Iron Staining?

At the deeper end of my pool the liner looks yellowish. The liner is about 6 years old as we replaced it after being here 4 years and it is in good shape. I opened the pool about a week ago and the water is really clear otherwise. Last year was the same thing. I originally thought that it was the water but I dont believe it is. We moved here with the existing pool (20x40 in ground rectangular) and I never knew anything about a pool before. My wife knew a little bit. Can you give me any suggestions? Any help is greatly appreciated. Thanks.
Don Tripp
Clifton Park, NY

Hi, and welcome to the forum!!
If you could supply us with a set of test results taken by a drop-based kit, as well as a list of chemicals (ingredients, not just "shock"), it will help us narrow it down.

When you opened the pool, were there leaves and debris in the bottom, especially where the yellowing is? Does your water contain any type of metals that you know of?

Janet

Janet,
Thanks for getting back to me so quickly. From my drop based test the results are as follows-
Chlorine-3 Sodium Hypochlorite 12.5% from the pool store. I can use no name bleach from Walmart in the future even if it is 6% sodium hypochlorite.
Bromine-6 I dont put this in the pool unless it is considered part of the chlorine from the pool store.
PH-7.2 Sodium Carbonate Which I use A&H washing soda.
Alkalinity-80 Sodium Bicarbonate which I use A&H Baking Soda.
Hardness-130 Calcium Chloride which I use the white ice melting pellets as its the same chemical and has other uses as well as keeping dust down on a dirt road in the summer.
Cyanuric Acid-0 I have tried to use the product from the pool store in the past with actually no results as last year my reading also held at 0 alll summer long.
There are always a few leaves that get into the deep end of the pool every year even though I try to close the pool early enough to avoid them. Also I have acorns there as the squirrels and chipmunks are always getting them into the pool all the time. These are in the deep end mostly.
I dont know of any metals in the water. The water here that I am supplied by the local municipality is spring water as there are alot of natural aquifers locally.

Ok. Using the liquid chlorine from the pool store is great--I wish Louisiana would get caught up with everybody else and make it legal for stores to carry it here!!

You can ignore the bromine reading if you haven't added any to your pool--just pay attention to the chlorine side. I'm assuming you're using an OTO test for chlorine and pH--maybe the 5-way kit from WalMart? If so, that'll work great for now. pH is good, alk is good. You can leave off the calcium chloride, because the calcium does not matter in a vinyl pool, as long as you have "some". 130 is fine.

In order to keep chlorine in the pool, you need some cyanuric acid....is it possible that you cleaned the filter right after you added the CYA last year? If so, it all probably just washed out, because it can take up to 4-6 days for it to dissolve and show up on test results. I would suggest that you shoot for 30-40 ppm, added either through the skimmer very slowly and not tested for, backwashed, or more added, for a week....or you can put it in an old sock and hang it in front of the pool water return, and allow it to dissolve that way.

On to your question......my best guess would be tannins from the leaves and acorns that get into the pool during the winter as the cause for your yellowing. My deep end does that every winter, too, worse in the areas where the leaves congregate. If that's the problem, then getting the pool up to shock level (chlorine of 12-15 ppm with no stabilizer) and holding it there for a couple of days usually will resolve the problem. If not, then you can try crushing up a vitamin C tablet and rubbing it on one of the yellowed areas and see if that lifts the stain.

Janet

Janet,
Again thank you. I did use an OTO 6 way test kit from Walmart. I'll have to get some cyanuric acid from the store and I think I'll use the old sock trick you mentioned as within a week I would probably need to backwash anyway. I really didn't use any cynauric acid last year because like I had mentioned before it wasn't staying and the test kit said a minimum of zero was ok. Before I do the cyanuric acid I will do the chlorine shock level (12-15 ppm) for a few days to try to clean up the yellow in the deep end. Wouldnt do any good to crush up vitamin c tabs as the yellowing is in the deep end about 8 feet deep or so. Can't hold my breath that long can't even swim as I am only the caretaker of the pool for my wife, kids, grandkids,etc. Can you believe it? Thanks again.

If the shocking doesn't do it, then you could still try the vit. C trick without getting in--crush them up, use the other old sock, and tape it to the end of your pole, and maybe apply in that way.

Be really careful not to fall in!!!!

Janet