Why wouldn't I believe the manufacture of the product instead of strangers on the internet? No offense, this site is amazing and I know many here are WAY more experienced than myself, but I am always weary of any advice from "internet experts" especially when it causes no harm to follow the manufactures rules. It is had to tell on a site like this who has what experience. If you ask 10 people on the internet a pool question you will probably get 2 or more different answers unless communal reinforcement is in play, which is very possible on a forum like this. I know some people may not even read their manuals but I am a rule follower I guess. hehe
Understood, but I think you missed my point that I was joking around with.
If you follow the chemistry recommendations found in most pool manuals or from the pool store recommendations, you are bound to get a green pool since they ignore the FC/CYA relationship which is fundamental to the science-based teaching here. So, if we
know that they are wrong with that information, why believe other parts of the information they provide? Granted, there is no harm to turning off the SWG when adding chemicals besides the hassle.
Thing is, the writers of the manual do not know how we recommend adding chemicals. If you are pouring chemicals into your skimmer with the pump running ... dang right you should probably turn the SWG off, although you are likely causing damage either way. If you are adding chemicals into the pool in a return jet maybe on the opposite end of the skimmer (like we recommend), then it will be so well mixed in the water before being pulling into the equipment, that it just is not worth the effort to turn the SWG off.
Anther SWG manufacturer recommendation: put a check valve after a heater before the SWG. There is just no point to this and it is likely a hold over from a tablet feeder installation which DEFINITELY should have a check valve there.
Basically, if you are following the TFP chemistry recommendations, you are likely violating the SWG pool level recommendations already. And having to play with the SWG settings every time you add a chemical is just no trouble free IMO. But, again, you are right, there is not harm in doing so