Well water -- Can you pre-filter out iron in solution when filling the pool?

[snowypool]

Hi, I've been studying the information on this site since last year (our first season of having a pool), and it has been invaluable. I have tried to read everything I could find on filling pools with well water and the various methods to deal with the iron issue.

Last year, we filled the pool, and immediately upon adding the startup chemicals the water turned from crystal clear to green. We bought some Metal Magic, and after a couple days the issue was resolved. Every few weeks we'd notice the pool beginning to turn green again, would add more metal magic, and it would resolve to clear.

This never ending cycle doesn't feel like the ideal solution, and this year, as we are about to fill the pool (we are not getting water delivered due to cost constraints in our area, especially as our pool is seasonal), I would love to pre-filter the water from the hose as we are filling, to avoid or at least minimize the iron issue.

I've tried to read as much as I could in the many prior threads about this, and have read about some of the various methods ('slime bag', bucket with polyfill, pre-filter hose attachment, etc.

There is one thing I'm still unclear on though: Can we pre-filter iron out of the water when the iron is not visible (i.e. is presumably in solution?) I keep reading here that the best time to filter is when it's green/brown/visible/out of solution. Our water comes out of the well crystal clear. Is it still possible in this case to pre-filter iron out as we are filling the pool? And if so, what would be the best of the various methods?

Thanks for any help and insight!

 

[mknauss]

Welcome to the forum.
Read Iron Fill Water Filter - Further Reading

 

[JoyfulNoise]

The trick to taking dissolved iron (Fe2+) out of water is to oxidize to the insoluble form (Fe3+) and then mechanically filter it. That is how whole house iron filters work. You could try the bucket filter method where you add some calcium hypochlorite tablets (NST tablets) to the bucket and then use the high pH and chlorine created by the tablets to precipitate the iron before it gets to your pool. That would typically require another bucket with poly fill to capture the iron. Then the mechanically filtered water can be added to the pool. The slower the fill process the better as a poly fill bucket filter is very slow at capturing precipitated iron.

It has to be cal-hypo tablets, not trichlor. You need high pH and high FC to make iron precipitate and trichlor is acidic.

 

[Newdude]

Another Islander going through similar at the moment found Pentek filters that worked down to 0.5 microns which should work for you. They haven't been put in service yet so no results to report.