You really should fill out the trouble shooting form. What is "ph water"? Do you mean Reverse Osmosis? RO does remove all minerals and you might be causing a deficiency of mag, I know I did and it looked similar. But if you mean ph stabilized regular water, then there is a different issue, not a mag def, which the plants really do not need a lot of.

So, fill out the form so the smart dudes can help ya more than I!