I posted previously about my brother in law who follows the traditional pool $tore methods. A few months ago he let me test his water with my Taylor kit and his CYA was 200+ (diluted test) and at that time his FC was a whopping 31 (brown on the OTO test). He will not drain his pool (his pool, his choice) but did back down on the pucks.
I recently retested his water for him and still got the CYA at 200+ but his FC was only 3. My question is, why doesn't he have algae? I thought that his minimum FC based on his high CYA would be in the neighborhood of 15. He does "shock" his pool every weekend with liquid chlorine from the pool $tore. Maybe that's just enough to keep the algae at bay?
Just trying to understand for my own knowledge.