Iron in my well water is a problem for me too. I have two wells both with similar iron/manganese content. One well we use for our drinking water and we have a ozone treatment system which precipitates out the iron/manganese into a filter which requires periodic cleaning. This also requires a large storage tank 2500 gallon for us. Does a good job but costs starting at $5000. Our other well we use for landscape/greenhouse water, and has a MacClean back washing Iron filter. This removes a lot of the iron but still requires water nozzles to be cleaned regularly. This system costs about $600. Al

We have iron in our water and it stained my pool and so I have to use a metal treatment in the pool water. Maybe you could get a bottle of it to treat the water you use for your plants.