Hi. I need your help please!! Don't know what to do. My cichlids are swimming on the top gasping for oxygen. I have an air stone and wave maker. Water test, amm-0, Nitrate-40, Nitrite-0,Hardness-25(very soft),Chlorine-0,Alkalinity-180,PH-7.8,Temp-82. Thx in advance. Did 25% water change...