Re-conditioning water tanks

[Tom51]

I'm in the process of cleaning the water tanks in a six year old sailboat we just acquired and I was wondering what the heck that brown stuff is on the inside walls of the tank. Is it necessary to completely remove all that stuff by scrubbing or is a treatment available that will do the trick. Don't plan to drink the water but I'd like it to be safe. Any ideas????

Tom

[swagman]

Id' suggest the brown stuff is an algea and whilst it may not do you any harm - its more easily removed with proprietary products than a scrubbing brush.
Most chandlers will sell you a small tub of chlorine based cleaner which you can mix with water in the tank - leave to stand for a period so it kills the algae - then flush out.
We add a teaspoon of such cleaner every time we fill our 360 litres - and the tanks stay clean all the time.
Cheers
JOHN

[colemj]

If you have aluminum tanks, do not add chlorine based cleaner on a regular basis. Shock treatment will probably be OK, since it will be short term, but you will want to be sure to rinse the tank very well. You might want to be careful with regularly using chlorine on stainless tanks also. Chlorine is very corrosive and will eat at aluminum.

John is correct that the brown stuff is most likely algae. The chlorine cleaners will kill the algae, but I suspect you will still probably have to do a bit of scrubbing to get it unadhered from the tank walls.

Mark

[Talbot]

Always amazes me when people make comments which indicate that the condition of the water from their tank is not exactly wonderful.

It only takes a bit of effort at the start of each season plus a a tablet per fill up, follwed by a decent in-line filter such as the Jabsco, and the water from my main drinking tank is better tasting than what comes out of the tap at home! makes great ice, and complements a good malt.

[DeepFrz]

If you have "brown stuff" on the inside of your tanks you have it on the inside of your hoses as well.

Many people believe that it is good to have an air filter on your tank vent so that you are not sucking in dusty air while using water. Sounds plausible to me.

Deep.

[Tropic Cat]

I cleaned mine using swimming pool chlorine. It's twice the strength of house hold bleach. A 2 gallon container cost about $6.00. I used 1 gallon in each of my stainless steel 35 gallon tanks and left it in for 24 hours after filling them to the absolute top. I then proceeded to pump it out using the whale foot pumps in my head and galley. This took forever, but all lines and plumbing were algae free when I finished.

If I had to do it over again I would use 75% less bleach. I had to flush the tanks repeatedly after the treatment to get rid of the chlorine smell.

Rick in Florida

[Talbot]

Cheapest way - Get Chloramine from Chemist - make up a 2-5% solution and fill the water tanks, leave for 24 hrs.

Rinse out thoroughly

[kushka]

If the "brown stuff" has been there for a long time without being cleaned it may be really hard to get out. Filling the tank with ice and going sailing may scrub the tank pretty well.

The hoses are a different story all together. If they are clear the light promotes growth of algae. My boat sat for a long time before I bought it, and I don't think any amount of cleaning could have cleaned out those hoses.

[Alan Wheeler]

OK, from a different approach angle. It is also possible the "brown stuff" is not algae. It could be that a Iron rich water has been the common tank fill. The brown stuff maybe Iron stain. A simple check is required. Is the "brown stuff" slippery gunge on the tank wall??? yes? then it's algae. But most unlikely as Algae requires light to grow. Is the "brown stuff" a hard stain like. yes? then it is a stain from the water such as Iron. This could be easily cleaned off using a rust converter liquid on a rag, such as Jenolite or CLR or similar.

[Pblais]

Algea can't grow in the dark - period. It's a plant after all. If you check out Peggy Hall (head and water fame) she promotes a lower concentration of chlorine for the 24 hour shock treatment. It really does not require much at all to kill any and all critters. Over chlorinating has no extra benefit other than eating at your plumbing. You plastic hose really would prefer a lower dose. One cup household bleach per 100 gallons is enough.

Mineral deposits could be common in tanks after a prolonged use from hard water and the chlorine won't really reduce it to any significant extent.

CLR is poison.

You can rig up a household two stage filter that you connect to the water supply line with some washing machine hoses so you filter the water before you put it in the tank. That is a more proactive approach to keeping the tank cleaner and promoting better tasting water. What never gets in won't ever give you trouble.