First of all, mods, please move this if it would be better suited elsewhere.
Second, I just had half of this typed and the power went out, so now I get to start over.
Okay, now the topic above got me thinking...and wondering...and making a long drawn out post to ask some questions.
We are on well water out here, and not surprisingly, we have metals in our water. Specifically, ferrous iron. Depending on the time of year, it can be low (1-1.5ppm) to extreme (5ppm, verified by multiple locations) and a major pain in the ***. The last time we had a pool was around 3 years ago, and between the metals and complete lack of time to take care of it, we took it down. It was an Intex metal frame, so it was just easier to take down than have it become a giant mosquito nest.
Anyways, I followed the advice at PoolForum (fill pool, add sequestrant and Poly60, wait about a week, then gradually raise CL). Within 5 minutes of adding even a small amount of bleach, BAM! Dark, dark brown pool tea. I tried the whole sequence over and over, adding more and more sequestrant each time, no change. After 3 or 4 times of doing that, I was ready to drain the thing and set it on fire. We tried different products, HTH Metal Control, Sequa-Sol, and Metal Free. I don't know if the HTH is less concentrated (after all, it is cheaper than all the others out there!) but that was the only one we could buy regularly. The Metal Free was a joke, at something like $35/bottle, and I couldn't get anything else except for online.
Now for some questions. The HTH says on the bottle not to add more than 1 quart/10,000 gallons for 1 ppm metals. Is that because using more could precipitate calcium out of the water? That Intex was only a little more than 5,000 gallons IIRC, and the last couple drain and refills I was using 6-7 bottles just for a startup dose. Seems a little excessive to me, but I'm not a chemist nor a pool expert. Or is it maybe that the HTH is just too weak for what I need it to do?
Our well water consistently has (and did even back then) a pH of 7.0-7.2, and I would always start out with 6-8 oz. of bleach, which according the the pool calculator would keep my CL well below 1, so I've always been stumped about getting brown water that quickly.
The only thing that worked was something bk406 talked about in topic above, except I did it on purpose. I shocked the pool to at least 20ppm, but in my situation the filter was WAY overmatched. Since the filter couldn't handle it, I did something that is generally not recommended here, but in that case it was necessary - I flocced the living **** out of that pool. I let it circulate the whole day, then shut the pump off that evening and let it settle. The next day, CLEAR water! Except the inch thick mass of clumped iron on the bottom. I vac'd to waste (if you need to know how to do that on an Intex, ask me, it's really easy), lost probably 6" of water in the process, but had beautiful, sparkly water!
I refilled the pool with softened water, and everything was great the rest of the season. My water softener is at least 20 years old, and is a Culligan Mark 45. After talking with Culligan back then, I was able to determine my softener had the capacity to produce around 1,500 gallons per recharge with my CH and average 3ppm iron. That's at 8 lbs. per recharge.
So, more questions. When I get my AGP set up, would it be better to go the 'bk406 method', the floc and vac, or dump a whole bunch of bottles of HTH in there? Or maybe even suggest a brand that would work better? If I have to, I'll try to get 55 gallon drums of HTH! Has anyone here even dealt with iron content as high as 5ppm? Maybe with a content that high, a sequestrant won't work? Given recharge times for the softener, it would take days to fill up completely with softened water!
Wow, didn't expect this post to be this long. I'm just trying to be as prepared as possible when we fill this pool up soon, and dealing with metals in the water can be confusing to a lot of people, myself included! I understand why you get discoloration and staining, and how to generally take care of it, but I just haven't seen a situation like this on here or PF before!
Okay, end book. Umm, I mean post.