Tank Gauges

[Matt sachs]

I have seen them, so I know they exist, but I can't remember the name. It looks like a verticle lenght a tape on the out side of the tank that changes color at the fluid level inside. Can someone tell me what its called so I can google it?

[HopCar]

I've seen tapes like you describe but only for use on propane tanks.
Is this what you are looking for? Magnetic Propane Tank Gauge - Lee Valley Tools

[Lancerbye]

Hopcar is right. The stick on or magnetic tapes that are used to measure level on propane tanks are basically a temperature activated strip that works only on propane tanks because of the temperature change at the evaporating liquid level of propane.
Look up Tank Tender for a multi tank measurung system. Works on a back pressure measurement which can be converted to the actual quantity in the tank. Very simple and uses no power.

[Play Actor]

Nothing beats a dipstick or a sight glass for simplicity and accuracy. I finally got there after years of fussing with a Tank Tender, which did work, but sometimes produced odd results. Never figured out why; it's gone now.

I use a 1/4" dowel marked in inches for the diesel tank, and a sight glass made from 3/8" vinyl tubing for the water tanks.

[anjou]

Ive got clear PVC tube for one water tank but its slowly turning black inside. The water here is very hard with a high concentration of limescale. I dont think its lime though, looks more like a mildew

[Play Actor]

We have only rain water in our tanks, so it's very soft, and we still get the black discoloration. Pretty sure it's algae growth. I made a swab of a length of monel wire about six inches longer than the sight glass, with a 1/8" loop in the end. I put a 1 inch square of soft cotton cloth through the loop and use it to clean the inside of the sight glass when it gets too dark to see the level easily -- once every couple of months. I just wait until the level is below the top and pull the tubing off the barb, swab it, hold the open endof the tube lower than the liquid level in the tank and let it flush itslef into a container. I lose a few ounces of water, but it's good for another couple of months.

[landonshaw]

Interested in the sight glass tube for your water tank. I understand the sight end, how did you attach the other end to the tank? Punch a hole the bottom of the tank, attach the tube, then seal?

[Play Actor]

No new holes were required. I have two water tanks that are connected through a valve manifold. I put a "T" in the common line from the manifold, which is below the level of the tank bottoms. I connected the sight glass to the "T." It reads whichever tank is in use. Most of the time we have the tanks tied together, so the level in them is the same -- they are on the same level -- one on each side of the boat.

It's important to note that the top of the sight glass must be open in order to work. To avoid losing water from it when we're heeled, I connected the top to the vent line on one of the tanks.

[landonshaw]

Thanks for the response. I do not have two tanks but there is a line that goes to the water pump that I could come off with a T. Run that hose up along the wall for a good sight.