My tap water in incredibly hard, TDS 400+. I have an RO unit for my aquariums.
My question is: Pure RO water is not safe to drink on its own or cook with, it actually sucks minerals out, but I want my guinea pigs to have less calcium in their water. If I cut the tap water with half RO, would this work? Or are there any mineral supplements which can be added back in to the filtered water (essentially, this is what I do for my fish tank, take the minerals out and then add back in the correct ratios with a special powder designed for fish)
Charcoal filters like Brita etc don't work to remove the calcium levels, only chlorine.
Thanks in advance!