New user with old vinyl pool

[markwg]

First post

[Watermom]

Hi and welcome to the Pool Forum! Tell us about your pool. Do you have a question that you need help with?

[markwg]

About the pool. 10 years old, 17 x 34 x 3.5 to 5' deep. Vinyl liner, gas heater, one return line. Liner is fading and has some wrinkles but does not leak. Installed a frogger system 2 years ago. Last year I had an issue with phosphates and repeated problems with algae. Algae again this year, brown stains I removed with chlorine shock.

We had a pool in the 1980's and all I ever looked at was chlorine, ph and added algaecide once a week. Never had any problems. Now I add metal free, phos free, check for hardness and alkalinity and shock weekly due to past problems experienced. Seems to be some new issue every year.

Water looks good now, but I heard about your forum and thought I would try it out.

[PoolDoc]

May want to cut back on things.

You're adding metal (copper) via the Frogger, then trying to take it out with the Metal Free. Metal Free contains a chlorine eater (citric acid) and a mystery ingredient (acrylic copolymer) to chelate metals. Some reports indicate that this mystery ingredient is EDTA, which you might be able to call an "acrylic copolymer).

So, you're adding copper, and then adding chlorine which tends to make copper deposit as stains. Then, you're trying to remove the metal by adding citric acid which removes chlorine (if present) before it affects copper at all, and you're adding EDTA which is a weak and fairly ineffective way to try to keep the copper dissolved, even though there's chlorine present. . . . and then you're trying to remove phosphates. Now phosphates only get into your pool one way: you put them there. It may be through fill water (city water can have over 3,000 ppb PO4!), but often it's some pool chemical that CONTAINS phosphates, even though it doesn't a label saying "WARNING: Adds phosphates like crazy!.

In the 80's you probably used cal hypo, which adds calcium which tends to strip copper from the water . . . especially if you add the cal hypo via the skimmer or vacuumed up the dust.

You might want to move back in that direction.

Low phosphates CAN make a pool less susceptible to algae. But before you try to do that, you need to figure out where the phosphate sources are, and decide if you can eliminate them. Otherwise, you sort of end up p$$$ing in your own soup!

It doesn't sound like you're really aware of CYA (stabilizer) levels, even though that's one of the 3 most important numbers (chlorine, pH, and CYA). Read this page:

http://pool9.net/cl-cya/

And then see about getting a K2006, so you can measure what's in the water:

http://pool9.net/tk/

Dealer testing is not that trustworthy, for either stabilizer or phosphates. If you want to look at phosphates -- low phosphates can make it easier to go on vacation without returning to a green pool -- you'll need one of the kits for that, also on the page above

Best wishes!

[markwg]

First post
Thanks for your response. I do check for stabilizer, and added some this spring. I had ask about using metal free when I agreed to install the frogger, and was told it would not be a problem. So, a contradiction but I believe you and will stop using the metal fee. I live in the country with fields front and back, and was told that farmers spraying was probably the source of the phosphates. I have a test kit and check for phosphates every week.

Couple questions please;
Do I need to chlorine shock every week? If so, can I use non-chlorine shock, or alternate between the two?

I have some yellow stains on the white portion of the liner above the water line where it meets the coping.
Any suggestions about how to remove them?

Thanks -

[PoolDoc]

+ Do not use non-chlorine shock. It's expensive, screws up your chemistry, and is only marginally effective.

+ Test your stains with Vitamin C tablets and with Iron Out. See if place tabs or a small pile of I-O will remove the stains. Let us know.

+ Check your fill water for phosphates. Most utility water has some added phosphates, but it's possible (if not likely) that well water might have it, too. Phosphates from farm fields? Not likely, unless you are ALSO getting a bunch of blown dirt and dust.

+ FYI, I just Googled "pool frogger" and didn't find anything with the word "frogger". I was assuming that you have the King Technology pool "FROG" feeder system?

+ As far as we can tell, people selling mineral systems ALWAYS say that the copper won't be a problem. Occasionally, they are even correct.

+ What is your stabilizer level? How did you test? Are you aware that test strip CYA measurements are usually HORRENDOUSLY inaccurate?

[PoolDoc]

Mark, I deleted re-quote, since there was no post. Not sure what you intended.

[markwg]

I added stabilizer according to what the pool store tested and said I needed, 2 lbs. I am having a recurring problem I thought I had cured. I keep getting large areas of grey/or brown stains on the pool floor that do not brush off. Not spots. They clear up when I shock, and after a day I vacuum to waste the residue from the pool bottom. So, algae I assume.

Battled this all last summer. When you told me about the metal free working against the copper in the Frog system, I figured that's what
the problem was. But I have discontinued the metal free and just had it happen again.

The water looks great and tests fine, and I have been testing for phosphates also. Thanks for your help.

[PoolDoc]

As far as I know, all forms of algae can be brushed off. And, metal stains would get worse, not better, when you shock.

Could it be fungus bleed-through? That's the only thing I can think of that would behave the way you describe.

If the ground is damp on the non-pool side of the liner, dark fungal or bacterial colonies will sometimes form next to the liner. The pigment from these will penetrate the liner, and show up on the POOL side of the liner. Very high chlorine levels will bleach out the organic pigment, but only on the surface of the liner. The only solution is to (a) dry out the ground under the liner or (b) treat the area with high levels of an persistent anti-fungal, like a mixture of borax and copper sulfate.

I won't ask you to photograph it since when I've seen it, it was never something you could photograph, unless you have underwater gear and high quality off-camera underwater lighting or flash. But, you might swim down with goggles and take a look -- it has roughly the same color as fungal staining on an old white towel.

Let me know what you find.