You definately have an issue going on. Natural pH of seawater runs from 7.5 in the open ocean to 8.4 in reef areas with the average being 7.8, according to the book "The Concientious Marine Aquarist" by Bob Fenner. pH should be kept high at around 7.8 to 8.4
Most aquarists keep their pH at 8.1 to 8.4. I keep mine around 7.82 to 7.94 mainly because I don't want to buffer it and throw the akalinity into a tizzy. The most important thing is that it be kept as stable as possible. It should not change more then .2 in a 24 hour period. A pH of 8.8 is way to to alkaline. I can't tell you how to lower it (make it more acidic) as I spend all the pH time trying to raise it in my tank.
If you find out why your pH is so high I would really like to know because it might give me some insight into raising mine other then the typical ways of doing it. Sorry I can't help with lowering it.