Problems with new system

[Bill Tyson]

I have a 100 gal fish tank and 2 50 gal grow beds with bell syphons. Grow media is lava rock on the bottom and hydroton. I started 6 weeks ago and went with the fishless cycling. At first my ammonia was zero and PH about 7.6. I planted the beds and the plants are doing fine. My new water readings are ammonia higher than 8 PH lower than 6 nitrites and nitrates both are zero.  I am afraid of added fish with the ammonia levels so high. I am not sure what I did wrong..