1/5 - did a complete system clean, flushed res and refilled.
What a difference a few days make! Beneficial microbes were not working.. so I am going 'sterile' again. I was losing the battle against the brown algae - it was time for some drastic measures.
I TOTALLY cleaned out the system. Drained, flushed the buckets, flushed again, and again with a strong h2o2 solution running through the pipes! Then, wiped it all down with strong h2o2. Found lots of SHIT (bacterial clumps of growth) coming out of my piping. Took FOREVER.. but the system is nearly surgical clean again. Refilled with Clear Rez and ran the system.
I took out each plant and removed any dead roots, cleaned up what was left, flushed minimal roots with some h2o2 water.
One day later... new roots are popping out everywhere, plants appear to be back on the road to recovery.. new growth, plants are straightening out. Glad I kept with it, this grow has been challenging, but I've learned a ton.
I've been trying to guesstimate the oxidizing level in the RES. I bought some pool test-strips to measure total and free chlorine. A part of science I never knew about and have not heard mentioned on the forums. Basically, you want a specific amount of free chlorine in the system as a sterilizer... but if you have bacteria - your levels are constantly being absorbed / used. The 'minimal level' is unknowable without a way to measure. The first test-strips I got are not accurate enough, so I found some better ones on amazon that are EPA certified for drinking water and will measure (so they claim) down to .01ppm. Perfect, will update when I get them and try - this should allow me to control the sanitizer (Clear Rez) like any other aspect of the grow.
Will update with some photos in the near future... things are looking pretty good.