iron in water

302harrison

Active member
Jun 26, 2013
39
Irmo, SC
I have some staining in my pool that I have determined is iron by using a vitamin C tablet. I read online that this comes from well water. We don't have well water. It can also come from rust of pipes due to low ph. I was having some problems with the ph and didn't do a great job keeping up with that over the winter, so I'm feeling like that is what it is. Do I need to get a pool company here to look at it, or can I fix this myself? If I remove the stains and get the ph balanced, will the rust continue or stop? thanks so much! feeling like a dummy.
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,173
FL panhandle
It is possible to have iron in city/municipal water, some even use wells as a source. It is possible for very low levels of iron in your water source to slowly build up over time to the point there is enough iron to cause stains. In these cases partial water change will dilute the iron enough to prevent stains.

What pipes do you think could be the source of iron?

Don't feel like a dummy, iron in the water is one of the most difficult things to manage in a pool.

Have you seen this article in Pool School?
Pool School - Stains in Your Pool
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,471
SW Indiana
Normally pipes that cause the iron in the water are water company lines that service an area. It is usually worse in sparsely populated areas or near the edge of the companies service area. Nothing you can do about that.
 

Miamipool

Active member
May 14, 2016
26
Miami
I have the same problem. I think my iron is from lawn irrigation which is on a shallow well, its doesn't spray into the pool but when its windy I guess enough gets in over time. I'm sure it could be from another source. I use a sequestrant and just dump some water when it gets really bad. The annual vitamin c cleaning, dump 1/8 of the water and add sequestrant usually keeps it in solution. Watch out when using algaecide or other pool store chemicals, these have caused problems before I found TFP. Lots of good info in the stains thread and you could also do a search. good luck, lots of smart guys and gals on here to ask.
 

302harrison

Active member
Jun 26, 2013
39
Irmo, SC
Ok. So I'm ready to start the ascorbic acid treatment to get rid of my iron stains. It says you may want to add polyquat 60 to keep algae from growing. I don't have any. Is this step necessary? It says I can start raising the chlorine level after 24 hours. Will algae likely grow that quickly? Or can I just treat and then bring the chlorine back up without adding the polyquat? (It also says to avoid shocking for two weeks, so I guess if algae does start to grow, that could be a problem). Advice?
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,173
FL panhandle
That is the reason for the polyquat. There is less risk of algae getting a foothold with colder water, 60 and under.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
The Poly is insurance during the period when your FC is zero or extremely low during/following the AA. Will algae grow? Hard to tell based on how long the FC was reduced and the water temps. Shocking is avoided for a couple weeks in-part because it will reduce the effectiveness of the Poly. If you had to shock/SLAM, it could very likely result in stains as the high FC level reacts to the iron. This is why it is suggested to increase FC slowly and monitor the water for any indications of interaction between the iron and chlorine.
 

Mr Bruce

TFP Guide
Mar 24, 2014
2,095
Greenville, SC
IMO you can skip the polyquat. It's still cool enough that algae growth is very slow/non existent. I'm keeping FC at ~some~ right now and not worrying about it too much.

You aren't going to get a giant algae outbreak with water temps in the 50s. (This assumes you aren't heating your water, etc.)
 

302harrison

Active member
Jun 26, 2013
39
Irmo, SC
I treated the iron staining, and the pool looks beautiful! Who knew the liner was still so pretty under there? I'm assuming I need to continue with regular use of a sequestering agent. My question now is how often to apply this. Thanks!
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,173
FL panhandle
There isn't a set interval for sequestrant additions. That is part of the challenge of managing iron. If you add it quickly when you start to see signs of staining it will often lift the stains. A partial water change or two may dilute the iron content enough to eliminate the staining altogether if it is a longterm build up.

When partial draining a vinyl pool it is important to leave a foot of water in the shallow end to prevent liner shift, shrink or other problems.
 

Other Threads of Interest