Tank level monitoring opinions
 

Hey all,

Wondering what you all have done about problematic tank monitoring systems? My boat has the problematic Dometic/Sealand probes, the long modules that dip in and read empty, low, mid and full. I've replaced the module once a few years ago, but it's not reliable again. I'm ready to try something else, just putting the same crappy sensor back in seems silly.

It seems like the thing to do is either the stick on modules on the outside of the tank (Gobius tank monitor type of thing) for around $250, or a higher end ultrasonic thing (Raritan TLM 100 and display) for A LOT more.

What would you do?

Having 2 little kids that like to flush a lot, tank levels are important to us. We don't spend extended times away from the dock, maybe 2-3 days max, and pump outs are free for us at our marina.

I do have interest in the NEMA 2000 type of system, I'm interested in hooking up my Mercury Smartcraft engine data to a smart device (laptop, MFD or other thing) but it's not a must, but to be able to see stuff on a NEMA 2000 network would be cool.

Trying to balance basic needs of tank level monitoring on the cheap, to spending $1000 to monitor a tank with future expansion options.

Are there other brands or systems you'd recommend?

Thanks tons!

(PS, boat is a 2006 Monterey 302 cruiser, twin 5.0 MPI's.....someday to be traded for something more trawler-like!)

We have the dometic sensor you mentioned. What we did was buy another sensor. We have easy access to the top of the tank where the sensor is. I made quick disconnects for the electrical connnections. We simply unscrew and swap sensors at every 2nd or 3rd pumpout. It takes an extra 5 minutes. The removed one is cleaned and stored in a PVC canister I made. They rarely "go bad" in my opinion - they just need regular cleaning.

Project is written up here: https://docs.wixstatic.com/ugd/d19c2...11590fc957.pdf

Ray
--
m/V SCOUT, N37
https://n37scout.wixsite.com/travels
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I believe after having boats with all the other brands of monitors that the "stick on the outside of the tank" is the absolute best!

I replaced the pneumatic system that my boat had with the SCAD system, and we've been very happy with it. I used the in-tank sensors which I'll (over-?) simplify as being the same as the external stuck-on sensors but enclosed in a PVC pipe. I've done the holding tank and our 4 water tanks and plan to do our fuel tanks but haven't gotten that done yet.

Knowing tank levels accurately is one less thing to worry about and worth the expense. Now to get those danged fuel tanks done so that we know how much fuel we have!

I replaced the same probe system you have with the Scad system and it has been flawless for going on 5 years now.

Ken

I am currently using the Gobius system. It works as advertised.

I use the Gobius system on my waste tank, and the Maretron TLM sensors on my fuel and water tanks.

I've used the Maretron ones for a number of years, and they are perfect for water, diesel, etc. but I prefer not cutting holes or having any possibility of issues with waste tanks. The stick-on versions like the Gobius are good enough and don't require any holes.

Another happy SCAD system user here. I removed the in-tank sensors and replaced them with a screw in cap. (we have two separate head systems)

We have the WEMA system, but otherwise similar set-up. OTOH, we've only had to change sensors every 2-3 years or so...

-Chris

I have a Maretron in-tank pressure sensor that's going to get installed in the coming weeks. I'll report back how the install goes.

Anyone tried the Moeller Marine Electrical Reed Switch Fuel Sending Unit, the user reviews are quite good. I am about to install two new 80 gallon tanks for gas and I know from my RV background, sensor readings can crap out on you easily.


https://www.amazon.com/Moeller-03576...ustomerReviews

The Maretron ultrasonic sensors don't work well on black and gray water, so don't waste your money. I expect other ultrasonic devices will have similar issues.


On the other hand, their submersible pressure transducer works very well in both gray and black water. These are what Wkearney99 is installing.



I've never tried the stick-on-the-outside devices because outside of my tanks were not accessible.


The sealand/dometic device is very crude (we have one in addition to the Maretron devices), but all they ever needed was cleaning to get them working again.

Correct. What it'll take is time for me to drill one hole in the poly tank and install the gateway. Should be a pretty straightforward job. The N2K wiring being the most complicated part of it.

I've had just about every other kind of tank monitor (floats, tubes, external foil) and I was not happy with any of them, for various reasons.

Removing them and cleaning is a simple fix.

I went with one of the exterior mounted Profile tank systems. It has only been installed a relatively short time. I think it works well IF your tank has a side that accessible and free of metal fittings. Mine was accessible but there were some metal fittings that were not in an ideal location (output fitting primarily). Even so, it seems to work well. You just have to calibrate properly.

Same here. Made quick disconndcts, I can unscrew sensor head, clean sensors & replace in less than an hour. Usually digested animation fats are the culprit for sensors sticking according to Peggy Hall (these clean up quickly in soapy water). A few of us have had hard struvite crystals form on the sensors. These require an acid soak such as CLR overnight, then a quick scrub & you're good for several seasons. $10 solution.

For what it’s worth, flushing with some fresh water as part of every, or every other pump out goes a long way to keeping any sensors clean for longer

For fuel, we are blessed with calibrated sight tubes. Accurate to 0-2% at any tank level. Calibration for a non cubic tank is an issue to be solved for deciding on any measuring technique. If you're using a stick on unit, be sure they can be calibrated for varying volumes as tank empties.

For black water, as does TT, we flush with fresh several times during the season and "layup" with fresh water. When the Sealand probes gum up I lossen the tank top fitting and jiggle the probe. No problems for 14 years now doing this.

Thanks all for the replies! Great information as always.

I tried the cleaning method on the last sensor, it would last a few weeks and then stop working again. Thought it was just old. New sensor up has the same problems. Getting to the tank means taking a bunch of stuff out of the boat, and digging into a wall. Not an easy task.

I think I’ll try one of the stick on models as the tank is easily accessible for installation of those.

Thanks again to all for the comments!

Years ago, I installed a couple of these monitors that are the same as SCAD without the badging for a few bucks less. One for the fresh water and one for the holding tank. Great product and installation support by Dennis Ferreillo.

If one broke today, I'd be shopping for the same model tomorrow.

https://www.ferriellosales.com/monitoring-systems.html

I bought mine from him as well. He and his wife seem to be a delightful couple, at least over the phone. My impression (and as usual I could could be wrong) is that he licensed or sold the patent to SCAD for the tank monitors but also was able to continue to sell them himself. It was less expensive to buy through him directly.