First post here, but I've looked over alot of the posts and can't find anything exactly like my problem so here goes
I have brown stains on the PVC skimmer housing/baskets (see attached image) , filter basket and inside fitting in the pool, to a lesser degree the pvc on the polaris fittings and the bottom of the polaris 360 (the white part) Interestingly this does not seem to affect the spa fittings (spa overflowing into pool so 80% of return water goes to spa first)
The pool is now 2 seasons old, I originally did add some algae agent (as I was instructed) but never really kept up with that, Also have the Nature 2 installed but only changed the cartridge twice since having the pool and I just removed it barely had any material left in it. I do have a heater. temp kept at 84
Have not gotten any formal tests for copper or iron but did take one of the fittings off and put it in a cup and crushed up some Vit C tabs and it nicely removed the stain, the next eyeball fitting I tried didn't come clean but being resourceful I looked around the house and found some Bar Keepers Friend mixed up in a cup and presto the stains came off (looking at the label it says it contains oxalic acid) as well, removing the skimmer baskets it was easy to clean the brown stains with this agent so I'm reasonably convinced from what I'm reading here it's likely iron staining.
My issue is this only seems to be affecting the PVC and not the pool walls which are pristine (it's Caribbean pebbletec so granted it might be hard to judge if there was a light layer covering everywhere but certainly no blotches anywhere . Never had algae, water has always been clear, live in NC and we use the spa in winter so I never shut the pool down just reduce filter times in winter
Now the questions
1. So should I just clean these areas locally or would an AA or oxalic acid treatment be warranted for the whole pool?
2. should I routinely be adding a sequestrate to prevent them from coming back?
3. Now that I'm not planning on using the Nature2 is there something I need to add to prevent any copper that was introduced by this system from causing problems?
4. Can I use something like Jacks Ionizer stuff instead of AA
For interest sake can anyone explain why I don't get these stains at all on the spa fittings
the circuit is pump-> filter-> Nature2 -> Heater -> split returns to spa and pool with the pool also having the Venturi and inline chlorinator
if it was the Nature2 I would expect it to affect both areas
Only the chlorinator and the ozone only go to the pool, but if it was the ozone why is it affecting the return baskets since the ozone should be well gone by then?
(FYI in past had been using trichlor until I found this site , CYA was off charts after half drain and refill it's 70, now using Cal-hypo until my CH gets up and then will use bleach, with trichlor in the chlorinator for vacation times
FC 5.5 (in the PM) targeting 8
Using 2000K kit