He had posted a different thread showing his roots, they weren't brown, just nutrient stained. Based off of those pics of your roots in the different thread you had posted, you didn't have root rot. Looks to me like combined stress of possible bug issues, and a not so uncommon issue with calcium. If I feed too heavy with P boosters, it seems to have an affect on my plant's calcium and/or mag uptake, and especially if I'm using any type of LED lighting. I'd recommend to keep using the hydroguard, or better yet (and cheaper), Great White, even if temps are in line, it always made my roots grow faster and more robust. A million things can throw calcium out of whack, and this is why you see so many calcium deficient plants, even though half the time the calcium is there, but simply not available to the roots. I don't think you're in a pickle at all, there are just a few factors you are still needing to get in line, that's all.