Holding tank monitoring options?

[Kelkara]

My holding tank is almost inaccessible, it is built into the fiberglass of the V-berth, with the top of the tank being the fiberglass bed of the V-berth.

I managed to get a picture of it by stuffing a camera down into the bilge through the anchor locker. The fittings are accessible through some holes cut in a bulkhead in the portside V-berth locker ... but otherwise I have no access to this tank at all - I think it's about 20 gallons size.

At the moment I have no real way of telling how much liquid is in it. I pushed an endoscope down the pump-out hose and it encountered a surprisingly clear liquid eventually, so the tank currently isn't totally empty.

Given the inaccessibility of this tank, does anyone have any ideas for how I can properly monitor the tank fill without putting a fitting right in the middle of the V-berth? ... or is simply counting flushing pumps the best way?

[peghall]

If you have access to the end of it--and from your photos it looks like you do--you can use a tank level monitor that has a sender which goes on the outside of the tank wall.

This one was top rated by Practical Sailor: Scad Tank Monitors However, it's just a private label label of the Profile System Profile Tank Monitors made by Ferriello Sales, which you can buy direct from them for a lower price. Check out the Solo model. If you have questions, Dennis Ferriello will be glad to answer 'em and give you all the help you need to install one. I've known him for 20+ years...he's one of the good guys.

"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/

[Kelkara]

Thanks Peggy - that's a really good suggestion I'll look into it further.

Unfortunately "access" to the end of the tank is one arm elbow deep through a hole at the bottom of the anchor locker ... so if the sensors can be installed one-handed and blind there may be hope.

However that wall of the tank at the bow end is only the top 5" of the tank which is about 15" deep at the aft end - but it would at least allow monitoring when the tank is approaching full.

The other possible issue is that the installation instructions say to install away from large metal objects ... this will necessarily be within about 1ft of the anchor chain ... I will contact Dennis and see what he thinks.

thanks.

[OldGreyB]

Another product that I have seen people in this forum recommend is “Tank Tender” Hart Systems - Home . Ofcourse none boating specific priced devices are available in the industrial market such as Afriso Unitel Pneumatic Tank Gauge .
Both these installation details shows the capillary tube into the top of the tank ( which you do not want) However you could install it via a tee the pump outlet line of the waste tank (if from bottom) but would have to valve off upstream on the outlet line when you want to obtain the level of the tank, so the pneumatic pressure signal goes to the tank (level) not venting overboard . If you are DYI guy then you can build yourself something similar with a squeeze bulb pump, 1/4 “ check valve, 2” pressure gauge from a trade shop and some nylon tubing. All work on the principal that the pressure created by the pump is equal to the liquid head pressure in the tank. Due to your tank configuration, to calibrate any of the above you would need to fill the tank to get the 100% reading , empty for the 0%m then mark your gauge accordingly 25%, 50 % ,75% based on the number of flushes required from 0 to 100%.

[mottseng]

On Peggy's advise I purchased the SCAD single tank monitor and it works perfectly. For me it eliminated the worry and not knowing how full I was.

Regards

[captstu]

I purchased a SCAD about a year ago. Installed it as directed and it worked PERFECTLY for one complete cycle - I set the high and low levels and pumpped out at about 3/4th full.

Then the readout panel went blank.

I contacted the manufacturer - shipped it back - then the problems started. They said the returned unit worked perfectly and complained about having to spend $6 or so to send it back. I offered them the $6, but they declined.

The returned unit still didn't work in my boat.

I checked for 12 volts at the feed, it read 13.2 v (on charge) at the two leads, 9 volts at the switch, and zero at the output of the switch - duh, the switch was bad.

More phone calls, more nonsense until I finally bought another readout since I had cut a hole in the boat to mount the unit and competing brands were a different size.

As you would expect, the second one read perfectly.

So, if you want a nice head monitor backed by an "attitude" - this is the device.

If you want a busted one, drop me a not and I'll ship it to you.

The mess cost me an extra hundred bucks - maybe I should just dump overboard?

[zboss]

Originally Posted by OldGreyB

Another product that I have seen people in this forum recommend is “Tank Tender” Hart Systems - Home . Ofcourse none boating specific priced devices are available in the industrial market such as Afriso Unitel Pneumatic Tank Gauge .
Both these installation details shows the capillary tube into the top of the tank ( which you do not want) However you could install it via a tee the pump outlet line of the waste tank (if from bottom) but would have to valve off upstream on the outlet line when you want to obtain the level of the tank, so the pneumatic pressure signal goes to the tank (level) not venting overboard . If you are DYI guy then you can build yourself something similar with a squeeze bulb pump, 1/4 “ check valve, 2” pressure gauge from a trade shop and some nylon tubing. All work on the principal that the pressure created by the pump is equal to the liquid head pressure in the tank. Due to your tank configuration, to calibrate any of the above you would need to fill the tank to get the 100% reading , empty for the 0%m then mark your gauge accordingly 25%, 50 % ,75% based on the number of flushes required from 0 to 100%.

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.

[rwidman]

I'll tell you my story even though it might not be much of a help. I purchased and installed one of the systems that relies on three sensors stuck to the outside of the tank. I don't remember the name, that's why my story might not help but if I were at the boat, I would have the name.


It's a dual system, meant to read the level in two tanks. The side for the potable water works fine although just having full, half full and empty isn't quite as useful as I would like.


The holding tank monitoring only works if I manually clean the tank walls on the inside of the tank. Once the tank is filled, sewage clings to the inside walls of the tank and the monitor reads full all the time.


No doubt there are systems out there that actually work, but at this point, it's easier to lift up the floor panel and look at the tank than buying and installing a different system.

[peghall]

I contacted the manufacturer - shipped it back - then the problems started.

If you contacted SCAD, they aren't the mfr...they just sell a private label branded version of the Profile tank monitors. You'd have gotten the help you needed had you known that and SCAD should have given you their contact info. If you still want to salvage it you'll find a link to the Profile site in my previous reply (post #2).

Peggie
"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/

[Dave22q]

Originally Posted by peghall

If you have access to the end of it--and from your photos it looks like you do--you can use a tank level monitor that has a sender which goes on the outside of the tank wall.

This one was top rated by Practical Sailor: Scad Tank Monitors However, it's just a private label label of the Profile System Profile Tank Monitors made by Ferriello Sales, which you can buy direct from them for a lower price. Check out the Solo model. If you have questions, Dennis Ferriello will be glad to answer 'em and give you all the help you need to install one. I've known him for 20+ years...he's one of the good guys.

"If you can't explain it to a six year old, you don't completely understand it yourself." --Albert Einstein
http://www.amazon.com/New-Get-Rid-Bo...dp/1892399784/

Dennis will do whatever it takes to keep you happy. Go to his site.

[Kelkara]

Originally Posted by zboss

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.

The nothing to corrode is an important issue, although I don't think it will get "wet" very often, but since the anchor locker drains into the bilge here it is a very humid environment.

The pneumatic sensors sound attractive, the problem is that, as far as I can tell, the top of the bunk IS the top of the tank, so that fitting will be sticking up into the cushions ... and if it ever even drips, bedding and sewage are not a good combo!!! Installing something down the pump-out hose is an intriguing idea though.

[canyonbat]

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.

[ottow]

Originally Posted by Kelkara

The nothing to corrode is an important issue, although I don't think it will get "wet" very often, but since the anchor locker drains into the bilge here it is a very humid environment.

The pneumatic sensors sound attractive, the problem is that, as far as I can tell, the top of the bunk IS the top of the tank, so that fitting will be sticking up into the cushions ... and if it ever even drips, bedding and sewage are not a good combo!!! Installing something down the pump-out hose is an intriguing idea though.

Not sure if these can be sourced where you are at, but it offers a solution that does not require any drilling of holes and could possibly be mounted one-handed since the sensor(s) simply glue on to the side of a tank:
Tankmätare för båt och fritidshus

[peghall]

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.

Try recalibrating it.

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.

They aren't really electronic, they're float switches that turn on a light when the level in the tank gets high enough to push each one up enough make contact with its "brother." The problem with ALL internal senders is that they become coated with the animal fats in waste...the contacts can't make contact or maybe so clogged up they can't move. The only cure: pull out the senders and soak 'em in a STRONG solution of detergent degreaser to dissolve as much as it can, then finish the job manually with a brush. Which explains the growing popularity of systems that use external senders.

[SaltyMetals]

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?