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 the result is what you see in the photo.
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-Ta.../307238685.htm
I found this, but it seems too large: Access Panels|tank|hatch|boat|water|TCL4
And Iím 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 donít 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/it...x?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 havenít thought of?