Does sequestrant mess with filtering out iron?

grogg

Member
Apr 26, 2020
8
Bedford, NY
I have high iron well water. It turns brown in the pool.
When I set up my above ground vinyl pool each year, usually I filter out the iron with a polyfil bucket. Usually it works great.

This year I bought a larger above ground pool (went from 1700 gal to 5000 gal) and bought a much larger filter (2450 sand filter - details below), and added Metal Free - a sequestrant - to my iron-rich water, before I started filtering, and the filter is not removing the iron.

Will the effects of this sequestrant wear off so that I can filter out the iron with a polyfil filter? Is something else at play here?

I have been running a sand filter nearly 24 hours a day for 3-4 days with polyfil bucket and sock-filters, and CUlator in the skimmer basket, and my water is still brown, not lightening, and barely any staining on the DIY filters. Usually it takes 2 days total and the filters turn brown immediately, so I assume the sequestrant is preventing the filtering because it is "locking up" the iron.

My levels aren't perfect - will readjust shortly:
PH 7.8
FC 0.8ppm
CC 0.2 ppm
TA 100ppm

Westchester, New York
AG Intex 5000 gallon Vinyl Pool 16' diameter x 48" high
Sand Filter 2450 GPH 0.75 hp
TAYLOR TECHNOLOGIES INC K-2006 TEST KIT COMP CHLORINE FAS-DPD

20200428_122357.jpg
20200428_122350.jpg
20200428_122328.jpg



Thanks!
 
Last edited:

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,421
Evans, Georgia
Yes, I believe you defeated your own purpose by adding that sequestrant. For the polyfil fitering to work the iron needs to be oxidized and available. You've sort of "hidden" it by the sequestrant.


I'm not positive this will help get the iron out of suspension, but I'd go ahead and raise your FC level because you're risking algae for sure otherwise.

Maddie :flower:
 

grogg

Member
Apr 26, 2020
8
Bedford, NY
Thanks. So you are recommending I shock the pool to get FC to 10 to break down the Metal Free Sequestrant? I assume by adding liquid chlorine or even (gasp) powdered pool shock? Issue seems to be Metal Free is polymeric not HEDP. Anyone know how to breakdown Metal Free polymeric Sequestrant? The bottle says you need to re-apply it weekly, which makes me hope it breaks down on its own.

This mornings readings are:
FC 1.8
CC 0.2
PH 7.6
ALK 100
CYA 0 (the black dot never disappeared)
 
Last edited:

duraleigh

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Apr 1, 2007
34,246
Sebring, Florida
So you are recommending I shock the pool to break down the Metal Free Sequestrant
No, Yippee Skippy is suggesting to simply raise your chlorine level.


By raising your chlorine level to about 2-4 ppm, you get some protection from algae (which you REALLY need) and the extra chlorine will quicken the reduction of sequestrant in your pool.

Without the results of a current CYA test, we are just guessing at what FC level you should be. Can you report CYA?
 

grogg

Member
Apr 26, 2020
8
Bedford, NY
Thank you for clarifying! CYA reads as zero (black dot never disappeared). The kit is from last summer - I might want to buy a new one?

Currently I am adding chlorine with clorox brand pool tabs (label says trichloro 95% (available chlorine 85%)

but after reading these forums I see that I should go buy some liquid chlorine instead.

This morning's readings are:
FC 1.8
CC 0.2
PH 7.6
ALK 100
CYA 0 (the black dot never disappeared)
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,421
Evans, Georgia
Don't use ANYthing by Clorox labeled "Xtrablue".......that's copper! Ugh! They don't make that clear on the label but you don't want to be adding copper to water.

Liquid chlorine, like Walmart's Pool Essentials 10% found in the pool aisle is a good source. Get some today!

Maddie :flower:
 

grogg

Member
Apr 26, 2020
8
Bedford, NY
Yikes! Thank you! I just pulled that clorox stuff out and threw in my flipping frog - does that have copper? I will pick up liquid chlorine today.

(Sounds like the pool industry is full of snakeoil!)
 

duraleigh

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Apr 1, 2007
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Sebring, Florida
Your CYA test is still valid......that test is inert and virtually never goes bad. get 30 ppm in your pool right away.
 

grogg

Member
Apr 26, 2020
8
Bedford, NY
Oops! Wish I had read this before I went to the pool store. Back I go!

I asked for Liquid Chlorine and they sold me this (see image): hope it is right!
Sodium Hypochlorite
chlorine.jpg


To raise my CYA, is this the right stuff?
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,421
Evans, Georgia
Yes, you've got liquid chlorine and cya pictured. Put your desired amount of CYA granules in an old stocking or sock and hang it on a pole in front of a return. Measure out the liquid chlorine and mix in the water well. Use PoolMath to guide you on proper amounts based on desired goals.
 

grogg

Member
Apr 26, 2020
8
Bedford, NY
Great! Thank you! I will keep my levels right and wait. The pool has started getting darker, and the polyfil filter is starting to darken, so I figure that means the sequestrant is starting to wear off, and the iron is coming out of solution and finally getting filtered out. But taking a lot longer than past years. I guess the pool is 3 times the size of previous years, but seems the time to filter is exponential not just 3 times. Anyway I will just be patient, keep my levels right, and try not to judge myself because my pool water is brown... not sure I can say the same for my neighbors :)
 

grogg

Member
Apr 26, 2020
8
Bedford, NY
Update: I was patient and a good boy, and I kept my levels right with the PoolMath app, using no chemicals other than liquid chlorine, soda ash, and muriatic acid (and some cya to get it to 30), and I watched as slowly that sequestrant wore off, finally allowing the polyfil bucket on the outflow, old socks on the inflow, and culator in the leaf skimmer to do their work.

Attached the images. TFP to the rescue again- simplicity wins!

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THANK YOU THANK YOU THANK YOU FOR YOUR ADVICE!
---
So,now that the pool sharks have filled my garage with a bunch of chlorine+Crud products I have learned not to use, my problem is: what to do with a bunch of poisonous crappy pool products?
 
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YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,421
Evans, Georgia
OH yeah!!! :goodjob:

Just wondering... you say it took longer this time than past years.... did you add sequestrant in past years? I would think for sure that contributed to the big slow down.

Looks great!

Maddie :flower:
 

grogg

Member
Apr 26, 2020
8
Bedford, NY
I never added sequestrant before. This year I bought a bigger pool, and it was taking so long to fill that the water started to turn brown before the water hit the pool outflows, so I got scared of staining and threw some sequestrant in. Big mistake! It added at least a week to the filtration process, disappointed my kid, and an embarrassed spouse (covet not thy neighbour's clear pool).

Thanks for your help @YippeeSkippy @duraleigh and @mknauss

Ready for summer camp, quarantine-edition!
 

setsailsoon

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Oct 25, 2015
3,330
Stuart/FL
Wow! Another great TFP success story! It's normal for people to think the expensive products and potions sold in pool stores must be better. Unfortunately that just not the case for pools. Very simple products available cheap from big box stores are the way to go and that's what TFP methods are all about.

Welcome to TFP and a great-looking, easy, and safe TFP pool from now on!

Chris