FC levels

[David 9512]

My pool cleaner says 4 FC level is Max, but the cya/chlorine recommends 5-7 with a cya of 40.
PH 7.5
TA 70
CYA 40
FC 4
CC 4.5
CH 250
What's your thoughts on the recommended FC level as compared to the pool cleaner max of 4. It is a Dolphin M500.
Thanks

 

[Donldson]

Lots of pool equipment says things like that, and it would be accurate if there were no CYA in the water. However because of the buffering effects of CYA the target FC levels are actually far less harsh on equipment (and swimmers) than even 1 ppm FC in a pool with no CYA. Even SLAM level is less harsh than 4 ppm FC / 0 CYA. The industry is starting to come around on this relationship, but it will be a long time before tables and warnings change if they ever do.

I'm sure plenty of people will chime in with their experiences in this matter (your cleaner isn't the only one with that warning) but let me be the first to say you can disregard this particular warning.

 

[mknauss]

Their max FC is at 0 CYA. At the recommended FC for your CYA the equivalent active chlorine is a fraction of that with 0 CYA.

 

[mknauss]

My Active20 Dolphin robot lives in 6+ FC. CYA of 70 ppm.