Hi, I've been using Fox farms for about a year now. I use about the same mixes in a hydroponic system and find the pH is around 6.8 when mixed with my tap water. You can get a basic 'drops' method pH test kit for next to nothing. Knowing your pH is important as you probably well know. Nutrient up take is greatly affected by changes in pH sometimes resulting in nutrient lock out, which manifests as various patterns of yellowing on the leaves. A nutrient mixes' pH can change quickly in relation to a lot of things like... how many plants are being fed, how big they are, reservoir volume & temp and actual nutrients added and how long you go between topping off the reservoir and totally changing it. etc. (*NOTE* changing nutes once a week is pretty bomb proof, you still will probably need to top off though, use fresh water not nute mix to top off.)sorry if this covers old ground for you.
Some time when you can afford it you ought to look into a digital pH pen & a TDS or EC meter too. Good to have a clear picture of what your plant is sucking up. Test every other day if you can, then you'll see the pattern that develops, as well as the weak spots in your nutrient cycle. i.e. pH drops 2 points every 3 days...meaning you need to add pH 'UP' to counteract the pH drop, which in turn maintains proper nute up take by the plants...
Though I like the results I get with Fox Farms' stuff they aren't totally organic. I plan to switch to Earth juice for the 'All organic' grow. Hope this helps, Happy Gardening! GrowIT!
