Yes, another Iron in water thread

Trifive

Member
Mar 17, 2017
22
Spring, TX
Hi all,

I've had my pool one year ago this week (Feb.15 2018), and I've noticed the drain grills and certain parts of the Polaris turning brown. I know this to be caused by iron (although I don't know what my iron level is). My water is crystal clear and I keep all my values in check every few days. I use the BBB method as well. My question is this: What can I put in the water to prevent this or clear up the brown stains on the plastic parts? I've read all the iron threads and they mostly are about people with brown or discolored water from horrible sources like well water. I filled my pool with city water here in Houston. I don't buy squat from pool stores without checking here first so Thanks for any suggestions!
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
What can I put in the water to prevent this or clear up the brown stains on the plastic parts?
Even though you aren't aware of any iron in the city water, you seem pretty certain it is iron that is causing the brown color on your drains & Polaris. When it's just a localized area, some folks will try some vitamin C tablets crushed in a sock and held against the area for a while. An ascorbic acid treatment can be applied when the staining is more wide-spread. But just to be sure, you might try that vitamin C trick in an area first just to confirm. In the meantime, check to make sure the pH isn't too high. In fact, an elevated pH can aggravate the situation. Same with a high FC level. So depending on your current CYA, make sure the FC isn't too high. Just in case, here's the TFP Pool School - Metals in the Water and Metal Stains page for you. There are a lot of good threads in the forum about folks who go through special accommodations to filter their water to physically capture some iron. You might do some reading on that as well. Lastly, if you do confirm the staining is from iron, a good sequestrant will be required to control the iron and keep it from precipitating-out onto pool surfaces.

Let us know if you have any questions and how the vitamin C process works.
 

Trifive

Member
Mar 17, 2017
22
Spring, TX
Thank you...I took a sample to a pool store that has one of the testing kits that that spins the water. It's a very expensive brand and it tests for iron. Here's the results:

FC 3.93
CC .59
PH 7.3
Cal 247
TA 41
CYA 3
Copper 0
Iron 0

I need to get my CYA back up as the rain water has destroyed that. But they mentioned that my Total Saturation Index was high (.139?? can't remember) and asked if this used to be a salt water pool. Not sure what that meant. But looks like no iron in the water per this test. So what would make parts of the polaris and drain screens turn brown while the rest of the water is clear?

- - - Updated - - -
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,405
Laughlin, NV
Did you do the Vitamin C test that Pat explained?

Would not concern myself with any of the pool store test results. Typically not very accurate.

You do have your own proper test kit, right?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
15,866
Tucson, AZ
Thank you...I took a sample to a pool store that has one of the testing kits that that spins the water. It's a very expensive brand and it tests for iron. Here's the results:

FC 3.93
CC .59
PH 7.3
Cal 247
TA 41
CYA 3
Copper 0
Iron 0

I need to get my CYA back up as the rain water has destroyed that. But they mentioned that my Total Saturation Index was high (.139?? can't remember) and asked if this used to be a salt water pool. Not sure what that meant. But looks like no iron in the water per this test. So what would make parts of the polaris and drain screens turn brown while the rest of the water is clear?

- - - Updated - - -
Yeah, I wouldn't put too much stock in pool store testing especially if their using a SpinLab. Unless they are calibrating, servicing and checking the results against known standards, there's a good chance those test results are not accurate. Iron, at low concentrations can be hard to detect but can still stain as the build up occurs slowly over time. Iron doesn't stay in pool water for long periods of time as chlorine almost immediately oxidizes it and causes it to precipitate.

As Pat said, clean the parts off you want clean with Vitamin C (you can even buy a few pounds of pure ascorbic acid on Amazon if you want to have it around) and don't worry about it. Municipal water suppliers are not required under federal law to control iron levels in water as iron is not considered a contaminant. So muni water can have plenty of iron in it to cause staining.
 

Trifive

Member
Mar 17, 2017
22
Spring, TX
Thanks guys. Have not done vitamin C test yet. Haven’t had time. I have the Taylor 2006 test kit. I just took the sample to the pool store because I knew their spin test checked for iron.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,405
Laughlin, NV
Great on the test kit. Can you post up your recent test results?
FC
CC
pH
TA
CH
CYA

I would wait until you do the Vit C test before assuming this is iron.