I can't fully agree with the thought that things can't be worth adjusting a bit. It is good not to make large changes but tanks do change even when the don't see it. That requires being ready to change small things.
One thing I would first look at is the water used. To cut the amount of hassle and expense, I'm pretty sure you can switch to regular tap water and use a product to deal with the chlorine and any metals. Prime is a favorite with many people that is easy to use and deals with both problems.
You may have a really special situation but for many people all around the world, adding a bit of dechlor is much better than buying water to drag home.