Hey altaholic,

There is no reason to ph the solution, in fact when using Penertrator and Liguid light it is not reccomended to. When I use Folitec & Penertrator I don't adjust it either, but I use RO water that I check and it is ususally 6-6.1. If you know your ph runs very high or low, then adjust the water first then add the nutes.

In my personal grow where I use foliar, the light source is a hybred LED/T5 and it does not have the radiant energy of an HPS, so I do apply it when the lights are on. It'd be hard to apply in the dark, you would not be able to see what you're doing.

A friend I know uses Folitec/Penertrator with his 1000w HPS, he usually raises his lights, applies, then about an hour or two later lowers them.

BTW the reason that the PH is not critical, the plant is taking everything in thru it's leaf pores. It is when we are dealing with the grow medium and roots that it becomes an issue. Hydro likes lower ph like 5.5 while soil likes 6.3 or so.