Hi. So happy to have the chance to post this question. I am a beginner. My 12 year old is really into learning about fish and I’ve joined him. We are starting with a 20 gallon tank and going to learn from this before we jump up in size. The issue is We live off of a limestone aquifer well. Our water is liquid rock. It eats valves in our pipes. We have a decent water treatment system with softener and an RO filter. I can draw from any of these sources. I know well water is ideal normally but I tested my gh and kh for hard and soft water Hard water gh is well over what the API Max is at 320. Kh is well over max also. Once the water goes through the softener gh is reduced to almost nothing but kh remains the same. I have a lot of differing advice from fish stores and I know I shouldn’t put African cichlids in a 20 gallon. My hard water parameters look like brackish water if anything pH is consistent around 8.0 Which isnt a problem. My question is what water to go with? I’m open to whatever fish work best for the water and tank size.