Poop tank project

[Delta Riverat]

Yeah, that's the plan. And if it does I can now flush it with a hose

Soldered it.

Now last, but not least, the bubbler -

 

[Delta Riverat]

Installed;

Just have to apply a little sealant to the gap between the vent pipe and my mate.

 

[HeadedToTexas]

Classy fitting. Mine is much more “production,” though similar in design and function.

 

[Delta Riverat]

Poop tank project completed, air pump installed;

The air pump hoses go to a couple of 1/8" brass tubes I soldered into the end of that 1/2" brass cap. And then it's all 3/8" plastic tubing and push on fittings all the way to the tank pipe which is also 3/8" plastic that I steamed a bend in so the last foot and a half would lie flat on the bottom of the tank. The last foot and a half has a couple dozen 1/16" holes drilled in it.

I got the pump started up and yeah, it's real quiet. Let it run for a half hour and stuck my nose close to the vent. I could smell "tank fumes", but they were nothing like the foul stench of past. And I got a whiff of those the last time the marina pumped the tank not more than a month ago. At 5 liters a minute the pump should have delivered 150 liters or about 40 gallons of air to my 35 gallon tank which is not empty.

So happy and smiling, I proceeded to the head and flushed some "noflex digester" down to the tank with a gallon of water. Summertime will tell the tale but for now I'm happy -

 

[Comodave]

You will enjoy the bubbler system.

 

[Bacchus]

Nice work Roger... I can guarantee that your time spent to add the bubbler will be time well spent!

 

[Pprior]

Maybe I missed it, is the bubbler system just basically like an aquarium bubbler that's pumping air into the tank to keep it moving around? Never heard of this before.

 

[Delta Riverat]

Yeah, exactly. I think Dometic makes a high dollar version just for the purpose. It's not so much about the movement (hehe, good pun eh) it about the fresh air which enables an aerobic tank which always smells better than an anerobic tank.

 

[Comodave]

Groco makes a bubbler system. The goal is to pump oxygen up through the poop so you will have aerobic bacteria growing not anerobic bacteria since the anerobic bacteria really stinks.

 

[Bacchus]

Maybe I missed it, is the bubbler system just basically like an aquarium bubbler that's pumping air into the tank to keep it moving around? Never heard of this before.

Peggie and her book motivated me to try the DIY approach that essentially does what the Groce Sweet Tank does for a LOT LESS $$$.
I think the Groce system was $350+ when I looked. the DIY version will be under $50 all-in with pump, fittings, etc. Runs on less than one amp 12V... actually less than o.5 A if I remember correctly. My pump ( like the pic) has been in operation for about 10 seasons.
My Baccus website - linked in signature - Projects section has a detail on tank aeration.

 

[Delta Riverat]

If you have the dreaded "it stinks bad every time I flush the toilet" then you need this. On my boat it was really bad as the tank vent is right under the saloon window. And when it's summer time that window as others is open. So when anyone goes (even if it's just pee) that 2-3 quarts of flush hits the tank and displaces an equal amount of "tank gas" out the vent.

Yeah it was really bad...

 

[Comodave]

I have been putting bubbler systems in our boats for about 25 years and find that they work very well.

 

[HeadMistress]

A bait box pump is more durable than a fish tank bubbler. "Perforate" (poke holes in the top of) some 1" sanitation hose to run across the tank near the bottom.

--Peggie

 

[HeadMistress]

There's a bit more you need to do in addition to the bubbler (aerator): Replace the "vent" thru-hull and any clamshell over it with an open bulkhead (aka "mushroom" fitting that will let the tank breathe... straighten out the vent line and GET RID of any brass or copper fittings. With the possible exception of a ship's bell, brass has NO place anywhere on a boat...copper won't survive long in a sanitation system.

And btw, in case you didn't know, an aerator MUST run 24/7/365 whether you're on the boat or not, 'cuz without oxygen the tank will quickly turn anaerobic (STINKY!) and can take several hours to recover after it's turned on again, during which time the aerator will be pushing gradually diminishing stinky air out the vent. It should only be turned off when tank is empty for winter or other extended layup.

-Peggie

 

[Capt Helges]

Is in full swing. Already installed the new level sensor so I now know how full the tank is. I also know that I have a vent problem. I know it works because it stinks when I flush, the vent outlet is right under a saloon window so when the windows are open in the summertime...everyone knows when you goes.

Have the DIY bubbler parts too and the circuit run for it installed when I did the sensor install. But wanted the sensor in before the bubbler as the air line into the tank is right in front of the sensor rod. But I also need a better vent.

Today I investigated the vents. They are clamshell type but only the covers on the outside of the hull. The venting to the outside is half inch copper pipe. So, next visit will be removing the 3 screw SS "clam covers" to see what is on the other side. In addition I have to pick the right one (the stinky one) as I have five of them lined up next to each other. So, I'm thinking 2 diesel, 2 water and 1 stink hole. Shouldn't be hard to identify and will be fun taking the screws out to see what I'm dealing with. When I have the right hole I'm sure I can replace the cover with a "mushroom" of some type.

The vent fitting out of the tank is a 3/4" MPT to half inch barb. This is the problem I'm sure. The inside of a half inch barb fitting must be what 3/8" No wonder I've been having pump out problems. The tank when full will have waste in this fitting which I've already verified. This will be replaced with a 3/4" MPT to 3/4" barb with 3/4" hose and connected properly to the existing outside vent hose.. Another thing I saw today was the half inch hose out the vent going straight into the hose leading to the hull vent. No adapter, just a hose stuck into another hose.

These old boats...

Mine has a filter on the vent line to eliminate odors.

 

[SteveK]

Mine has a filter on the vent line to eliminate odors.

don't ever let it get wet

 

[Bacchus]

Mine has a filter on the vent line to eliminate odors.

To be clear... filters do not "eliminate odors" they actually ensure odors. If working properly they can contain the odors inside the tank. If you believe filters are THE ANSWER do some searching here on TF to see the number of boats than have problems with their filters. Granted, many of the issues are due to poor installation, maintenance, etc,

Aeration on the other hand can actually eliminate odors with very little maintenance or replacement costs. .. why bother installing potential problems when there is a better fix?

 

[Delta Riverat]

Went to the boat today and sealed the gap to my vent adapter. The sound of bubbling can be heard at the vent. Absent from this location was any odor at all. Yeah Baby! Been running constant 4 days now and the pump just gets a little warmer than ambient, not many watts used at 400 mA.

This works so good I ordered up a spare so I can replace if needed. Next time I wash the boat I'll flush the vent line with the garden hose to "purify" that as well -

 

[Comodave]

Mine has a filter on the vent line to eliminate odors.

That isn’t a good thing. Get rid of the filter and introduce more oxygen into the tank.

 

[Comodave]

Went to the boat today and sealed the gap to my vent adapter. The sound of bubbling can be heard at the vent. Absent from this location was any odor at all. Yeah Baby! Been running constant 4 days now and the pump just gets a little warmer than ambient, not many watts used at 400 mA.

This works so good I ordered up a spare so I can replace if needed. Next time I wash the boat I'll flush the vent line with the garden hose to "purify" that as well -

The first bubbler I put in was into an 80 gallon holding tank that was extremely bad on smell when we flushed the head. It could knock you off the dock. I installed the bubbler and turned it on. Peggy had said it would take 2 hours to purge the smell. At 2 hours and 5 minutes the smell was gone. We had tried everything to get rid of the smell and all it took was some air. Amazing.

 

[Delta Riverat]

Count me in on "it works" list. One of the best boat mods I've done and so cheap and easy too.

I googled poop and found it like 98% anerobic vs 2% aerobic bacteria. But just give the good guys some air and they will prevail.

 

[HeadMistress]

Re aerators/"bubblers:" One of you posted within the last couple of days that you ran the "perforated" hose inside the tank ON the bottom of the tank...I can't find the post to reply that it was a BAD idea because even the slightest amount of sludge on the bottom the tank will clog the holes in the hose, even if they're on the top of it. Flushing the toilet can stir up the tank...so can bouncing around in other boats' wake or messy seas. It should be run 3-4" above the bottom to keep it far enough off it to keep the holes open.

Fwiw, this was a problem for Groco the first year their aerator was on the market...they had to redesign their hoses and move 'em off the bottom to fix it.

--Peggie

 

[Delta Riverat]

If that happens I'll just hook the tubing up to a higher pressure pump and blow it out. I'll add that it's far from flat also. This tubing comes in a roll and has a set curve in it. I just used the steam so I could bend a 90 in the last 18 inches. You can picture it as the "roll curve" heading down from that top 1.5" adapter to the tank bottom and then bending along the bottom in another "roll curve"

It's "sorta" on the bottom. Far from flat and far from straight. Not going to worry about it.

 

[SteveK]

Peggie, I was wondering about the ideal placement, you suggest 3-4".
Always wondered what keeps a pipe full of air near the bottom and whether it needs to be down there. I mean non bubbler systems that have passive air with an unrestricted thru hull seem to do well too.

 

[Delta Riverat]

The Groco guys have their outlet right on the bottom, I was following their lead.

 

[HeadedToTexas]

My new vent line will get a testing over the next few months. If it is short of ideal, I will be next in line for the bubbler upgrade. The pump draws just 400 mA? So that's 0.4 amps at 12 VDC, right? Or 4.8 watts? And if it runs 24 hours a day, that's 4.8 x 24 = 115.2 watt hours per day, yes? Not bad.

 

[HeadMistress]

The Groco guys have their outlet right on the bottom, I was following their lead.

Theirs uses a custom designed hose. I posted earlier that they had problems with the first hose they used becoming clogged by sludge, sending them back to the drawing board for a solution.

--Peggie

 

[Bacchus]

My new vent line will get a testing over the next few months. If it is short of ideal, I will be next in line for the bubbler upgrade. The pump draws just 400 mA? So that's 0.4 amps at 12 VDC, right? Or 4.8 watts? And if it runs 24 hours a day, that's 4.8 x 24 = 115.2 watt hours per day, yes? Not bad.

Exactly! I believe it b work work fine using a 25% to 50% duty cycle but I could never find an adjustable timer to do some experimenting with. At the low A draw full time operation is not a problem.

 

[HeadMistress]

Always wondered what keeps a pipe full of air near the bottom and whether it needs to be down there. I mean non bubbler systems that have passive air with an unrestricted thru hull seem to do well too.

Successful passive ventilation above the surface of the contents depends several things--length of the vent line, how straight it is, how much it rises (45 degrees is the max that can allow any air exchange with the gasses in the tank because ambient air doesn't fall and the gasses in the tank don't rise), and the depth of the tank. Tank contents below about 20" turn anaerobic by necessity. Vent thru-hull location can matter too....tanks that vent out the transom get -0- air exchange...clam shells allow very little. "Vent" thru-hulls--designed to keep sea water out of fuel and water tanks--allow some...that depends on its location on the hull...is it where any air can be forced into the tank by motion of the boat? And while replacing it with an open bulkhead fitting will help a lot, it doesn't do nearly as much as aeration 'cuz oxygen is essential to odor prevention.... Bio-physics 101: when organic material breaks down AEROBICALLY, it converts to CO2, which is odorless. You can't get too much oxygen in a tank.

--Peggie

 

[HeadedToTexas]

My new vent line is a few feet longer than your limit, Peggie, but it meets most of your parameters. Constant rise, tank depth is way less than 20" and the through hull is amidships on the port side. Fingers are crossed.