Green Algae, now cloudy

[kjmelak]

After being away for 3 days, we returned home on Tuesday only to find our pool cloudy & pea green (heavy rainfall in the morning).

I followed the "best guess CYA chart" and shocked to 15ppm using 12.5% pool shock. I've maintained this level ever since.

On Wednesday, I vacummed the pool and backwashed the filter

Yesterday morning (Thursday), the pool was no longer green, but it was still cloudy. I was hoping that the pool would be clear by Friday morning.

Today (Friday morning) the pool is still cloudy! Here are the parameters today:

FC: 15.0
pH: 7.6
CYA: 50
Alk: 100

Should I remain patient, or do I need to do anything else?

Kevin

[mbar]

It can take a while for the dead algae to filter out. Keep your filter running 24/7, keep brushing and backwashing. With a cya of 50 you can boost your chlorine up to 20ppms and see if that helps. Sometimes you just need a little more bleach.

[gonefishin]

please remain patient. Be sure to check your chlorine levels to maintain a shock level(for your cya). ALso continue to vacuum, backflush and run the pump 24/7 (as described above).

It will work...but you need to be persistent.

Do you have an automatic cleaner? if so...that could relieve some of the pain of vacuuming.

good luck,
dan

[Spensar]

That's good progression. It can take a while to get rid of the cloudiness so be patient. I was gone for 5 weeks this summer and the folks taking care of the pool lost control and I am told it went green by neighbours. It was at least shocked back to grey cloud by the time I was back. My pool is around 20,000 gallons too and it took about a week to clear up.

I kept the chlorine at shock levels with liquid chlorine (5%/10% whatever was cheap) and used up half a bucket of calcium chloride too. I backwashed the sand filter twice since the pressure was up by 5 psi when I got back, and rose that much again as it filtered out the dead algae. I've never seen the pressure rise that much before, or that much crud get cleaned from the sand filter before. The pump ran 24/7 too.

Even though my pool wasn't green, the chlorine was being eaten up much quicker than normal, so it was still fighting the bad stuff. If there is still algae around and you let the chlorine levels get too low or zero out for a while it will rebound pretty quickly on you.

Vacumming was very important to clean it up. After a night or day of non-use there was a lot of silt on the bottom of the pool that was vacummed to waste/drain several times. I forgot to change setting from filter to waste once, and a pure stream of grey gunk came out of the input.... that didn't speed things up since it had to settle again. I did hit a point where the chlorine usage was normal so I was just really dealing with the dead algae silt/powder that had to go down the drain. Quite a bit of water was used up doing this - I guess about 4 inches total over the week from a 32x16 pool.

While the water was a mess I only adjusted for PH once because it was really low. Otherwise, I left all other adjustments for after the water cleared up. I must confess a bit of frustration with how tough the cloudiness was, but finally I went out one morning and could clearly see the bottom (and remaining silt!).

[kjmelak]

To update:

Friday: Backwashed filter and vacuumed during the day. Raised FC to 20ppm in the evening.

Saturday morning: water still cloudy. pH has risen to 7.8 - Plan on adding muriatic acid today to lower to 7.6, eventually to 7.4

Would adding 1/2 - 1 cup of DE in the skimmer when backwashing the sand filter help expedite the removal of dead algae?

[Watermom]

Not when backwashing or else you'll just be throwing the DE right out. But, it should help with filtering the dead algae out.

[rastoma]

I followed the "best guess CYA chart" and shocked to 15ppm using 12.5% pool shock. I've maintained this level ever since.

stick with just plain, generic unscented bleach instead of using expensive pool shock which doesn't work any better.

[gonefishin]

stick with just plain, generic unscented bleach instead of using expensive pool shock which doesn't work any better.

But don't overlook bulk 12% chlorine from pool stores (or water treatment stores). I get 5.5 gallons of 12% for $9.00. There are a couple of pool stores and water treatments stores near me that sell chlorine (I'm finding out), but this place has the freshest chlorine with the highest turn over.

happy swimmin'!
dan