Good morning, Chris.
I don't have a birm filter because I have some maganese in my water, plus a bit of sulphur, and my well is more than 50' deep, meaning I'd have to oxygenate the water for it to work right. Those are a few aspects you should check, just so you know, that Ive been told interfere with its performance.
But I did want to elaborate a bit more on treated water strategy when you have a pool so that you have the best chance of success if you do decide to change over
I also wonder a bit about this water staining concrete from overspray if the iron reading is truly .3 -- my well has 2 ppm iron and will stain, but my treated water at about .33 does not in brief exposures. The difference might be your high ph as mine is low (6.9 - 7.0 ish).
At any rate, when I first moved here after debating an iron curtain system, my water guy convinced me a single softener would be adequate.
He meant to be helpful but he didn't anticipate how I would actually use the water with the pool. In summer, I used to dislike using a cover, which means I'm inclined to top up be a couple of inches a week if there's little rain,etc. Its normal to lose a quarter inch a day to evaporation, especially if you keep your pool at 90 as I do.
So, the softener takes my iron from 2 down to about .5 ppm. At that rate, even though my outdoor pool spigot is plumbed to the softener (which is not normal...btw) I still struggled a lot with increasing concentrations of iron, and the heavy loads of sequestrant to manage it.
Nowadays, I also run a reducing 25 micron to 1 micron Pentek 10" filter off the outdoor spigot, which at the moment gets it down to .33.
But with the single softener, what would happen in early days is I'd be filling the pool and not realizing the softener had tapped out. It took a while til I figured out this was happening.
Once I did, I had a dual tank system installed so that one could always be regenerating. This also reduced bed fouling from the iron, and decreased events where raw well water got into the pool, though that can happen with bridging as well.
SO, if all your other conditions are met for optimal birm filter use, consider a dual setup so that you're not caught short during regeneration or while the tank is tapped out. It will make a big difference in the rate/speed of your iron accumulation -- assuming that like most filters, you will reduce but not eliminate completely all iron.
I will say, though, that if I had to choose between a well with ANY iron in it and a potable municipal supply without iron in it, I'd choose the latter for the pool
.3 ppm, if accurate, is reasonably low but high enough to stain in a pool environment once its accumulated to an in-pool read of .3 ppm, which inevitably it may one day. It is especially likely to stain if you don't control your ph to the 7.2-7.4 range, which can be difficult.
Then, for the next span of years, you could be spending your money on HEDP sequestrant and possibly stain treatments (instead of the municipal water), which can easily cost a good few to several hundred a year...the costs will escalate as the iron accumulates. Your annual rainfall averages will help this to some degree, but since you don't backwash with a cartridge filter, your odds of dilution from rainwater will slow down the accumulation but will not act like exchange.
I guess long-term, I'd be a bit reluctant to gve up your access to municipal water. If you started with the birm filter just for the pool but kept your house water plumbed, you'd have somewhere to go if you found the rate of accumulation unacceptable. If the filter actually got the iron to zero, and this proved reliable for a few years, then I might plumb it to the house. I would just hate to see you trapped into water-change-by-truckload, which is not cheap in my neck of the woods ($1,000).
So, my comment might sound like I'm recommending against your move -- I'm not exactly...I'm just trying to give you an idea of where the snags may be in the long term so that you consider all angles. Metal management in a pool is a pita!
that was....
