My biggest concern since posting is brown slime on the submerged roots. I did my best to light-proof my buckets but perhaps some pin holes have shown up. Thanks hvg!

EDIT: it appears that Subculture B contains some fungi as well as bacteria.

Slime is no good. That's bacteria if it's the slime one usually gets in a hydroponic system. Some pinholes shouldn't really matter. I have light leaks through the hydroton at the very top of some bucket net pot lids since the run the mesh up really far sometimes. Causes no issues.

I have had a slime issue before and the best solution I found was using beneficial microbes. I've read horror stories on some of the weed forums about people battling slime for 6 months. Adding water chillers, more air, hydrogen peroxide, bleach, etc. What worked for some didn't for others. But what always seems to work is beneficials. Before people started using those bleach, or some form oxidizer, seemed to be the protocol to keep a sterile system but miss one dose or run it too low and you're screwed. Slime can accumulate very fast and bleach can oxidize out of your system very quickly. I've used bleach before and it worked but it's a lot of maintenance. Besides, using beneficial microbes adds an enormous amount of other benefits to your plants basically creating soil-like flora in water.

Anyway, I ramble. Just try to get your hands on some beneficial microbe product. You should clean and sterilize everything and then start with fresh solution and the beneficials. That should take care of it. Just make sure you're getting good air flow into the buckets, microbes need oxygen too.

Stick with it. Most growers I know have all had algae or slime or root rot issues before. Part of the learning curve.

Thanks for your advise and encouragement hvg. I appreciate it. If that is what you call rambling then keep it coming :-)

Your right, it contains some trichoderma. I don't remember that being in there but if it was when I used it I didn't notice the issues I had with other fungi containing products. Roots Organics OregonismXL and the Fox Farm Microbe Brew I remember causing sediment issues and build up on my air stones. And the Fox Farm didn't smell that good. I just checked and they both have a lot of fungi. Any product that was solely bacteria that I have used stayed super clean. There has been a couple besides hydroguard but I can't remember off the top of my head. The hydro shop guys give me samples all the time and I test them and let them know what I think.

That is weird though. I always thought subculture B (bacillus) was the bacteria and subculture M was the fungi. Never used M. The subculture B if I remember correctly was on the pricey side considering it's dilution rate. One of the other reasons I used Hydroguard. 2ml per gallon and since I don't do water changes I use 1 ml per gallon weekly as a maintenance dose. Quart bottle lasts me 6 months.

Don't shy away from fungi containing products just based on my thoughts. As I've said, I am a stickler for clean buckets. It may not bother you. Or even use it at a half dose. Any of that stuff multiplies very quickly.

I have great news for you! There is an alternative product, and it's literally one MILLION times more concentrated than Hydroguard. It's called Southern AG Garden Friendly Fungicide (you can find it on Amazon), and an 8 fluid oz bottle runs 9 bucks. Now, it has 1 billion CFU's per mL, while Hydroguard has a miserly 1 thousand CFU's per mL, so it's one million times more concentrated. I used 1 part Fungicide and 19 parts RO water, and then use 1-3 mL per gallon, and I haven't had any problems with root rot or algae growth in my res. Hope this helps!

Thanks Ethan.

I appreciate the suggestion though I doubt it's available in my part of the world.