Clean Aluminum water tank...full of scale

S

sunnydude2

Member
Joined
Feb 10, 2005
RO Number
16265
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25
We just bought an 1987 boat from California and brought it to the PNW. I know the previous owner let the boat sit for the past year but not sure about prior.

Here is my problem. The water level display was not working. We have great access to the sender so i remove the 5 screws and pull the sender out. No arm is connected and crap is all over the unit. Look in bottom of tank and it is covered in scale (whitish hard stuff). Stuck a screwdriver down and scraped some off the bottom. Started draining tank. Now I need to get the stuff out. What can I use in a metal tank to dissolve or loosen this stuff? This might explain why the water pump trips the breaker as there is also no filter between the pump and the tank.
 
Is this a holding tank or fresh water tank? I ended up having to replace both my aluminum water tanks and my aluminum holding tank and replaced them with Poly/plastic tanks. They were leaking from corrosion and stunk. I'm not sure I would have used the water to wash my hands they were that discusting. The poly tanks then allowed me to use the Raritan water gauge system where there are no moving parts in the tank.

Bill
 
You can use a couple of things, acid will dissolve the crud, but can damage the tank if left in very long. Sno-bowl toilet cleaner is about as strong of acid that I would use. leave it in for 5-10 minutes at the most. rinse tank multiple times.
You might be better off starting with a mild acid like vinegar. They use vinegar to clean commercial coffee pots.
Another option is CLR, but due to the price, size of tank, might be cost prohibitive.

After thinking about it, start with the vinegar. drain the tank before starting. If needed use a wet-dry shop vac to remove the water and any loose chunks. pour in enough vinegar to cover all corrosion/gunk. Let it sit for several hours, drain, check results. The old vinegar can be reused to continue the cleaning if you strain the gunk.
 
quote:
Originally posted by BarrenRiver

If you got the sender out, you should have no trouble getting a garden hose in...so maybe something like this at camping world might work for you...
Click to expand...


This is what I was thinking.

The tank is just my fresh water tank. No leaks and a pain to remove if had to. Might try the vinegar and the wand, that sounds like a pretty good idea.
 
In my case I did the vinegar clean then small amounts of bleach back and forth and pressure wash but eventually the corrision killed the tanks. Mine were previous owner's neglect the boat sat in the water for 2 years with the holding tank full and the FW tanks were about half full.
 
Chances are that the white hard stuff is part of the aluminum and not stuff from the water. I fought this problem for about five years until the tank finally leaked. Tough to remove but once I got it out I found that a good 50% tank was so destroyed that I could just push a screwdriver thru the metal. I would suggest you start planning for the replacement and in the interim do not use anything except fresh water or you will accelerate the time to failure.
 
I agree with everything Happy Hour said - and don't use anything stronger than vinegar in it, or you'll likely wind up with a colander on your hands. If that tank is original to the boat, I'd start planning for it's replacement; it's over 20 years old, and the normal lifespan for an aluminum water tank is around 12 years (7 or 8 years for a sewage holding tank) - so it's certainly due for replacement...! And when the time comes to replace it, you'd be best advised to use a heavy wall polyethylene tank, rather than metal of any kind.
 
Vinegar is going in the tank tonight. Cleaning out tomorrow. will try to get a picture of the gunk.
 
The bleach definately helped do my tanks in but they were so unsanitary I needed to try and disinfect them. In the end I had them replaced like Vic says with thick walled polyethylene tanks.
Now I keep them clean by using and flushing them on a regular basis. Mine were 13 years old but abused before I got the boat and then after I tried the bleach even though it was highly diluted.
Bill
 
The tank wasn't in that bad of condition when I got into it today. Used a piece of conduit (plastic) with a weight in the end and moved it around the tank. Drained. Added new water and did again. Shop vac'd the water out and into tub. Poured vinegar into a full tank and it is still sitting in there as the fitting connecting hose to pump broke and I was out of boat working time. Back tomorrow to drain and flush with fresh water.
 
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