So everything was going well with my tank until one fish eventually got ich and within days it destroyed all the fish. It’s been a month since then I still have my snails crabs and shrimp. They are all fine. My question is do I have to drain my entire tank? I have been slowly letting the water evaporate and planning on doing a big water change. Is this enough. I don’t know what I did wrong. I use rodi water have a protein skimmer do not over feed. Sucks all that money and work down the drains. Would like to try again just nervous now. Any advice would be great. Thanks