To sequester or not??


New member
May 8, 2016
Newnan, Georgia
Okay, so I kept chlorine going all winter, but honestly didn't keep the pool balanced otherwise. 😢
So, I noticed that the steps were beginning to turn brown. My chlorine had been a tad low, so I shocked the pool. Nothing changed, if anything, it spread. I took a water sample to the pool folks and they said I had no iron or copper. They had me balance everything, but drop chlorine level, then do ascorbic acid treatment.

I used 2 lbs and it lifted some and just streaked in other areas. I let the pump run for 2 days, back washed quickly, then added more AA. The pool is now the cleanest and clearest that it's ever been. Okay, so the pool folks told me that, since it wasn't metals, I shouldn't use a sequestering agent. I tested tonight and chlorine is 0, pH is 7.2 and TA is actually a bit high, at 1100. I began increasing my chlorine slowly, as told, which is my chlorinator set at 3.

Here's my concern. Although I was told no sequestering agent, everything here says that I should be using one. I am afraid of the stains coming back and don't want to mess this up. I also see a clear film, in my skimmer. I assume it's from the AA, but have never seen it before. What is it and what should I do from here?

Any help would be greatly appreciated!

Texas Splash

Mod Squad
LifeTime Supporter
TFP Expert
Hi Julie and welcome to TFP! :wave: Well, you're correct about needing sequestrant IF you have metals. One problem is the pool store's testing can be inconsistent at best, however metal testing is one we often have you go there for. But if you took a sample from your pool water, it may have given a bad results as the metal had already precipitated from the chlorine. I would suggest having the metal tested from the source .... right from where you get the water (garden hose, etc). That may provide a different reading.

For the rest of your levels, you'll need your own proper test kit, because before doing any metals treatment you definitely need to ensure your water is algae-free, otherwise you'll be right back doing the whole thing over and wasting your money. Please see the TF-100 link below in my sig. Also, here is the TFP Pool School - Metals in the Water and Metal Stains page just in case. Keep in touch and let us know how things are going or if you have any more questions. Have a nice day.


LifeTime Supporter
TFP Expert
Jan 6, 2010
San Dimas, CA (LA County)
Yes, sequester.

What has happened is that the Ascorbic Acid has bound itself to the metals. Currently, they are sequestered, so the store test showed none. Sequestrants are like the hard candy shell on M&Ms. The chocolate's still there, you just don't see it. If the pH gets shoved too high, it'll reappear unless you wrap a better shell around it.

I always like this picture. Look at it closely. Yellow Stains