Reducing pH and GH in a stocked tank
So I have a tank with a few Neos and a couple of chili rasboras, with a shipment of Neos on the way. I decided I'd like to add a few tigers eventually, so I need to lower the pH and hardness from 7.6-8 and 8 to something around 7.4 and 6. I plan to do that by mixing DI water with tap.
The incoming shrimp will be stressed enough from shipping, so the biggest reduction step should take place before they arrive. The question is how much can I lower it without harming the existing inhabitants?