You actually want your pH a bit higher. What are the actual numbers on your other tests?
What are you feeding? How long are the lights on? Can you turn off the powerheads and do Max's (a mod here) trick of dropping in a bit of milk and then turn them back on to see if the flow is good and chaotic or if there are any dead spots?
What are you feeding? How long are the lights on? Can you turn off the powerheads and do Max's (a mod here) trick of dropping in a bit of milk and then turn them back on to see if the flow is good and chaotic or if there are any dead spots?