I haven't tested my water in a bit because I've been performing regular water changes and my fish have been healthy and happy. I have a 150 gallon tank and I recently added 3 angel fish (1 being about 3 inches) to my stock. When I got home last night the big angel was dead and the other two were missing. I tested the water and the parameters seemed ok, but the PH spiked to 8.4 from about 7.8. Ammonia was 0ppm, nitrites 0ppm, nitrates 10ppm. My concern is with the PH being in that range I don't want it to start effecting my clown loaches. Any suggestions?