I have a 600 gallon system and in one week I have had to add ~70 gallons due to evaporation. The water around here is kind of hard and we get severe calcium deposit build up on everything. I an even noticing a film building up on my clay rocks too. I was wondering if this will be a problem with the water evaporating and possibly building up a high concentration of deposits left behind in the system.

I thought doing periodic water changes will help solve the problem, but kind of a nuisance. I also saw this dechlorinator http://www.amazon.com/Rainshowr-GG-2...+dechlorinator and one of the user comments was that it also removes calcium and magnesium (???). Not sure it is an accurate statement or not, but if it is maybe it would help. Or would it deprive my plants of those nutrients?

Anyone have any ideas if this could be a problem and ideas for solutions. Thanks all.