PH level of new system

[Bill Tyson]

I started the cycling 6 weeks ago for my 100gal aquaponics system. Things were going well at first with the ammonia level dropping to 0, but the PH went down to 6 or lower. I then added crushed coral that was filtered through a bag and the ammonia level spiked to 8 or above the PH didn't change. I had read that coral will raise the PH. What went wrong?

[Alex Veidel]

How long have you had the coral in there?

[Bill Tyson]

I left 2 cups of coral in a bag for 2 weeks. I have now removed it and replaced 50% of the water with rainwater. Have not tested again for ammonia or PH, but will do so soon.