Something's wrong

[karmazrevenge]

Hi all,
I have been battling an algae bloom for 2 weeks now. My numbers are as follows:

Chlorine: keeping it at shock level of 20
TA 70
CYA 60
PH 7.8
Calcium: vinyl...don't test
Temp: 85
OCLT 20 night, 0 morning

The pool isn't green anymore, just cloudy gray. Running my sand filter 24/7 on filtration setting, backwashing as needed, brushing and vacuuming daily. Water refuses to clear up.

Is it possible for this to be mustard algae? Maybe a filter problem? Just being impatient?

Any help is appreciated.

 

[Mr Bruce]

SLAM level for CYA 60 is 24. Just to be sure, backwash only when PSI goes up 25%? Any CC showing up? Next time it drops below FC 10 grab a pH test.

That OCLT says you've got a ways to go

 

[nlindelldc]

Wow, that is a serious drop from 20 to 0 overnight! Your are battling something huge, no doubt.

It seems you are doing everything correctly. The only other thing I can think is how often are you testing your FC levels? At first, you may need to test frequently. I would add and then test again in, say, 30 minutes and see what you get.

You've got it on the run it seems. What is your CC's?

Mr. Bruce beat me to it. Raise your FC to AT LEAST 24

 

[Texas Splash]

kr, just to confirm ... are you saying you lost 20 ppm of FC overnight, or that you started at 20 and lost zero?

 

[s1njin]

If the OP is really at 0 FC in the morning, wouldn't you want to drop his pH to 7.2 (or even lower for a little while)? At 7.8 his 'active' chlorine is only 33%; which combined with his lower SLAM level of 20 vs 24 really puts him/her behind the eight ball.

http://www.bluescience.com/swimming-pools/posts/what-does-rain-do-to-pool-water/

 

[pabeader]

With the FC over 10ppm the pH test gets skewed in such a way that it isn't really useful. That's why we have it adjusted BEFORE a SLaM.

I will let others comment on the pH effect, or lack there of, on chlorine effectiveness.

 

[s1njin]

Understood, but in the morning the OP has no FC at all. So why not test the pH in the morning and adjust it (likely down) before dumping more chlorine back in?

 

[Donldson]

What have your CC readings been?

pH has minimal effect on active chlorine levels when CYA is involved. All studies on the effect involve unstabilized water sources.

 

[pooldv]

Totally fine to lower your PH to 7.2 if your FC is 10 or less. I would.

 

[s1njin]

What have your CC readings been?

pH has minimal effect on active chlorine levels when CYA is involved. All studies on the effect involve unstabilized water sources.

Wouldn't that be for the pH that is actively protected by the CYA? So the chlorine outside the protected CYA (based on the level of the CYA) would be more affected?

 

[karmazrevenge]

Hi Texas,

I lost 20 ppm in 10 hours. I WISH my FC had stayed at 20

 

[karmazrevenge]

Duh. Totally forgot to check CC. I'll go do that now and post the reading.

I'll up my FC to 24 (Walmart's going to know me as the bleach queen!). I have a swg but have it off per manufacturer's recommendation not to run it at shock levels. Forgot to mention that too. No clue what my salt level is; I'm waiting for the tester to come in.

Also: vacuuming everyday hasn't produced a lot of gunk being removed after I scrubbed the be-wah-diddly out of it and netted everything I could (man that's hard to do when you can't see!)

BRB with the CC.

 

[Texas Splash]

I lost 20 ppm in 10 hours.

Yikes! Well then .... SLAM it is. If you haven't done a deep clean on your sand, you may want to look at the Deep Cleaning a Sand Filter page. It's helped a lot of people. Test FC often at first so that it doesn't drop so fast on you. You may have to test about every 15-30 minutes for a few times, but once you break thru the big algae wall, th FC will begin to hold much longer. Good luck!

Oh, make sure pH is about 7.2 before hitting it with bleach again.

- - - Updated - - -

Say, don't forget to remove the ladder or steps if possible to inspect and clean them. They are major algae homes.

 

[karmazrevenge]

Update:

Checked FC as soon as I got home. It was 22 when I left for work this morning (after pouring in more bleach) and is sitting at 4 now. Small progress but I'll take it.

When I test for CC the sample barely turns pink and results out at a 1.5.

Just poured more bleach in to get the FC back up. Tested Ph before I did and it came in at 7.2. Can I leave it there for now?

Thanks all,
Kay

- - - Updated - - -

Yikes is right! The ladder is out of the pool - scrubbed it down with bleach twice. I will definitely check out the page for deep cleaning the sand filter. Thinking of adding some DE also just to help things along. Should I wait on that or can I go ahead and do that?

Thank you!

 

[pooldv]

It is fine to add DE if your filter pressure isn't rising too fast already. We recommend backwashing when the pressure rises 20-25% above clean pressure. So, if the pressure takes a couple of days or more to rise 25% the adding DE is fine. Be sure to keep an eye on your pressure.

 

[Texas Splash]

Also, look to see if the ladder steps come apart. Often times each step hold a bunch of algae as the water slips through the cracks.