after reading this discussion, I am still a little confused. We are setting up 2 5x40 gravel grow beds (gravel not in beds yet) and have tested our well water and it is 7.5 give or take. I washed and tested the gravel we are going to use with vinegar and there is no fizzing. I then washed and retested water with the gravel in it and ph indicated it was still around 7.5- 7.8 . I let it sit for 3 days with the gravel in it and now it is 9.7. Should I get different gravel ??
thanks randall......that is good to know and yes it is crushed granite best I can tell and that is mainly what is available to us in southern cal.
Randall Wimbish said:
Once your system has cycled the bacteria will constantly be pushing your PH lower. Personally, I think I would go with what you have. You can always lower the PH with acid. Muriatic acid from a pool supply is very cheap and a little goes a long way. One of my systems is crushed granite and the PH is a little high but it is the most maintenance free of my three systems. The other two systems that have PH nuteral media always keep me busy adding things lo raise the PH..