water tank gauge

[RejoiceWay]

The four colored indicator lights for the fresh water tank all "light" when the switch is depressed--even though there is no water in the tank. Any idea on how to trouble-shoot this?

If this was happening with your gray water tank it could be debrise on the inside sensors. I doubt you have debrise on your fresh water sensors, but they may be loose.
Locate your fresh water holding tank and check to see that the wires are secure and connected, not broken.

[Wavery]

It could also be caused by "Slime" build-up inside the tank. You might try putting 1 gallon of bleach for every 10 gallons of water in the tank, fill it up with water and let it set over-night. Run the water all through your sytem (hot and cold), then drain it out.

Add about 15 gallons of fresh water and drive around the block a few times to slosh the water around real good. Dump it out. Fill the tank, run the fresh water through the lines. Do it twice, if it makes you feel better......

The bleach will sanitise your water system and disolve 100% of the slime and mold. A 10% solution won't hurt anything in your water system and once it's flushed out, leave the cap off the tank (cover with screen or cheese cloth to keep critters out) for a few days and it will be better than new. The risidule clorine (if any) will probably be less than what is in your city drinking water.

I did this every year on my yacht for 14 years (30 gallons of bleach in 300 gallon water tanks). I do it every year on my TM as well.

I have always used about 1/4 cup per gallon of capacity. Run all lines then top off tank with more water/bleach.
Another way is to use VERY CONCENTRATED chlorine used for swimming pools and hot tubs. This stuff leaves less after taste and only takes a pinch.
Always add water then bleach and then water to finish.
Try googleing "sanitize water tanks with bleach" for some more information.

[RejoiceWay]

Thanks for all the hints! I am working on it now. I will give you an update on Monday.

[RejoiceWay]

Wow - flushed the freshwater tank with bleach water and the problem has been solved. Thanks to everyone who posted solutions. The gauge now shows empty when empty and we also know we will have clean fresh water next time we fill the tank. We really appreciate all the advise from this forum.

[Wavery]

Originally Posted by RejoiceWay

Wow - flushed the freshwater tank with bleach water and the problem has been solved. Thanks to everyone who posted solutions. The gauge now shows empty when empty and we also know we will have clean fresh water next time we fill the tank. We really appreciate all the advise from this forum.

The problem with all RV water tanks is that the supply line going to the pump and the drain line are on the side of the tank (as apposed to the bottom). This means that when you "drain" your tank, it's never really empty. There is still about 1/2-1" of water in the bottom of the tank. That means that the tank is never "dry". In that wet environment, there will be slime build up on the sides of the tank over time (while in storage). That slime conducts electricity just like water does.

It helps to add about 1/2G of bleach to a tank full of water while your trailer is in storage and store with the tank full. You can dump the water before you go camping and fill with fresh either at home or when you get close to your destination (as we do, to cut down weight).

search for my earlier post on adding a marine deck port to the top of the tank. It creates a water proof 5" clean out port you can get your arm through. I also allows you to use a wet dry vac to totally empty the tank if it will sit for a while. I would not recommend using pool chlorine tabs or powder to clean the system as it uses a binder to make the tabs or powder and this can gunk stuff up