Dropping PH

[urbanfarmer]

i have 100gal gb, first time i added a dozen egg shells dried and crushed, and a dozen clam shells i smashed up.. ph went from 6.4 up to high 6's and stayed there.. i added another dozen clam shells after a month or two.. ph has been sitting in the low 7's, usually 7.2
that's with 150gal ft, 45 yellow perch, a few dozen rosy reds, and a couple dozen crayfish

Good to know. Thank you