I did a few searches of the forum regarding the potential effect of HTH Metal Control on pool chemistry and didn't really find anything.
I'll be needing to add some water to pool later this week (evaporation, kids splashing, and soon a backwash), and I'll be using well water that is from a source that is tapped off my main water line prior to the water softener system for the house. When I did my initial set-up and fill, I used about 750 gallons of well water then had a pool water co. fill it the rest of the way. When I did my initial chlorine addition, I got tea-brown water in the filter and some minor staining. That went away with some light brushing. My theory is that the chlorine and the iron from my initial 750 gal fill reacted. I haven't used a metal control product yet as I haven't seen the need to (no more staining, etc.), but don't want to risk it with my topping-off. I looked at the metaltrap filter and it seems pricey and not big enough to do an adequate job at any decent flow-rate. So, I picked up a bottle of HTH metal control after seeing it had the same active ingredients as Magic Jack. But, my question is this:
What is the potential impact to my pool's chemistry (change in pH, TA, CH, etc.), if any? Here are my test results from this PM:
CC: 0.5 or less
CYA: 60 (still working itself into the water)
Borates: Not Tested Yet - test strips on the way
Iron: Not Tested Yet - kit on the way.
Note: I'm letting the FC drift down from shock levels earlier in the week as I got my CYA in the pool and started to get it distributed into the water. I'll kick on the SWG tomorrow evening, as the FC has dropped about 2.5 to 3 ppm per day the last two, as the CYA kicked in (sunny, 89F on Sunday, 93F today, high 80's tomorrow).
Or should I try the Metaltrap Liquid?