New user with old vinyl pool

[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!