Lowering alkalinity raises TDS - What is it?

[chem geek]

Since the TDS you would add to your aquarium is essentially salt (as calcium chloride and sodium chloride), then you should look at this as simply adding salty water to your aquarium (i.e. adding salinity). Obviously, if your aquarium is already salt-water, then this should not be a problem, but if it is fresh water, then the salinity may not be good for plants and fish and that seems to be the primary issue here.

It is not easy to remove the resulting salt as you would have to do something like reverse osmosis or distillation to do that (like a desalination plant). You could also change the calcium to sodium using an ion exchange resin as found in water softeners if calcium where a problem. Probably the easiest way for you to get purer water for your aquarium is to buy distilled water or at least bottled water which should also be low in salt. I suspect that it might not be that much more expensive given how much it would cost for you to do your own "pressured" reverse osmosis or "heat" distillation.

Richard

[aquarium]

Thanks Richard!

A little bit of salt is okay. I have a reverse osmosis system that I use for evaporation replacement water, but it's looking like this is the easiest way to make larger quantities of aquarium water. My apologies for going off-topic poolwise, but the water parameters issues are similar.