Attack of the Blob!

[BrentB]

I know there are many threads about how to sanitize tanks, and I have done that, but I still have a problem. While using my water pump, water would flow ok for a while, then slow to a trickle and stay there. I finally discovered that the pump filter was clogged with algae. I cleaned the filter, but the same thing happened again, so I decided to take a look in the tank and found that there are large chunks of algae in there.

This gunk is not fazed by bleach, even at 200 ppm, and is too big to drain through the tiny 3/8 inch drain hole. I would love to scrape and scrub the inside of the tank to get rid of it, but of course the problem is gaining access. My first thought was some kind of access port, but I am having difficulty finding something that I think would work.
I found this, but it seems too small: https://www.marinesan.com/Holding-Tank-3-Clean-out-Kit-p/307238685.htm
I found this, but it seems too large: http://www.hendersons.co.uk/boattank/Tank-access.html
And I’m not sure if either will withstand the pressure of being submerged. (There is no access to the tank from above.)
I also thought of installing a larger drain fitting, hoping that the gunk will drain out, but I see that the spin weld fittings require a router, not a drill, and I don’t want to buy one of those. The only access to the tank is from the bottom or one end and the tank is about 4-5 feet long.
I just ran across this, not sure if it would work to build a larger drain: https://www.usplastic.com/catalog/item.aspx?itemid=89951
I really want to clean the gunk out without removing the tank as that is not easy to do.
Does anyone have any other solutions that I haven’t thought of?

[BrentB]

CavemanCharlie wrote:

BrentB wrote:

CavemanCharlie wrote:
Where are you filling your tank from ?? A well may have more contaminants in it then a public water system causing the problem to come back.

We have that problem on our outside tank that we use for filling the agriculture sprayer but, it sets outside in the sun. I've never seen a tank in a TT that bad because they are mounted where it's dark.

I fill from a city water supply, and have for years, but I am the second owner and don't know where the previous owner got his water. The bottom of my rv is not enclosed, so the tank gets lots of indirect sunlight.

Both of those could be part of the problem. Is the tank white so that light gets though easily ? I wonder if spray painting it black would help to keep light intrusion down ?

Yes it is white. Thinking about painting it. Here's a photo showing the amount of sunlight inside, as well as the gunk at the bottom.

[CavemanCharlie]

BrentB wrote:

CavemanCharlie wrote:
Where are you filling your tank from ?? A well may have more contaminants in it then a public water system causing the problem to come back.

We have that problem on our outside tank that we use for filling the agriculture sprayer but, it sets outside in the sun. I've never seen a tank in a TT that bad because they are mounted where it's dark.

I fill from a city water supply, and have for years, but I am the second owner and don't know where the previous owner got his water. The bottom of my rv is not enclosed, so the tank gets lots of indirect sunlight.

Both of those could be part of the problem. Is the tank white so that light gets though easily ? I wonder if spray painting it black would help to keep light intrusion down ?

[BrentB]

CavemanCharlie wrote:
Where are you filling your tank from ?? A well may have more contaminants in it then a public water system causing the problem to come back.

We have that problem on our outside tank that we use for filling the agriculture sprayer but, it sets outside in the sun. I've never seen a tank in a TT that bad because they are mounted where it's dark.

I fill from a city water supply, and have for years, but I am the second owner and don't know where the previous owner got his water. The bottom of my rv is not enclosed, so the tank gets lots of indirect sunlight.

[CavemanCharlie]

Where are you filling your tank from ?? A well may have more contaminants in it then a public water system causing the problem to come back.

We have that problem on our outside tank that we use for filling the agriculture sprayer but, it sets outside in the sun. I've never seen a tank in a TT that bad because they are mounted where it's dark.

[hawkeye-08]

Middle daughter bought used trailer that had been sitting for several years and had the problem you have. She filled and emptied several times, then bleached it and let sit overnight, drained, filled, drained, filled, bleached, let sit over night, drained, filled, drained, filled.. bleached again, let sit several hours, drained, filled, drained, filled. She also cleaned the filter on the water pump a number of times. They carried drinking water in 5 gallon water jug then. I don't know if they got the algae completely out or not.

When we bought our used trailer, it only took a couple of treatments to get rid of it, only had to clean pump filter a few times. No problems since.

[BrentB]

Lynnmor wrote:

BrentB wrote:
Yeah I'm tempted to just replace the tank, but what if it comes back?

If you have this type of water fill, please note the algae insertion port to the bottom left. I really don't know how they get away with installing something that lets anything flow directly to the fresh water tank.

Yeah, that's what I have. That could well be how it got started. The tank is always exposed to outside air via the vent tube.

[BrentB]

2012Coleman wrote:
How did you get the picture?

Borescope through the fill inlet.

[BrentB]

2012Coleman wrote:
Try the pool chlorine idea. Put some water in it and then dump a 1/2 gallon of it in there - that may be overkill as it only takes 2 gallons to shock my 15K+ gallon pool. It wont hurt the plastic. Then follow that standard procedure to sanitize the water system. Someone it seems, never drained the tank using the low point drain. How did you get the picture?

I have drained the tank many times, but the hole is only 3/8 inch, so this stuff won't drain out as is. Will the pool chemicals dissolve it? Previous owner may have used well water, I don't know.

[Lynnmor]

BrentB wrote:
Yeah I'm tempted to just replace the tank, but what if it comes back?

If you have this type of water fill, please note the algae insertion port to the bottom left. I really don't know how they get away with installing something that lets anything flow directly to the fresh water tank.

[Bobbo]

Replace the tank, then disinfect the water system regularly.

If you are on chlorinated city water, disinfect the tank if it has been a month or more since it was last used. (This means you will disinfect it when de-winterizing every year.)

If you are on a well (non-chlorinated water), disinfect the tank every 4 to 6 weeks regardless of whether it has been used.

[2012Coleman]

Try the pool chlorine idea. Put some water in it and then dump a 1/2 gallon of it in there - that may be overkill as it only takes 2 gallons to shock my 15K+ gallon pool. It wont hurt the plastic. Then follow that standard procedure to sanitize the water system. Someone it seems, never drained the tank using the low point drain. How did you get the picture?

[BrentB]

Yeah I'm tempted to just replace the tank, but what if it comes back?

[GrandpaKip]

That’s algae and without a way to get into the tank, it’s going to be hard to get it all out. That stuff gets into my water storage tanks that I have for vegetable gardens. I gave up cleaning them, but it’s not for drinking.
Even when it’s all dead, sheets of it remain.
I’d be very tempted to replace the tank and be done with it.

[BrentB]

Thanks 2012Coleman