Once cycled, PH should begin to drop. I wouldn't do anything.
You can add seaweed extract to a new system for nutrients.
You have a very High PH. This prevents the plants to absorb correctly the nutrients, mainly the metals and in particular manganese and Iron. As a matter of fact above 7.5 the only veggie in theory possible is the asparagus.
You may expect chlorosis on your plants and should add Iron in the form of chelate.
I do not know of a practical manner to lower it in aquaponics. Buffering it up to 6.8 with crushed calcium carbonate (7.2) is easy when your water is neutral (7.0).
Furthermore do not expect a good harvest the first time as your system isn't mature. Californians worms are of great help.
pH is way to high. the chart below shows what nutrients are best absorbed in what pH. It's been a while since this was posted but tonight I'm bored and going through the forums seeing if I can add anything to these discussions. If ammonia is dropping but nitrites are high (your numbers were) and nitrates are low (your numbers were) then your system is not fully cycled yet. But at that time you dont have anywhere near enough nutrients built up to grow anything.
Thanks for the advise! It's been awhile since I've posted.
My pH has dropped to about 7.2, the tank has cycled - 0.0 ammonia 0.0 nitrites ~40ppm Nitrate.
I get that the system is still immature. I guess only time will take care of that. However, I will tell you that
every bloom on pepper, squash, tomato, etc. has shriveled and died on the stem. No flowering fruit!
I think its a germination problem, as the system is indoor! any thoughts!