Cleaning water tanks

[Dick Behan]

We've recently bought a 24 year old Pacific Seacraft Flicka. The stainless water tank has a lot of black slime in it. A vigorous stream of water seems to loosen the stuff and we can pump out the flakes and pieces. But the tank no doubt has one or more baffles, so we can't remove the slime from the entire tank with the jetting water. Does anyone know of a solvent or some sort of (benign) chemical that might clean out the tank? Thanks a million.

Dick Behan
S/V "Rowdy"

[cabo_sailor]

The question of sanitizing tanks has come up before. When it did I saved the following links. Hope they help.

How to Sanitize Your RV Fresh Water System

www.sailingtalks.com - cleaning water tank - For Peggie Hall

Good luck,
Rich

[thinwater]

Originally Posted by Dick Behan

We've recently bought a 24 year old Pacific Seacraft Flicka. The stainless water tank has a lot of black slime in it. A vigorous stream of water seems to loosen the stuff and we can pump out the flakes and pieces. But the tank no doubt has one or more baffles, so we can't remove the slime from the entire tank with the jetting water. Does anyone know of a solvent or some sort of (benign) chemical that might clean out the tank? Thanks a million.

Dick Behan
S/V "Rowdy"

A pressure washer with a flex-lance can work, but requires great care to avoid injury. Look on the web for safety rules. Attaching a length of smaller hose to the end of the garden hose can work too.

[CarlF]

Sandy Dauherty recommended a product called Orange TKO to clean a water tank that had diesel in it. I've tried it and found it useful for many things including mildew removal. You can mix it in different strengths. Google Orange TKO for more info.

If you use bleach, be very careful of the fumes. It can burn your lungs easily.

Carl

[Tropic Cat]

A few years ago I took a 2 gallon jug of pool chlorine (double strength) and dumped 1 gallon in each of my 35 gallon SS water tanks and then filled them with water. I left it in there 24 hours and then drained out the crud. The good news, it seemed to clean them very well. At the very least it killed anything growing in there as well as anything crawling or flying by the fill pipe.

The bad news, it took about 10 - 15 flushings of each tank to get the chlorine smell out of the water. After all I had 1 to 34 chlorine mix. For a pool, the chlorine level is measured in parts per million.

As an aside. There was a water leak problem this past weekend in an Endeavor Cat docked next to me. The repair guy had to saw through a fiberglass bulkhead to get to the tank and then saw the aluminum water tank open as there was no access hatch and no access in the compartment to inspect the bottom of the tank. He discovered that aluminum oxide covered everything on the inside of the tank. He was there for an entire day scraping and cleaning the inside of that tank in order to discover the leak.

I took a peek inside the tank as he was working and just shook my head. No aluminum water tanks are in my future.

[sailorboy1]

Wow Rick that was a lot of chlorine. I added 4 oz of bleach to each of my 40 gal tanks the other day. And since I am in the water treatment business did a chlorine test on them afterwards. The 4-oz in 40-gals was enough to fly right off the scale.

[Dick Behan]

Thanks, everyone, for your interest and your knowledge. I'll take it from here--and offer a cool tall one to anyone here who shows up on "Rowdy" some fine day.

Best,

Dick

[Tropic Cat]

Originally Posted by Don Lucas

Wow Rick that was a lot of chlorine. I added 4 oz of bleach to each of my 40 gal tanks the other day. And since I am in the water treatment business did a chlorine test on them afterwards. The 4-oz in 40-gals was enough to fly right off the scale.

Actually Don, you're right. It was my ignorance. In retrospect I should have done my homework first. I'm fortunate that SS tanks handled my improper use of chlorine so well.

OTOH, my tanks got very clean, very fast.

[S/V New Sensation]

OK I must be different (my wife tells me so), I've added clean outs to both fuel and water tanks on every boat I've owned. I added a second cleanout where needed to reach beyond baffles. Although using chlorine works great to kill I still like to get into those old tanks and clean out the gunk. On my present boat I've used the "Seabuilt" access plate systems that fold in half for easy installation and so far they have worked well for me (expensive but very easy to install and seal). Makes me feel good to know the tank is not only sanitary but also clean. Agree about aluminum water tanks (although never seen a problem with diesel aluminum tanks) I'm very glad I have stainless steel as friends with aluminum always seem to be chasing "the white stuff".