"The brick" is from underwatering. The entire rootball needs some moisture and air to survive. When you let the medium completely dry out, it will need either a good soaking or a surfactant.

I slowly add the properly ph'd water. I add a cup, wait a minute. Add a cup, wait a minute. Add a cup.....on and on till the rootball becomes pliable again.
Or
You can use a surfactant. A surfactant lessens surface tension of the water, allowing for easier absorption into the medium. 1/4 tsp of dishsoap per gallon of water usually does the trick, but never use anti-bacterial soaps. (or it'll kill the beneficial bacteria) One or two applications should be fine, and don't make dishsoap a regular weekly additive.

Any color coded test will be skewed by the tinting. You likely aren't even in the ballpark of an accurate runoff number. Most likely it's at neutral or slightly lower. (6.7-7.0ish) MG is pre-buffered, and the buffering lasts about 6-8 weeks or so.

If the bag doesn't specifically say it's the 6 month formula, then it's the regular 3 month mix, which should be fine...if properly watered. I believe I was adding nutrients to my MG soil at about 4-6 weeks. Half doses at first, and watch for the plants reaction.