy cruising.

 

[Codger2]

........ The levels of each of the integral tanks as well as the Day Tank will be monitored by both a digital pressure sensor (Maretron) and a manual Hart Tank Tender for backup.

I also have a Maretron Fuel system monitor but my tanks use a ultra sound generator in a tube that determines the level of the fuel. I'm interested in knowing just how the Maretron digital pressure system determines the fuel level. For back up I also have a Hart Tank tender as well as the glass tubes on each tank.

 

[Bigsfish]

I have a Maretron and it is never accurate compared to the sight tubes. I need to have a new system installed. It’s nice to look at a gauge and see the remaining fuel.

 

[sunchaser]

Who
Be careful closing the vent lines into the tanks lest the tank build up vacuum or pressure thus creating another set of problems. You may want to consider a vent on each tank that allows the tanks to breathe. Several easy ways to do it while minimizing exposure to the outside elements.

 

[Whodgins]

Wayne, sounds like a great system. The only minor suggestion I would make is to designate a single tank to be the one you fill the day tank from. I keep that "staging" tank Uber polished, and polish the bulk tanks when the bulk tank is low, and filter/polish it when transferring to the staging tank. With the LV you'll have perfectly clean fuel, but with a Racor setup like mine I polish the bulk tanks at 30 microns and the staging tank at 10. The day tank gets continuously polished at 2 microns from the fuel return.

If I get a bad load of fuel, I can deal with it in the bulk tanks and between the staging and day tank know I have up to 350 gallons of fuel I can count on.

Thanks Delfin, that makes lots of sense and was what we've had in mind. With so much fuel the change in displacement as we use it up will necessitate us having a system of using fuel most forward first and then moving back through the tanks going aft. So we had thought of designating the aft most pair of tanks as our primary or as you called it "staging" tanks which we keep "uber polished" by the Alfa Laval and only draw fuel from there to the Day Tank. As you noted the fuel in the Day Tank will be even more finely filtered with the constant cycling of the return fuel and we are running this return fuel through a cooler prior to going back into the Day Tank to keep the fuel going to the engine as cool as possible.

Thanks for your suggestions, much appreciated.

 

[Whodgins]

Just a thought. If your tanks have baffles to reduce slapping, just ensure the outflow pipe(s) can reach behind all the baffles in case anything's lurking 'in the dark'.

Happy cruising.

Thanks PapaBear Yes, all our integral tanks are well baffled and being built as part of the well rounded hull they all slope down to the big keel bar running the full length of the boat and through the centerline of each tank. So the pickup and return pipes will be positioned up against this keel plate and hence the deepest point in the tank and these two pipes are positioned as far apart as possible so we don't end up with the return simply feeding right back into the pickup.

 

[Whodgins]

I also have a Maretron Fuel system monitor but my tanks use a ultra sound generator in a tube that determines the level of the fuel. I'm interested in knowing just how the Maretron digital pressure system determines the fuel level. For back up I also have a Hart Tank tender as well as the glass tubes on each tank.

We will be using three Maretron FPM100 Fuel Pressure Monitor "black boxes" with pressure senders from 6 tanks to each one. The pressure sensing unit sits on the bottom of the tank and simply measures the pressure/weight of the column of fuel/water above it and sends this reading back to the FPM100 and onto the N2K bus. This is a more cost effective solution when you have lots of tanks as we can have 6 sensors per FPM100 whereas the Ultrasonic based TLM100 units are both the sensor that bolts to the top of the tank and the "black box" that decodes the signal and puts it on the N2K. The TLM has the advantage of nothing going into the tank but the pressure sensors are very robust, no moving parts and can be either allowed to sit on the bottom of the tank which is what we will do as each tank bottom is sloped toward the keel bar and so these pressure sensors will be nicely cradled in place. If you have larger flat bottomed tanks you install a "focus tube" bolted to the top of the tank and reaching down to the bottom with the pressure sensor sitting inside this tube. From those Captain's I've talked to that have these pressure sensor types they say they are quite accurate and consistent.

 

[greatpapabear]

Thanks PapaBear Yes, all our integral tanks are well baffled and being built as part of the well rounded hull they all slope down to the big keel bar running the full length of the boat and through the centerline of each tank. So the pickup and return pipes will be positioned up against this keel plate and hence the deepest point in the tank and these two pipes are positioned as far apart as possible so we don't end up with the return simply feeding right back into the pickup.

This sounds like the most exciting project i've come across in ages. When installing the 'blowpipe' as I call it, it you can create a swirl effect like a whirlpool from the bottom, that would be simply perfect.

 

[Whodgins]

Who
Be careful closing the vent lines into the tanks lest the tank build up vacuum or pressure thus creating another set of problems. You may want to consider a vent on each tank that allows the tanks to breathe. Several easy ways to do it while minimizing exposure to the outside elements.

Quite right sunchaser, Christine and I discuss this a lot and we do need to ensure that the vent lines can not be left closed off when we are drawing from them. This should be straight forward with the main tank vents going to the two dedicated vent boxes on each side of the PH coaming as we would only put these in when we are leaving the boat for extended amounts of time. We would therefore have the sealing off of these vent boxes part of our "leave the boat" checklist and have their removal on the "recommission the boat" when we return. The shut off valve for the Day Tank vent will be up above the Day Tank and the fuel manifolds so easy to get at and right there when you are filling or using the Day Tank and we will have a "red tag" that goes on this valve handle whenever we close it which would again be part of our leave/return to the boat lists.

Always room for human error of course but we are pretty good at adhering to our protocalls and habits with critical things like this and barring a serious "senior moment" we should be good.

 

[Whodgins]

This sounds like the most exciting project i've come across in ages. When installing the 'blowpipe' as I call it, it you can create a swirl effect like a whirlpool from the bottom, that would be simply perfect.

It has been a great adventure in the 3 years since we started designing this boat and all the more so now that we're in the building stage. Naval Yachts who we are building the boat with here in the Antalya Free Zone in Turkey have assembled a fabulous "Team Mobius" with us (name of the boat) and it is a joy coming to work here every day. I do my best to publish a weekly update of our progress on our Mobius.World blog so please join us there anytime you're interesting in seeing the photos, videos and explanations of where we are at each week.

As for the pickup and return pipes into the tanks, I think we have them designed and positioned along the lines you suggest but I will maybe shape their bottoms a bit more to help with the "swirl effect" you suggest. Thanks!

 

[greatpapabear]

It has been a great adventure in the 3 years since we started designing this boat and all the more so now that we're in the building stage. Naval Yachts who we are building the boat with here in the Antalya Free Zone in Turkey have assembled a fabulous "Team Mobius" with us (name of the boat) and it is a joy coming to work here every day. I do my best to publish a weekly update of our progress on our Mobius.World blog so please join us there anytime you're interesting in seeing the photos, videos and explanations of where we are at each week.

As for the pickup and return pipes into the tanks, I think we have them designed and positioned along the lines you suggest but I will maybe shape their bottoms a bit more to help with the "swirl effect" you suggest. Thanks!

Just subscribed. Quick question - I've looked for the overall spec but coun't find it. LOA etc. Have I looked in the wrong places?

 

[Delfin]

Quite right sunchaser, Christine and I discuss this a lot and we do need to ensure that the vent lines can not be left closed off when we are drawing from them. This should be straight forward with the main tank vents going to the two dedicated vent boxes on each side of the PH coaming as we would only put these in when we are leaving the boat for extended amounts of time. We would therefore have the sealing off of these vent boxes part of our "leave the boat" checklist and have their removal on the "recommission the boat" when we return. The shut off valve for the Day Tank vent will be up above the Day Tank and the fuel manifolds so easy to get at and right there when you are filling or using the Day Tank and we will have a "red tag" that goes on this valve handle whenever we close it which would again be part of our leave/return to the boat lists.

Always room for human error of course but we are pretty good at adhering to our protocalls and habits with critical things like this and barring a serious "senior moment" we should be good.

Just as an FYI, but when I designed Delfin's venting, I provided for a single 2" vent pipe that all tanks are connected to that goes up the dry stack raceway to above the pilot house where it terminates in an "upside down U" so rain water can't get into it. I do have shut off valves for each tank vent, but never close them. In 11 years of active use, I've never seen any water in any tank, ever, so I guess it works. My point is, I'm not sure closing tank vents needs to be something to remember to do and undo.