Organic growth in fresh water tank

[spudthegreater]

Was working on changing the resistor pack on my fresh water tank probes and ran into something interesting. I have my tt in a large Metal Quonset hut so its pretty dark underneath the trailer and taking a fairly bright adjusting led light with me I noticed that i could see shadows of somekind through the white opaque water tank. I put the light close up to the tank and realized this had to be organic growth of some kind, tannins or algae bloom or something on the inside of the tank which at this point was full of water to help test my probes. Now, We don't drink this water, we just purchased this Jayco 20bh this year used. So i took it out and dumped the water and added appropriate bleach/ water mix in a gallon container then funneled it in and filled the tanks. Then proceeded to get some chlorinated water through the system. I have left it in for several days at this point simply hadn't been able to hook up and remove outside yet. Decided to finish my probe project and now the shadows are no longer dark they are very light brown/tan in color making me think the algae is now dead which a week later certainly should be. The hot water tank is currently outside on a work bench undergoing refit, so no chlorinated water in that part of the system. Has anyone ever noticed this before? I wouldn't have, had it not been so dark and had a bright light shining onto the tank bottom

[SkyBound]

I bleach my tanks each and every year, and never leave them sitting full for more than a day or two. I have never run into this before, no. Regardless of how clean the fresh tanks are on a trailer, I do not drink the water from the tap.

[muckinfuss]

You may want to connect and tow for a few miles. Break up the sludge of dead stuff so it can move through the system easier, plus it should provide a splash of bleach water onto any interior that may have missed the soak.

[Camper_bob]

I have that exact situation in my tank right now.

I'll admit, I have not been "judicious" with tank and line sanitation. I'm pretty sure if I were, I would not be having this issue.

My intent is to do several bleach cleanouts to get as much dead and out as I can and move forward as best I can. Making sure I do at least 2 cleans per year.

The trouble is that the bottom of the tank is a little "bowled", so it's just about impossible to remove all of the water from the tank. Plus it will sit stored outside in the hot Texas sun for sometimes months at a time. So I fear I will be fighting this issue as long as I own the rig...

We don't drink that water either, so I don't think it poses much of a "health" problem, but if it continues unchecked, there will be other issues.

[Midnightmoon]

This is just my method and not necessarily a recommendation. But, when I sanitize my system, I leave the bleach mix in the tank for extended periods of times, sometimes as long as a couple of weeks, and then thoroughly flush before we use the trailer the next time. I will do this at the beginning and end of the season and then after every time that we fill from a non-public water source (campground well, spring, etc.)