Hi Ed, and welcome.
I have a bit more iron than you, and have battled the well since rehabbing this foreclosure a few years ago.
Here are some options if you don't truck in metal free water - note that these might ameliorate staining and reduce the iron load going into your pool, but will not necessarily AVoid/prevent some iron from getting in!
1. Try this...it seems to work reasonably well on my hot tub, which in winter, gets raw well water:
Amazon.com : Pre Fresh Garden Hose End Water Filter all purpose, pool, spa, hot tub, pets, car wash : Garden Hose Parts : Patio, Lawn Garden. It has enough capacity for your fill and a few more top ups, but keep track as capacity is 8k gallons.
2. IME, Jacks pink or metal magic work best on iron -- apply immediately on adding water to sequester any iron getting in, and maintain. Metal MAgic may be more convenient for you with SWG in that its application reqs are to add with ph above 7.5, whereas Jack's requires first lowering ph to 7.2.
3. Since you're SWG, watch that ph...high ph causes staining with metals...if you're able to keep it at 7.2-7.4 ish, all the better
4. If you have a large capacity water softener, preferably dual tank to avoid regeneration/tapping out the water...you may wish to consider plumbing one of your outdoor faucets to it. That way you'd be adding mildly saline water...little iron gets through and you'd need less salt to account fr topping up/dilution. My soft water tap is about 450 ppm salt based on my hardness...everyone's is different depending on how many grains of hardness you have.
The 2 cons of this approach is that with plaster, you may need to ADD CH to keep your balance, and that the softened faucet will not be useful for plants/irrigation over time...eg a bit won't hurt, but in a dry spell, lawn and plantings can flag from salt build up. Which is why outdoor faucets usually bypass softener on construction
Also note that some of the "physical" filtering tricks like putting stuff in the skimmer noted in above post usually are used when an iron load has oxidized from shock level chlorine, which oxidizes the iron into visible water tint. Won't do much while iron is in suspension
Avoid high, shock levels of chlorine until at least a week after using sequestrant...preferably EVER
. ...Which is possible using TFP testing and sanitizing approaches.
In that regard if you haven't already, be sure you're not flying blind on your testing by getting a TFT100 or Taylor 2006k at
http://www.tfttestkits.net if you haven't already, and be sure to read up in pool school (see links in my signature.)
Hope that helps!