@Figgy;
We draw our water from a aquifer and it's hard as hell (830ppm) most of the white residue is prob. lime.
That's our trouble, I have to chuck my root pouches after 3 grows because the walls are rock hard with lime.
If your water source comes from limestone cal def could easily be the prob.
Check your runoff ph.

We draw our water from a aquifer and it's hard as hell (830ppm) most of the white residue is prob. lime.
That's our trouble, I have to chuck my root pouches after 3 grows because the walls are rock hard with lime.
If your water source comes from limestone cal def could easily be the prob.
Check your runoff ph.
