Holding tank monitor recommendations?

Noah · January 04, 2016, 05:27:45 PM

Had another great New Years week, sailing in sunny CA. No intent to rub it in for our friends in the cold climes... However, a great weekend almost turned into a disaster. Had lots of guests aboard and with that comes plenty of head usage. all went well, out of sight out of mind. However, when I was tidying up after the fray, much to my confusion, I found that the portside settee cushion and its wood foundation board, wouldn't sit down flat on the settee. What??? After some head scratching. (maybe pun intended) I discovered the seat board was rocking on top of the holding tank vent fitting on the top on of the tank. Apparently the holding tank was SO FULL IT DEFORMED upward so that it was sticking up above the fiberglass! For some miracle it didn't burst! Upon further discovery, I found a trickle of "water" in the shower pan channel that was coming from the Jabsco head valve assembly when I pumped. I guess there was the point where the pressure decided to relieve itself, after the tank couldn't hold another drop?! Just a trickle, no spill anywhere, and no smell. Not at the vent stanchion, not at the tank plumbing, not at the tank deck cap. Whew! I was afraid of opening the deck cap at the dock and getting a fountain, and waited worriedly until the next day (dreaming of geysers) then did little solo cruise three miles out to sea and used the macerator. Disaster averted!

So now to my question. In addition to my keeping a closer eye on what's happening on my boat, I am looking to install a tank gauge. Anyone have any recommendations?

britinusa · January 04, 2016, 06:26:53 PM

Our boat, our rules:

If you didn't eat or drink it - don't put it in the toilet bowl
Don't add water to the flush unless it's a #2

But just like you, we head off shore if you get my drift.

Paul

Stu Jackson · January 04, 2016, 07:22:42 PM

http://c34.org/bbs/index.php/topic,2698.msg14071.html#msg14071

Mick Laver · January 04, 2016, 07:53:29 PM

I can also recommend the Solo tank monitor (w/ full alarm) from FERRIELLO. The installation and calibration are fairly straightforward, it works, and it's relatively inexpensive. (http://www.ferriellosales.com/Monitoring_Systems.html). It looks like another vendor has re-branded the same system as their own and selling them for 15 bucks ($155 vs. $140) more. A slicker website (http://www.scadtech.com/tank_monitors) to be sure, but the same system.

You're welcome to take a look at mine if you'd like.

KWKloeber · January 04, 2016, 11:35:47 PM

Noah

Did you check the vent to ensure there's no dip to trap muck or a kink? That's notorious on the 30s.

You can make an inexpensive alarm using a cheapo lay on the floor high water alarm - they are available in 12v and you extend the sensors with light cable to your sensor. It ends up being only a 1-point alarm, but I find that sufficient set at 3/4 level.

Also unknown whether it would fit on the 34 layout, but I insralled a wet trap right after the tank outlet to ensure I can vac out to the last drop (without one you can vac down to only the top of the outlet fitting, then you lose suction).

Kk

Kk

Ted Pounds · January 05, 2016, 08:32:23 AM

I agree - check the vent. The only pressure should be from the weight of the contents. And your head valve should never be the pressure relief point. Instead you should have had leakage out the vent.

Ben H. · January 05, 2016, 08:34:35 AM

Quote from: KWKloeber on January 04, 2016, 11:35:47 PM
Also unknown whether it would fit on the 34 layout, but I insralled a wet trap right after the tank outlet to ensure I can vac out to the last drop (without one you can vac down to only the top of the outlet fitting, then you lose suction).

Ken, What is a wet trap? Do you have a picture you could share of this?

Noah · January 05, 2016, 09:35:25 AM

I have the standard stanchion vent. After I discharged at sea, I went to pump-out station and filled and pumped the tank multiple times with fresh water. The vent stanchion hole ran a clear stream of "overflow" water when tank was full...as usual ??? A mystery to me as to why "pressure relief point" was at the head pump handle during last weekend's "event". The vent hose is a pretty straight foward run...without bends/traps/kinks. Just happy the tank or hoses didn't rupture!

Roland Gendreau · January 05, 2016, 09:59:30 AM

I installed a holding tank monitor that lights up when the tank is nearly full. It was simple to install and has worked fine for years.

It is similar to this one:

http://www.marinediscounters.com/sealand-tankwatch-1-holding-tank-monitor/?gclid=CjwKEAiA8K20BRDetNv3p6DNhXwSJADSwa3t3ALfG8_4YUTX2isxGwxG4z9BQFEtQLCCJFqK1a1xjRoCWhHw_wcB

Ed Shankle · January 05, 2016, 11:09:49 AM

What I have found is that the vent hose coming off the top of the tank has a slight downward angle due the height difference between the tank fitting for the hose and the bottom edge of settee seat. The result is if you overfill, the tank contents will create a trap in the hose. then as gas gets created in the tank, it distorts the tank top. It doesn't need much, since the tank top fitting is just about touching the wood settee cover. That pressure isn't enough to push the trapped efluent all the way up and out the vent exit.
After that happens and after you pump out, try dinghy foot pumping some air through the vent opening after opening the decktop pumpout cover, to clear the hose of trapped efluent. Or, try manipulating the first few feet of the hose at the tank end to create enough downward angle for it to drain the hose contents back into the tank.
A tank monitor is on my agenda too!

Noah · January 05, 2016, 11:27:41 AM

That is probably what happened to me. My later filling and pumping multiple times with high pressure water from hose must have cleared any blockage. I just ordered a Profile multi-tank monitoring system. Decided to include two water tank sensors as well. Here's to ANOTHER non-budgeted, $450, wire-fishing, project...

KWKloeber · January 05, 2016, 02:15:27 PM

Quote from: Roland Gendreau on January 05, 2016, 09:59:30 AM
I installed a holding tank monitor that lights up when the tank is nearly full. It was simple to install and has worked fine for years.

It is similar to this one:

http://www.marinediscounters.com/sealand-tankwatch-1-holding-tank-monitor/?gclid=CjwKEAiA8K20BRDetNv3p6DNhXwSJADSwa3t3ALfG8_4YUTX2isxGwxG4z9BQFEtQLCCJFqK1a1xjRoCWhHw_wcB

Installed that same one, and after a yr the indicator light crapped out. So I had a little black project box from Radio Shack and mounted an LED in it and ran it into the head, mounted where it's sure to be seen.

kk

KWKloeber · January 05, 2016, 02:43:08 PM

Quote from: Ben H. on January 05, 2016, 08:34:35 AM
Quote from: KWKloeber on January 04, 2016, 11:35:47 PM
Also unknown whether it would fit on the 34 layout, but I insralled a wet trap right after the tank outlet to ensure I can vac out to the last drop (without one you can vac down to only the top of the outlet fitting, then you lose suction).

Ken, What is a wet trap? Do you have a picture you could share of this?

Ben, same principle as you have under your kitchen sink -- fills with water. As the pump out draws the yuck down to the top of the outlet air enters the hose and breaks the vacuum. With the trap lower than the outlet, it's the lowest point the vacuum draws on and "everything" in the tank will drain to the lowest point so when the suction breaksm you have the tank empty, or as close to it as one can get.

It's just 1-1/2" pvc drain fittings laid on top of the hull toward the engine stringer until it is lower than the tank outlet.

The pic isn't that great (it was of the M25, not the wet trap.) Remember I have a 30, so the layout is different and I could get a nice drop toward a low point and then back up to the hose.

From the tank outlet under the port settee - 90 ell / (2) 45 ells to snake into the position I needed / to a tee / out the side of the tee / 90 ell back toward the tank / 90 ell to the suction hose. The thru side of the tee faces "down" and I have a plug in case I ever need to drain it all. The tee and short pipe to the next 90 ell is the lowest point and forms the trap -- it's maybe 6?? inches lower than the tank outlet.

kk

Wayne · January 05, 2016, 03:25:19 PM

I installed one of the types that screws onto the inspection port on the top of my tank and has little floats that hang down into the tank. I find that the floats occasionally get gunked up with stuff (easily cleaned) but still I recommend away from this type of sensor. I later installed one of the 'stick on the outside' types for my water tanks, and have been 100% satisfied with this setup. Tank monitors have been a great upgrade; I'm sure you will be very happy when you get it done!

Noah · January 05, 2016, 03:42:24 PM

Stick-on external sensors is the way I am going, for all three of my tanks. However, after some quick reading/study on C34.org today, seems while applying them to the holding tank is doable, it will be a bit of a challenge and may involve wood cutting, reglassing, etc. I never pick the easy projects...