“Sand in Water Filter

[Sevi]

Hi All-

I found what looks like sand in a filter between my aluminum water tank">fresh water tank and the fresh water pump, which I suspect may be aluminum -calcium salt which has precipitated out of solution. Does that mean that my tank should be replaced (maybe with plastic), an expensive proposition, or merely inspected?

Thank you in advance for your help.

[Sailmonkey]

Or just maybe, you've got sand in your water tank?

[a64pilot]

It could also be just calcium from hard water.
I have the same, and hope it’s calcium. I have a filter inline with my water pump to filter all of the water, but 99% of this “sand” is caught in the pumps pre filter screen.
Do not use chlorine in your water tank, ever, or you will be replacing it.
Expense is largely based on what it takes to get the old one out. I have an estimate of $20K to replace both my fuel and water tanks, but the whole interior sole has to be remove in my case

[huhns]

Almost all municipal water contains chlorine, which reacts with your aluminum tank to produce crystals of aluminum chloride. They look like sand and are white, although the presence of a little iron can turn them a light yellow. Their occurrence is very common in boat fresh water systems. Your filter will trap most of them, so they are not generally a concern. The crystals that get past the filter can clog your faucet strainers, but this is a minor annoyance. Over time, however, the aluminum will be eaten away and leaks will develop in the tank. Until then, you don't need to do anything about your tank, but you might try to minimize the amount of chlorine that gets in it by using activated carbon filters (or similar) on the water you put in it.

Mike