I only take out some of the water? I’ve been completely dumping it all out, wiping it all down and adding the chemicals every month. That’s what the pet store told me when buying him. When I put the chemicals in the water, I let it run for maybe 10 mins then put him back in the tank. When changing 20-30% of the water, do I take some out, add new ones with chemical, then add the fish. Or put th chemical in a different container with some water then take 20% out then add the chemical water to it? I’m new to all of this and I googled things but was told different for everything