Hello, I have finally completed my setup and ran into a problem. I have a dirted 75 gallon tank on top of my stand, and an undirted 40 breeder below it. The 75 overflows into the 40 which overflows into a 10 gal sump on the floor which is pumped back to the top. This has been an idea of mine for about 6 months. The top tank is fully planted with 4 otos and 4 rosy red minnows. The bottom is black sand with my 3 original (huge) amazon swords, a bn, a 1 year old angel, 3 neons, and 1 cory. I was about to finally turn the pump on for the first time when I decided to make sure the ph matched. it didnt. I have been doing 5 gallon daily water changes in both tanks for about a month. The 75 read about 6.8 (api master) and the 40 read 6.0 (could be lower, 6 is the lowest on chart) I'm completely stumped as to why the ph is different. same water change schedule, the other difference is the 75 is more heavily planted and dirted (which if anything should make the ph LOWER) Any body have any ideas as to what I should do? should I just turn the pump on and let the ph stabilize within the system and hope all the fish make it through the process?