How long had the lights been on when you tested? If you test soon after
lights on you'll get a low result - just before lights out and it will be
higher. As long as the lowest result you see is about 8.0 or higher and the
highest is 8.5 or lower don't worry. Keep the Alk up and the pH will simply
fluctuate within an OK range caused by photosynthetic processes in the tank.

Mark

"Mark Fitzsimmons" wrote in message
...
Running a reef aquaium... Did some water tests today with the following
results.

Alk is high and the Ph is slighlty on the low side - How do I remedy this
please?

Also, I'm trying to promote coraline growth on the rocks, apart from
seeding
the tank with small rocks that have already have good growth on them, good
circulation etc, what else should I do?