When we purchased this house last October, the pool was in pretty rough shape. Once getting the numbers where they needed to be, I wanted to start focusing on removing the stains. The walls have 2 "rings", one at the current water level and one where the previous owners let the pool evaporate to nearly only 2 feet of water left. Then, in between the 2 rings, there is a reddish brown stain on all the walls. The bottoms and steps are fine. I held a chlorine puck to the side for a minute or so but it made no difference. I do not have vitamin c tablets to do the other test, but I am assuming the stain could be metallic? We have very hard water here in this part of Ohio. I have scrubbed and scrubbed with different things such as a brush and also with magic eraser, it will not touch these stains. I bought some HTH Metal Control and would like to try it. Does iron sound like the reasons for these stains? I just finished testing the water and also noticed my TA is high, 190, is this dangerous to swim?
pH - 7.5
TC - a little above 5
TC - 8.5 (FC 8.5/CC 0)
CH - 175
TA - 190
CYA - 60
So, question 1 is from the above with the reddish brown stains.
2.) High alkalinity issue and safety of swimming
3.) I have 1 skimmer and 2 main drains, both on the same side of the rectangle pool. It seems to be doing a good job with the top floating stuff but It does not appear that the finer particles are not being sucked in. At night time with the pool light on you can see these particles floating/suspended in mid depth water. and if I turn the pumps off for a few hours, this stuff settles to the bottom. Isn't this type of stuff supposed to be sucked in by the main drains?
4.) Are there any "plugs" used in the closing process for the main drains? The 2 main drains each have a solid white plastic "X" in the middle of them. Not sure if that is part of the main drain housing or if that is a plug that should have been removed when we opened the pool?
5.) Clarifier and also Metal Control, how soon can we swim after these products, it doesn't state on the bottle.
I apologize in advance for the newbie questions, but appreciate your help.