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-   -   Holding tank monitoring options? (https://www.cruisersforum.com/forums/f115/holding-tank-monitoring-options-181279.html)

SaltyMetals 11-03-2017 05:14

Re: Holding tank monitoring options?
 
Peg, i think you are the recognised guru when it comes to this subject ( I have read some of your stuff before elsewhere). I need a unit (plastic holding tank in a Jeanneau 43ds) and like the idea of the Gobius (Tankmätare för båt och fritidshus) which requires no holes in the tank with the sensors being attached on the outside. As posted by OttowW yesterday. You have not commented on this unit so far. Nobody else seems to have commented on this unit either.

do any of you guys out there have experience of the Gobius?

rwidman 11-03-2017 07:35

Re: Holding tank monitoring options?
 
Quote:

Originally Posted by canyonbat (Post 2343971)
We have the SCAD Solo external tank sensor. Nice when it works but very unreliable. Often shows full or 3/4 when tank is empty. I could say the same thing about the electronic sensors inside our RV holding tank (different brand I think). I never know when to trust them. Like a broken clock, they are probably right at some point in the cycle.

You might not have read my post (#8) above, but that's my problem and it's caused by sewage sticking to the inside wall of the tank. Even though the tank may be empty, there's enough poop on the wall that the sensor senses it and thinks the tank is full.

How do I know that's the problem? If I manually clean the inside of the tank wall, the system works and shows the correct level.

LeaseOnLife 11-03-2017 08:17

Re: Holding tank monitoring options?
 
Quote:

Originally Posted by zboss (Post 2343829)
2nd the tank tender. Its put in through the top but you can drill a small 1/2" hole through the top of your bunk to gain access to the top of the tank. Then, its only a 1/8" tapped hole in the top of the black water tank to screw in the sensor with a little bit of sealant. The tubing is only about 1/8" polypropylene so its easy to run.

Why bother with another electrical system when a perfectly good mechanical system works so well? No wires to run and nothing to corrode.

I have the tank tender for fuel and water tanks, it works great. But I am hesitant to recommend or use it for a waste tank. One first has to clear the capillary tube in the tank by pumping air in to it. Then the fluid creeps up the capillary tube, creates a little back pressure which in turn is shown on the pressure gauge. I cannot imagine this could work reliably with poo and bits of paper blocking the capillary tube.

Does someone have first hand experience with the tank tender for waste tanks? As said, I like the system for any other fluid.

Dirk

Pizzazz 11-03-2017 08:26

Re: Holding tank monitoring options?
 
One unorthodox solution in your case will be to install a T in your discharge tube then connect a vertical PVC tube (those semi-transparent ones used for sink drains) then connect it to the vent line. You will be able to read off the level directly off the PVC tube (you can even mark it with a scale). Depending on how creative you want to get with the hoses you can position the PVC tube where you could easily see it.

In my case (I have a very similar holding tank arrangement) I just drilled a hole through the V-berth.

peghall 11-03-2017 08:33

Re: Holding tank monitoring options?
 
I strongly suspect that cleaning the tank manually may also clean the senders at least enough to let them work again.

If the tank walls require cleaning very often, try flushing a cupful of strong detergent (engine degreasers are good for this) anywhere from daily to weekly depending on how long between pumpouts. It won't interfere with any tank product, and should reduce the fats buildup on the senders and the tank walls. It'll also reduce fat buildup in the toilet discharge hose, helping to slow the buildup of sea water minerals.

zboss 11-03-2017 08:44

Re: Holding tank monitoring options?
 
Quote:

Originally Posted by LeaseOnLife (Post 2344441)
I have the tank tender for fuel and water tanks, it works great. But I am hesitant to recommend or use it for a waste tank. One first has to clear the capillary tube in the tank by pumping air in to it. Then the fluid creeps up the capillary tube, creates a little back pressure which in turn is shown on the pressure gauge. I cannot imagine this could work reliably with poo and bits of paper blocking the capillary tube.

Does someone have first hand experience with the tank tender for waste tanks? As said, I like the system for any other fluid.

Dirk



We have been using ours flawlessly in the black water tank for over a year with zero problems. If you are really concerned you could simply unscrew the 1/4" top off the tank, pull the poly tube out and clean it... but never had an issue.

It's the most reliable thing on our boat.

peghall 11-03-2017 08:44

Re: Holding tank monitoring options?
 
I wouldn't tee any line that carries sewage into your tank vent line... repeated overflows into the vent line--which can happen when heeled--can result in a blockage in the vent line.

I like your suggestion to drill a hole in the v-berth to gain access to the top or end of the tank. I cut out the whole cover in two pieces and installed furring strips around the edges of each side for the covers to sit flush on the opening when I put it back.

LeaseOnLife 11-03-2017 08:53

Re: Holding tank monitoring options?
 
Quote:

Originally Posted by zboss (Post 2344463)
We have been using ours flawlessly in the black water tank for over a year with zero problems. If you are really concerned you could simply unscrew the 1/4" top off the tank, pull the poly tube out and clean it... but never had an issue.

It's the most reliable thing on our boat.

Interesting, Thank You

Dockhead 11-03-2017 09:44

Re: Holding tank monitoring options?
 
Another voice for the Tank Tender. This is going to be the easiest device for you to install, because it requires only one tiny hole anywhere in the top of the tank. You will only need a small hole in your v-berth to get enough access.

This is a brilliant device -- extremely simple and totally reliable, just about immune to any kind of clogging. Uses no electrical power. Unfortunately you pay a lot for this elegant simplicity -- it's expensive.

I use a Maretron ultrasonic sensor, which is pretty good and pretty resistant to clogging. It connects to the N2K network so no separate display is needed and wiring is simple. It's a decent solution, but requires a standard size inspection port in the top which might not work for you.

I would go with Tank Tender if I were you. I hate holding tanks and feel sympathy for your situation. One of the single best things about moving from cruising in U.S. waters to the European Atlantic coasts, is pumping straight out almost all the time and not futzing with holding tanks much.

ottow 11-03-2017 16:20

Re: Holding tank monitoring options?
 
Quote:

Originally Posted by SaltyMetals (Post 2344337)
Peg, i think you are the recognised guru when it comes to this subject ( I have read some of your stuff before elsewhere). I need a unit (plastic holding tank in a Jeanneau 43ds) and like the idea of the Gobius (Tankmätare för båt och fritidshus) which requires no holes in the tank with the sensors being attached on the outside. As posted by OttowW yesterday. You have not commented on this unit so far. Nobody else seems to have commented on this unit either.

do any of you guys out there have experience of the Gobius?


Have not tried them myself, but these are pretty common here in the Nordics and get excellent reviews by most ppl and magazines. Sure beats drilling into your tank...

OldGreyB 11-03-2017 23:55

Re: Holding tank monitoring options?
 
Kelkara,
Looking at your port side photo again, I have a suggestion if you go the pneumatic route.
Where the apparent vent line is exiting the tank at the top. Cut and install a hose T there. Then add a short length of hose, connect a barbed hose to male thread fitting. At the male thread end , use a female socket union and then connect the male packing gland that will hold the ¼” or 1/8” pneumatic hose. If the supplied sensor does not have a good weight on it, to ensure the sensor hose lays on the bottom of the tank, drill slightly oversized hole in a oblong fishing sinker, two pot epoxy the hose into that and drill the tube pressure outlet hole above that. Slide the whole sensor lot though short hose, then via the long part of the tee and tank inlet into the tank. Tighten the coupling and packing gland when sufficient sensor length has installed.
What ever you do, happy sensing.
:biggrin:

captstu 14-03-2017 16:41

Re: Holding tank monitoring options?
 
I've been dealing with Dennis Forrrielo for the past year. He sold me the replacement that works fine. I am shipping the old one back to be tested, and he wants to charge me a repair and replacement fee if it's broken.

peghall 14-03-2017 18:04

Re: Holding tank monitoring options?
 
Methinks there may be more to this story, 'cuz that doesn't sound like the Dennis I've known for more than 20 yrs.

Dockhead 15-03-2017 04:08

Re: Holding tank monitoring options?
 
Quote:

Originally Posted by LeaseOnLife (Post 2344441)
I have the tank tender for fuel and water tanks, it works great. But I am hesitant to recommend or use it for a waste tank. One first has to clear the capillary tube in the tank by pumping air in to it. Then the fluid creeps up the capillary tube, creates a little back pressure which in turn is shown on the pressure gauge. I cannot imagine this could work reliably with poo and bits of paper blocking the capillary tube.

Does someone have first hand experience with the tank tender for waste tanks? As said, I like the system for any other fluid.

Dirk

Tank Tender works great with black water tanks. NO FLUID needs to be inside the tube -- it doesn't work the way you describe. The pressure is sensed in the AIR when the pump is activated, not fluid. It automatically cleans itself.

The only other type of sensor which really works reliably, in my experience, is ultrasonic INSIDE the tank, with a baffle to keep solids away from it.

The mechanical float type also works more or less OK provided it has be proper baffled tube, but subject to clogging sometimes and also subject to mechanical failure like all mechanical sensors.

Kelkara 15-03-2017 11:16

Re: Holding tank monitoring options?
 
Thanks for the good ideas everyone. My current thinking is ...

SCAD system - very difficult to install in the restricted space, and will only monitor the top few inches of the tank, so not much better than a "3/4 full" warning.

Gobius - easier to install, but only gives a "3/4 full" warning.

Tank Tender - simple and reliable, but still requires a small fitting in the V-berth, but that can probably be protected ... also very expensive. Home-made alternative? am I that brave when it comes to playing with sewage?

Mechanical sender - if I ever need to access the inside of the tank it will require cutting an inspection hatch into the V-berth, and so installing a sender at the same time would make sense ... but the tank ain't broke yet.

I've got some thinking to do ... but thanks again for the ideas.


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