Canoe building plan

Holding Tank Level Monitor

 I wrote previously about Gobius Tank Level monitoring. You can review that blog here.
On my forward holding tank, there is no way to easily place an inspection hatch for level monitoring (as per my previous blog). That is because to get at the tank, I have to remove a heavy mattress and covering board to see the tank. We also use the forward berth a lot, to store our extra equipment and sometimes supplies. So it can be a real hassle getting to the forward tank.
We use to empty the forward tank whenever we emptied the aft tank; but that was a
waste of tank treatment if the tank was say only 1/4 full.
So for me the solution lay with this new tank monitor device. You can see in the three photo's, the installation of the three main components of the device. The level indicator was placed just over the head electrical switch. The "computer" was placed on the side of a locker, next to the holding tank and the sender unit on the side of the tank as indicated in their web site tank calculator. Everything was easy except the sender unit. I followed their direction to the letter, but it would not stick. Sanded level, made sure tank surface was above 20 degrees C, and wiped surface prior with their special towel. Didn't stick! They supplied a spare sticky patch with the kit, so I tried the spare. Still no stick! So I wrote to their support email and two days later got a reply. The insinuation was that I had not followed with their directions
but they would post a new sticky patch out to me. Well, that wasn't going to help much, being on a boat, "cruising the world". So I took matters into my own hand. This they didn't recommend, but I did it anyway. I sanded the sticky patch that wouldn't stick so that it had a rough surface. Next I applied a very thin layer of 3M 4200 and applied the sender unit to the tank. I had duct tape ready to tape this unit to the tank until the 4200 set up. Next morning, the sender unit was attached "rock solid" to the tank. I proceeded to change the default settings and calibrate the unit as per their directions. And the unit works great. I may at a later date put a buzzer in the analog circuit which is detailed in their instructions. In the mean time, the 3/4 warning light comes on when the tank is 3/4 full. You can add extra sender units to have a 1/4 and 1/2 level light as well, but I'm very happy with this at the moment.