I am having a problem with low ph (7.8) and alkalinity (4.5). Water movement on the surface is good and ammonia 0 nitrite o nitrates less than 1. I have a 55 gal. tank with live rock and base rock.1 fire shrimp, 2 clownfish,1blue green chromis,1clown goby,1purple firefish and 1 flame angel.I...