I've posted elsewhere that my pool was installed this year with a Nature2 system. I followed the instructions and had FC around 0.5 -1.0 (recommended with N2) and I had algae and cloudy water on and off until I found BBB.
I assumed that my problem was to much CYA caused by the trichlor tabs. Now I suspect another partial suspect...
The Nature2 system is installed with a "Startup" cartridge. This thing is supposed to be removed after 7 days and replaced with a mineral cartridge. Well guess what? My PB never changed it, and I never realized until now.
So basically I ran my pool from March to August at 1ppm FC. No bug surprise that I had to shock all the time. The shock was powder trichlor - so it was loaded with CYA - and each time my CYA got higher and higher. A vicious cycle that ended in mustard algae.
So, I am not defending Nature2, but I don't think that in my case it had a fair chance as it was improperly installed.
I will be called my PB in the morning. Someone owes me an apology and also some $$$ for all the shock and chems that I have bought.
The good news is that after a week of BBB my pool's chemistry is perfect and crystal clear.