We tested the water from a jug after a day the ph hadn't gone up, just seems to be in the tank. I have quite a few fish in the tank so really need to get this sorted, 2 cat fish, 2 glass catfish, 10 guppies, 10 mollys, 5 neon tetra, 5 black tetra, 5 danio's, 2 flying fox's, 2 pleco's, siamese...