My Iron Stain Removal

[RPSalty]

Yes, I use a speed stir.
@1300
Latest Test Result Summary:
FC: 2.0 (13 minutes ago)
CC: 0.5 (13 minutes ago)
pH: 7.7 (13 minutes ago)
TA: 110 (13 minutes ago)
CH: 475 (13 minutes ago)
CYA: 70 (13 minutes ago)
SALT: 3100 (13 minutes ago)
TEMPERATURE: 74° (13 minutes ago)
CSI: 0.16 (13 minutes ago)

 

[JoyfulNoise]

The typical media loading for a DE filter is 1 lb of DE for every 10 sq ft of surface area. So you really only need about 5-6 lbs of DE. I would err on the side of caution and only use 5lbs. The picture looks like you are overloading the filter with DE and that will greatly affect head loss. Also there is a lot of leaf debris in there. You might try adding a polypropylene hair net around the skimmer basket to capture course debris. A package of 100 hairnets runs about $6 on Amazon and I change mine maybe once every week or longer. It makes a huge difference in the amount of debris the filter sees. When I clean mine, all I ever see is old, grey DE and the occasional hair strand, that’s it. With hair nets and minimal landscaping, I never backwash my filter. I just clean it out twice per year.

 

[ajw22]

I did not use poly-fill.

This may be helpful...

Iron Fill Water Filter - Further Reading

www.troublefreepool.com

 

[RPSalty]

Go figure, I took my chlorine jug up for a refill and figured I'd take a pool sample as well. PAP gave me a Smiley Face Congratulations You have perfect water! The only values that agreed with mine were the FC and pH. Their CH was 280 and TA was 80.

I'll click over to the threads on how to test water, perhaps I am doing something wrong.

EDIT: Apparently I'm doing the testing correctly, keep adding drops until there is no color change.

 

[AndyTN]

That ph of 7.7 is still a bit high for where you want it so soon after the AA treatment, I would think. The higher the ph, the faster the iron will precipitate again. You want it to precipitate to the polyfil but over a long period of time. Are you trying to have the ph at that level?

 

[RPSalty]

Negative, will add acid after I test tonight. I won't have the poly fill until tomorrow. I may have added the SC-1000 too soon.

 

[setsailsoon]

Go figure, I took my chlorine jug up for a refill and figured I'd take a pool sample as well. PAP gave me a Smiley Face Congratulations You have perfect water! The only values that agreed with mine were the FC and pH. Their CH was 280 and TA was 80.

I'll click over to the threads on how to test water, perhaps I am doing something wrong.

EDIT: Apparently I'm doing the testing correctly, keep adding drops until there is no color change.

I'd bet on your test results over pool store any day with the test kit you're using!

 

[RPSalty]

@1800
Latest Test Result Summary:
FC: 2.5 (5 hours ago)
CC: 0.5 (5 hours ago)
pH: 7.7 (5 hours ago)
TA: 110 (5 hours ago)
CH: 475 (5 hours ago)
CYA: 80 (5 hours ago)
SALT: 3100 (5 hours ago)
TEMPERATURE: 74° (5 hours ago)
CSI: 0.14 (5 hours ago)
Added 2 cups acid.

 

[RPSalty]

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Maintenance 02-18-2021 @ 09:12 AM
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Brushed
Pressure: 5

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Test Results 02-18-2021 @ 08:59 AM
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Free Chlorine: 4.0
Combined Chlorine: 0.0
pH: 7.5
Total Alkalinity: 100
Calcium Hardness: 475
CYA: 70
Salt: 3100
Temperature: 73°F
CSI: -0.10

Yesterday was mostly overcast and the pump ran all night with SWG at 50%. That would be my explanation of the increase in FC as I did not add liquid chlorine yesterday.

 

[RPSalty]

The typical media loading for a DE filter is 1 lb of DE for every 10 sq ft of surface area.

This is the replacement label that came with the modification kit. That's all I had to go by.

 

[RPSalty]

Poly-fill added to both skimmers, main drain secured. What a great way to repurpose old pillows!

 

[RPSalty]

@1730
FC: 1.5
CC: 0.0
pH: 7.4
TA: 90
CH: 450
CYA: 70
SALT: 3000
TEMPERATURE: 77°
CSI: -0.23

Pool looks great, staining still not visible, water is clear. Today was sunny in the 80's. I reduced the SWG to 30% this morning, but I put it up to 50% this evening. However I cycled the pump off until l tomorrow.

I do not see any red in the poly-fill. Have I defeated this whole process by adding the SC-1000?

 

[JoyfulNoise]

You’d have to go high on chlorine and pH to see if iron will precipitate. In the old days, you could grab a cal-hypo puck (not powder and not the trichlor pucks commonly used today) and place the puck on top of the poly fill. The combination of a small volume inside the skimmer plus high FC and pH from the puck would cause any iron in the water to precipitate out. The poly fill would then capture it.

 

[RPSalty]

So do I want/need to do that? It's not that want to see red, I just thought it was supposed too. An earlier poster suggested keeping the pH lower so the red doesn't stain again. How long will I leave the poly-fill in?

 

[setsailsoon]

You’d have to go high on chlorine and pH to see if iron will precipitate. In the old days, you could grab a cal-hypo puck (not powder and not the trichlor pucks commonly used today) and place the puck on top of the poly fill. The combination of a small volume inside the skimmer plus high FC and pH from the puck would cause any iron in the water to precipitate out. The poly fill would then capture it.

That sounds like a great way to go... I'll try it too!

 

[mguzzy]

That sounds like a great way to go... I'll try it too!

Dang I wanna try, too! But I gave all my chlorine pucks away to the homeless dudes that stand at the stop light.

 

[JoyfulNoise]

So do I want/need to do that? It's not that want to see red, I just thought it was supposed too. An earlier poster suggested keeping the pH lower so the red doesn't stain again. How long will I leave the poly-fill in?

No, you don’t. I was merely making the point that it takes high chlorine and pH to cause precipitation. You pH and FC are both low enough for iron to remain fairly soluble in the water and the addition of the SC-1000 is further making it more soluble.

You can leave the poly fill in as long as you like. If it’s not doing anything after a few days, take it out and save it for another time.

 

[RPSalty]

Dang I wanna try, too! But I gave all my chlorine pucks away to the homeless dudes that stand at the stop light.

Tough crowd! All I seek is removing the staining which I accomplished. At this point is when/should I bring the FC and pH up to the recommended levels for a SWG pool.

1/2" of rain and mostly overcast all day.

Todays readings, at lunch my K-1000 test indicated FC was still dropping so I added 16oz of chlorine. The copy/paste is chronologically reversed.

Test Results 02-19-2021 @ 06:00 PM
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Free Chlorine: 3.0
Combined Chlorine: 0.5
pH: 7.6
Total Alkalinity: 100
Calcium Hardness: 425
CYA: 60
Salt: 3000
Temperature: 75°F
CSI: -0.02
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Chemical Addition 02-19-2021 @ 03:05 PM
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+ 16 FluidOunces of Bleach
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Test Results 02-19-2021 @ 09:56 AM
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Free Chlorine: 1.0
Combined Chlorine: 0.0
pH: 7.5
Total Alkalinity: 90
Calcium Hardness: 450
CYA: 70
Salt: 3000
Temperature: 76°F
CSI: -0.15

 

[JoyfulNoise]

If the water isn’t being exchanged with iron free water then you’re going to need to change your overall game plan. You can’t go back up to SWG levels abs higher pH as that will bring the staining back. Usually when one has to deal with iron issues, you have walk the tightrope of low FC and low pH to keep the iron in its solubility range. That of course means you’ll be setting yourself awfully close to the algae bloom territory and you’ll s using a lot of acid to keep your pH under a tight lid which will lead to TA falling abs then the possibility of the baking soda/muriatic acid yo-yo.

You have to pick your poison and either live in constant chemistry maintenance mode OR bite the bullet and drain & refill with as much iron-free water as you can. You live in FL so rain water is free. Just lower your pool water level an inch and let rain fill it up. Keep doing that and over time you’ll get the iron out. If your household supply can get you low iron water, then use that too. It’s either that or play permanent pool-boy-chemist all year long.

 

[RPSalty]

LOL. I am kind a done with the chemistry experiment. I don't mind testing with the K-1000 daily to ensure the FC and pH are present and constant. But doing the full testing, twice a day, well my wife wants her counter back.

Before starting this process, I was keeping the FC 2-3ish and the pH 7.5ish per what I read that causes the staining. The SWG makes it easy to regulate the FC and I was adding about a cup a day of acid. Once a week do the full test. It was an easy enough routine. The TA, CH and CYA never changed that much.

So what I am gathering, by keeping the iron soluble, I can't filter it out. If I raise the FC and pH to the recommended levels, the iron will precipitate and become filterable but may/will also stain the pool surface.