My system background is 30-gallon planted tank, Fluval blue tooth light, Fluval 307 filter, heater, CO2 tank, and air stone. Fish are 12 glowlight tetras, 8 neon tetras, one male beta, and I had 6 orange shrimp and 6 red shrimp. I am now down to 4 shrimp total. I tested my water with the API freshwater test kit and my results are as follows: Ammonia 0 ppm, Nitrite 0 ppm, Nitrate 0 ppm, and my problem pH 6.5. I use API's liquid pH Up with not much success. So why are all of my shrimp dying? All of the rest of the fish are fine. The rocks as pictured below, are from the Vermont mountains near the Connecticut River. My suspicion is that the mineral content of the rocks is keeping my pH low. Any advise and explanation would be extremely appreciated. Sincerely, Ed Gibbs