Iron Filtering with Sequestrant

[poologant]

Ok, first post, so be patient

So, I have iron staining in my pool. Pretty sure it came from using Clorox Fast Dissolving pool salt though I'm not prepared to declare it definitively.

I have the stains mostly lifted with AA and presently have Jacks Purple Stuff as the sequestrant. While this is ok for the moment, I want to remove the iron long term. I also understand the most effective way to replace the water with iron-free water. However, I have an IronEater Air-Injection Fleck 5600-SXT filter with carbon media. I'd like to remove it with the filter. I've setup and tested the general layout as such:

Submersible Pump -> Hose into Filter -> Hose out of Filter back to pool / Backwash line exiting to waste drain (not back in pool)

I spoke with the filter company tech support and they said it should work so long as I do the following:

• Limit the GPM to 3, slower is better (I was at 5gpm)
• Manually close the line back to the pool during backwashing (I was)
• Backwash after every 500 gallons for at least 15 minutes with at least 5gpm
• They also noted the carbon would remove chlorine at first but eventually would stop, the iron trapping in the media would continue to work
• pH above 6.8 (mine is 7.4)

My questions are:

• Given I have sequestrant in the water now, is the air-injection enough to overcome the ion-bonding? I fear not...
• If not, would a hydrogen-peroxide injection tank oxidize the sequestered iron if injected on the way in the iron-filter
• Is there a reliable way to test the iron level in sequestered water using an at home test kit such as Taylor's Midget Comparer? I need a way to check the iron pre/post filtering.

I do understand this would be a slow process as the filtered water would be re-mixing with the unfiltered water slowly diluting the iron. I also appreciate it would be cheaper to just replace the water, but let's ignore the economics of it for the moment.

Thoughts?

 

[Texas Splash]

I'll tag @JoyfulNoise for some technical feedback on the specifics of your proposal, but will add a few general comments. You are correct that the sequestrant makes it more difficult to separate the iron from the water. In addition, the best filtration results, for those without the filtration you have, is to filter it (via polyfill) while the iron is precipitated out of solution either due to the excessive iron levels, elevated pH, and/or elevated FC. Each of those components impacts filtration success. But you have the right idea - remove as much as you can now. Your process is a little more involved than polyfill, so perhaps Matt will have more thoughts to help.

Welcome to TFP!

 

[poologant]

Thank you for the quick reply! I look forward to the additional info.

Also, been a lurker for a longtime, learned everything from this site!

 

[blackout]

Knowing nothing about pools when we had ours built while also being worried about everything, I bought this combo and use it every time I add water:

Pentair Pentek 150469 Big Blue Filter Housing, 3/4" NPT #10 Whole House Heavy Duty Water Filter Housing with High-Flow Polypropylene (HFPP) Cap and Pressure Relief Button, 10-Inch, Black/Blue https://smile.amazon.com/dp/B0045LQ...i_i_6HV0EQD28K6HHY3Q1NNH?_encoding=UTF8&psc=1

Pentair Pentek RFFE10-BB Big Blue Water Filter, 10-Inch, Whole House Radial Flow Iron Reduction Replacement Cartridge, 10" x 4.5" https://smile.amazon.com/dp/B00NADB...i_i_YMJ7VSHSZYD876115M73?_encoding=UTF8&psc=1

Our municipal water tested slightly high last time I saw it so I purchased this as insurance. I have a fitting and a quick connect on it for my hose and I bet one could rig up a submersible pump to cycle water through in a pinch. Or poly fill on the cheap, but this solution is set and forget for all fills.

 

[poologant]

Knowing nothing about pools when we had ours built while also being worried about everything, I bought this combo and use it every time I add water:

Pentair Pentek 150469 Big Blue Filter Housing, 3/4" NPT #10 Whole House Heavy Duty Water Filter Housing with High-Flow Polypropylene (HFPP) Cap and Pressure Relief Button, 10-Inch, Black/Blue https://smile.amazon.com/dp/B0045LQ...i_i_6HV0EQD28K6HHY3Q1NNH?_encoding=UTF8&psc=1

Pentair Pentek RFFE10-BB Big Blue Water Filter, 10-Inch, Whole House Radial Flow Iron Reduction Replacement Cartridge, 10" x 4.5" https://smile.amazon.com/dp/B00NADB...i_i_YMJ7VSHSZYD876115M73?_encoding=UTF8&psc=1

Our municipal water tested slightly high last time I saw it so I purchased this as insurance. I have a fitting and a quick connect on it for my hose and I bet one could rig up a submersible pump to cycle water through in a pinch. Or poly fill on the cheap, but this solution is set and forget for all fills.

Thanks for the suggestions!

So, interestingly enough, I already have the Pentek Big Blue filter (the 20" even). However, different from your use case, I was trying to run my existing water thru it as I already have a pool with iron. Unfortunately, I think this filter will only address ferric iron (already oxidized) and not ferrous iron (invisible, in solution, not oxidized). If my iron oxidizes, it rapidly stains the pool before I can really even attempt to filter it out.

Hence why one of my core questions is: "would a hydrogen-peroxide injection tank oxidize the sequestered iron?"

If so, I could keep it in solution, run it thru an injection tank and then filter it out through the Big Blue or some other iron filter. I will concede this may not be cost effective, but right now I'm just trying to understand my options.

 

[poologant]

For anyone who is in the sad position I am in, I think I have an answer to at least this question:

• Is there a reliable way to test the iron level in sequestered water using an at home test kit such as Taylor's Midget Comparer? I need a way to check the iron pre/post filtering.

After corresponding with SimpleLabs/MyTapScore (3rd party water testing), even their iron specialty test would not produce reliable results with sequestrant. So I don't believe it is possible without really high-end testing. If I'm wrong, please let me know.

The reason I wanted to test the sequestered water was to validate several claims:

• Claim - Jack's Stuff would "clump" sequestered iron to a filterable state.
• Claim - Culator could filtered sequestered iron.

Presently, while I suppose "some" sequestered iron could be filtered out, I'm not sure it would be a meaningful amount. In other words, if only 1% of total sequestered iron was filtered the claims would be technically true but useless as a long-term solution.

I really wanted testing data to put a real world percentage to the claims.