If you're ever thinking about exchanging the water, that's a good time to do an ascorbic acid treatment to the pool. You may find you can remove enough iron by just focusing on the plastic which really attracts it (weir door, skimmer basket, intake and return fittings, pump basket (if you see any of those turning brown)). You can use the vitamin C bucket method to remove the iron, whiten everything up, and discard the water in the bucket. Each time they stain, followed by removal, takes out a wee bit of iron.
You'll read on the sequestrant bottle that the iron will be trapped in the filter after sequestration. IMO, that's manufacturer/marketing over-stating reality, but I suspect you will trap some. The cartridges can also be rinsed to get rid of some iron.
If it gets much worse, consider the whole pool ascorbic acid/sequester/drain/replace method. How much $ was your delivered water? For now, it's kinda good to see it in an obvious and easy to treat place. It's now your canary in the coal mine for iron.