Yesterday the pool was a little cloudy with some stains on the vertical part of the wall at the deep end. This really looked like dirt that the iron had collected onto. I brushed the wall. I got in the pool last evening and these areas looked green like algae. I dumped enough chlorine to get me to 3 ppm or so. I didn't have a computer handy for the calculator and guessed. This morning it was holding at 3.5 ppm and looked a little better. I was at home about 1:30, FC was 3.0 and it looked very clear. I've been holding off vaccuming until I got my flagstone finished because of all the sand, but think Friday will be the day to vaccum and hopefully be fully done with this mess.
I do have two questions.
1. If the iron wasn't in the city water, then where could it have come from? When I opened the pool in March 08, I was coming off the first winter with the pool. My house had just bee completed with us moving in 10/07. When I took the cover off I found a few roofing nails in the bottom of the pool and a few rust stains on the bottom. No staining occured anywhere else. When I took the cover off this spring (trampoline type that lets dirt through but not leaves) there was lots of Alabama red clay on the steps. Iron gives the clay it's color.....so, I guess the iron in the clay did this. Does this sound plausible? Does this sound likely? I am downwind from Birmingham, AL and B'ham has awful air quality. Maybe rain was the source. Anyone heard of either of these providing enough iron to stain a pool?
2. Is there any practical way to test your iron content and what is the level that staining becomes a problem? Seems like if I ever had to replace my water then this would be something to consider. Salt is the big expense of replacing the pool water, but if I burn through $25 of sequestrant every 3 weeks, year round, then at some point it becomes cheaper to just replace the water and be done with it. The little engineer in me just knows that I'll have that break even point calculated in the very near future.
Thanks for everyone's help and patience. Things like this are what make this site so wonderful.
I do have two questions.
1. If the iron wasn't in the city water, then where could it have come from? When I opened the pool in March 08, I was coming off the first winter with the pool. My house had just bee completed with us moving in 10/07. When I took the cover off I found a few roofing nails in the bottom of the pool and a few rust stains on the bottom. No staining occured anywhere else. When I took the cover off this spring (trampoline type that lets dirt through but not leaves) there was lots of Alabama red clay on the steps. Iron gives the clay it's color.....so, I guess the iron in the clay did this. Does this sound plausible? Does this sound likely? I am downwind from Birmingham, AL and B'ham has awful air quality. Maybe rain was the source. Anyone heard of either of these providing enough iron to stain a pool?
2. Is there any practical way to test your iron content and what is the level that staining becomes a problem? Seems like if I ever had to replace my water then this would be something to consider. Salt is the big expense of replacing the pool water, but if I burn through $25 of sequestrant every 3 weeks, year round, then at some point it becomes cheaper to just replace the water and be done with it. The little engineer in me just knows that I'll have that break even point calculated in the very near future.
Thanks for everyone's help and patience. Things like this are what make this site so wonderful.
Plus this has been the siltiest year we've ever had in the 23 years we've been here. We are a few feet lower than many of the houses on our hill so we get lots of runoff with loads of silt and sand. We've always had some dogs who do a little swimming but these three are constantly in and out of the pool. I've estimated I vac up about 1 lb of silt a day, not counting what makes it to the filter, (measure damp and not dripping wet) and this is the first year I've had any significant staining that is metal instead of organic. I was on Ionization for years, until 2 months ago when I switched to BBB. I've, also, replaced over half of the water in pool in past month but we don't have measurable iron in our tap water. Currently in the middle of AA treatment. Some of the iron stains are still present so picking up some more AA at the local Vit Shoppe today. I've already put in 6 lbs. ordered from Amazon and about 1/3rd the price I'll pay today. Should have ordered more in the beginning. 
BTW..... I did add Polyquat 60 first so likely won't have any algae and the water is in the lower 60's temp so less chance of algae bloom but longer time for AA treatment to work.