Never used that stuff. Hang on google time.

Okay reading the blurb on a vendor's webiste, it acutally IS supposedly a stand-alone hydroponics fertilizer. GOOD.

Now your challenge is to bring your pH down into range. Try to lock it in at 6.0. Considering that you ARE using a correct fertilizer after all, your symptoms are pretty basic, simple, lockout from high pH.

You can still do a foliar feed using the stuff; just mix it at 1/4 what the bottle says and spray lightly. With the Mg def that advanced, if you have any Epsom salts, add a couple pinches to your spray bottle to correct. Don't put them in the res, since that's likely to interfere with your organic nutrient. You might also want to consider a live culture in your res to improve the plants' ability to use your compost tea, and help prevent unwanted microorganisms (fungus) attacking your roots.

The roots' being brown may have something to do with your compost tea. I don't know how much, or whether you have another problem. Is there an 'off' smell to them?

Next time you have an issue, the more information you give, including your fertilizer, the better.