Algae or Something Else

kenbob57 · Jun 27, 2012

-Pool has been very clear for the last month since I been keeping the pool covered with a solar blanket, using liquid chlorine and keeping CL at about 9.0 ppm.
-Since Sunday pool has a green tint. So I shock to 25 ppm and turn pump to full speed 24 hrs. Pool holds chlorine over night and only drops a few ppm during the day with the solar cover on but pool not clearing up.
-I have also noticed steps getting more rusty appearance and more stains on bottom (vinyl) that wouldn't scrub out.
-New pump this year.
-Pool heater is 10 yrs old (LAARS).
-I only added water (well) one time this year a few weeks back.

Am I fighting algae or something else?

FC 12.5, CC 0.5, PH 7.5, ALK 120, CYA 50. Only use liquid chlorine.

duraleigh · Jun 28, 2012

Hold a trichlor tab on the stains for a minute or two and see if they lighten. Report back if they do. If they don't, crush up some vitamin C tablets (cheapest you can get) and place them in a sock. hold that sock against the stains for about three minutes and see if the stains lighten up. Report back the results.

kenbob57 · Jul 16, 2012

The stains are algae and the pool is constantly having a green tint.

-keeping the CL at 12 ppm
-never any CC, PH is spot on
-CYA is 60
-do not lose chlorine overnight
-cover the pool with solar blanket during the day so a to minimize CL loss
-CL loss is 2 to 3 ppm if cover is on during the day
-temp is 86
-shock at 25 ppm which clear the pool for a few days
-pump runs 24 hrs (12 hrs slow speed with cover on during the day and 12 hrs high during the night with cover off).

jblizzle · Jul 16, 2012

So you think the stains are actually living algae?

If so, you need to start the shock process, which it sounds like you already did, but maybe did not finish?
For a CYA of 60ppm you need to hold the FC at 24ppm until you pass the 3 tests:
1. CC not more than 0.5ppm
2. Pass the OCLT
3. Water is clear ... this includes not seeing visible algae

Are you brushing the pool while at elevated FC levels?

chem geek · Jul 17, 2012

If it's a clear green, I'm guessing it's iron from the well water. It may be yellowish which against a blue vinyl liner would look greenish.

Swampwoman · Jul 17, 2012

Yes, and if you added well water a while back but didn't replenish any metal sequestrate to keep it at active levels, that could be why you're seeing a "delayed" reaction.

What happened when you used the vitamin c? What caused you to say the stains are algae?

kenbob57 · Jul 17, 2012

All. Thanks for the help.

A. I have never done any metal sequestrate in the 10 yrs I own the pool and have only added small amounts of well water a few times this years. The more I look at the issue and will do the Vitamin C test this weekend I believe the stains are iron related.

B. I shocked (27 ppm) this AM, covered the pool with solar blanket at it hit 100 F outside today. Pool water is 86 F. Pool at late evening was 22 ppm, more blue and no algae on the bottom. So I added a gallon (5.5 ppm), scrubbed and kept the pumping running on high.

Questions:
1. What is best sequestrate process ?
2. With CL staying at about 10 and CYA 60 I struggle why the algae keeps coming back so quickly. I never see CC.

New subject:
3. Pool is vinyl, bottom drain is 8' deep but a foot around drain the vinyl liner has wrinkled and hard to keep clean. I nervous to scrub hard, which is hard to do from the deck, to clear dirt and algae in between the wrinkles. Even when the pool is crystal the area around the wrinkly is always dirty and probably contains algae. Any idea on how to clean dirt/algae between the wrinkles? I don't want to apply to much pressure and rip a wrinkle

Ken

Swampwoman · Jul 18, 2012

Sequestrate is not cheap, so first confirm that you actually need it. If the steps are iron stains, then you add the amount of sequestrate the bottle says, eg with jacks magic pink stuff, I believe the first dose is a bottle per 10,000 gallons -- then add about 16 ounces weekly. However, that will stop further staining if you have an iron issue, but won't do much in terms of the iron stains themselves.
For that, you'd want to read up on the Ascorbic Acid treatment -- I believe there's a detailed article over in pool school.

For the drain area I'm not sure what to tell you so I'll let others chime in.

If you could get an iron test kit from a aquarium store, maybe you could test your well water. If you have pictures of the stains, maybe you could post them?

Swampwoman · Jul 18, 2012

P.s. Re drain, do you mean loose dirt that vacuums up, or something sticking to your liner? I've only had my pool this year, so I have no means to compare (it was a foreclosure swamp with problems) but my wrinkled areas seem to come up squeaky clean -- I dosed to 50 ppm of borates and I've heard this really helps keep vinyl clean so if you haven't already, maybe that's something you want to look into to decide if it would make your maintenance easier. (in my case, I used the ph neural pro team plus supreme, but others have ordered boric acid online or added borax using muriatic acid to keep the ph down. You may wish to check out threads on that.)