My wife always tests the FC before she starts her lessons and in the past if the FC started out at the minimum I would let her teach without bumping up the FC. Once the lessons started, I'm guessing that the FC would drop below the minimum every once in a while and algae would get ahead of the SWG. Now, if my pool's FC is below 7 ppm, CYA is 80, I have her bump up to 7 ppm with bleach and I haven't had a problem since. My pool is used differently than most residential pools so I have learned what I need to do to my pool to keep the algae from growing in it.
I have a feeling the OP's CYA measurement is off and if the FC is measured around 5 ppm often with the CYA at 80, the pool might be subject to develop algae if the FC drops below 5 during the day. The OP's pool might be on the edge a little too often and if they target a slightly higher FC and don't let it drop below 6 then I'm all for it.
I have a feeling the OP's CYA measurement is off and if the FC is measured around 5 ppm often with the CYA at 80, the pool might be subject to develop algae if the FC drops below 5 during the day. The OP's pool might be on the edge a little too often and if they target a slightly higher FC and don't let it drop below 6 then I'm all for it.