I hear ya. I had no control over reservoir temps outdoor, so I added pond-zyme with the water/nutrient mix. The roots stayed healthy and mostly white with minimal algae growth and no rot at all. It's not the end all be all, but it works and is super low maintenance...grew some great tomatoes with it too.
These were my Kratky girls, started in August I think, possibly early September. Basically 12/12 from seed outdoors. Nice, manageable plants.
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Decent looking roots, little bit of algae and discoloration from Mega Crop.
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