Start of algae bloom? Update…

[mrm1682]

I’ve had the pool perfectly balanced all season and the last 2 weeks I’ve had relatively clean water. I can see the bottom easily but when inside I can’t see to the other end of the pool. Also when I sweep there’s a brownish dust that gets kicked up. Weekly tests still in check as of yesterday.

FC 8 (had SWCG higher before a party and still hasn’t fallen down; and pool was a little cloudy before the party)
CC 0
pH 7.8
CYA 70
TA 90

I passed OCLT test as well. All of this seems to coincide when I added a bag of salt but I don’t think it’s related.

So is this algae? If so, is it really necessary to SLAM? Or just keep the FC on the higher side?

 

[Texas Splash]

Passing the OCLT is great if performed correctly and the SWG was off. It is odd you noticed changes after adding the salt. Some bags have a few more impurities than others. Your signature is blank. What type of filter do you have?

 

[mrm1682]

Hayward sand filter. It’s the same salt I’ve always used and never had problems.

I tried backwashing last week but no difference. Not getting worse either but not better. Water cleared quickly in the sight glass after about 1 min so I presume the filter is pretty clean but maybe I’m wrong.

 

[Texas Splash]

Depending on the age of the filter and sand, perhaps it could use a good deep cleaning? Might be convenient to do next spring.

Deep Cleaning a Sand Filter

This post will walk you through the anatomy of a sand filter, and then provide a video at the end for how to deep clean your sand filter. The filter used in the photos and videos is a Hayward S180T top mount sand filter. The images are of a similar filter. Obviously not all filters are...

www.troublefreepool.com

 

[mrm1682]

Pool was built last year so only 1.5 seasons so far. I started out last year though with a lot of dirt in the pool before it was backfilled so perhaps it’s dirtier than I appreciate at this point. I’m probably closing in another 6 weeks so but I want to close it clean and not with algae starting.

 

[duraleigh]

So is this algae? If so, is it really necessary to SLAM? Or just keep the FC on the higher side?

I would do as you are thinking and simply keep the FC on the higher side. I think continued (24/7) of your filtration will slowly improve your pool.

It may be dead algae or possibly dirt from the salt but, regardless, I see no reason to SLAM.

Brush daily and run the vac or robot to keep the "debris" suspended up into the pool water and I think your filter will filter it out.......just may take a little longer

 

[mrm1682]

Thanks for the tips.

Tested again today and passed OCLT, FC now 10. pH crept up to 8 and TA tested at 100. Going to get pH and TA better in range because as I understand it, chlorine is less effective when they’re outside of the box. Hopefully get things back in check with some clear water again soon to enjoy the little time left in the season!

 

[wireform]

It would be helpful to all if you can fill in your signature. Looking at your media you have a sand filter. As advised before make sure the filter is clean and Hava good working pressure gauge that rest at "0" when the pump is off. Know your clean pressure and backwash when the pressure goes up 25% of clean filter psi. So you know you can add DE to a sand filter the help catch the fine stuff but watch your psi as you say you have brown dust which will get caught and bring the pressure up faster then normal.
Add DE to a Sand Filter.

 

[duraleigh]

chlorine is less effective when they’re outside of the box

But only by very little. That adjustment would not make my list of top twenty things to do today.

 

[mrm1682]

I feel like I’ve gotten nowhere the last couple of days. Pump is running 18 hrs and FC is 12-14 and has been steady; actually increased the past two days and keeping the SWG at the same level. I’ve passed OCLT past two nights. I brush in the morning and at night. Still have very fine yellow/brown dust that I brush up each time. I backwashed this morning and water is basically clear immediately in sight glass. Pressure is at my baseline and not going up at all. I know I’m not at shock level for SLAM but not sure I should SLAM. Driving me crazy because I’m trying to clear it up for an end of season party this weekend. Should I just grab a bag of shock??

Is this even algae or something else?

 

[Texas Splash]

Was the SWG on or off on those evenings you did the Overnight Chlorine Loss Test?

 

[mrm1682]

Yes. I would shut off the SWG for the last hour the pump was running then test when it shut off. I test again in the morning after pump has been on and then I turn the SWG on.

 

[Texas Splash]

After going back through your posts, I don't see an urgent need to be in SLAM mode. You've passed numerous OCLTs. so that would appear to rule out algae. Your pool & filter are not that old either. I would provide the following options at the moment if you are interested:
1 - Go ahead and go to SLAM level now with liquid chlorine. Won't hurt and with SWG the FC should fall in time for your weekend gathering at which point a little higher FC would be good anyways with a high swimmer's load.
2 - After the party, do one more OCLT to ensure there is no algae, then take the FC up to Mustard Algae level for 24 hrs.
3 - Even though the sand isn't that old, consider a good sand deep cleaning. You could do it now, when you close, or in the spring.

But chemically, at the moment, there appears to be no red flags.

 

[jesse-99]

Kicking up brown clouds doesn't necessarily mean algae either. Sometimes that Crud that gets in the pool just needs to get filtered out, and the only way to get it filtered out is to keep brushing to move that junk around and circulating in the water. (I live in the middle of the woods, so all kinds of junk gets in my pool from the trees). If that stuff sits (without brushing), its harder for it to get filtered. Which is why sometimes brushing might make your water look dirtier initially, but in a way, that's good cause you're allowing that stuff to get filtered because it's not just collecting on the floor of the pool . If you're passing OCLTs, that's a huge positive and you can likely rule out algae I think.

 

[mrm1682]

Thanks for the replies. I haven’t dealt with algae before and this didn’t seem like just dirt to me but maybe it is ‍♂ I’ll probably just stick to brushing to keep things moving along and hope that it clears up and keep my FC on the higher side with upcoming gathering. Deep clean of sand filter seems like a good idea but I don’t want to take things apart now before the party just in case I mess up something.

 

[an1vrsy]

If the dirthas settled on the pool floor then when you brush it it gets suspended back into the water, have you tried manually vacuuming? A good manual vacuum doesn’t take very long and then the pool robot can easily maintain the look.

 

[mrm1682]

It’s not just the dirt though. The water is cloudy. When I look into the deep end I see the drains but it’s just not as clear as usual. Shallow end looks ok.

Did another OCLT and FC last night 14 and again 14 this morning. CC 0.

Maybe it is just a filtration issue and the sand needs a deep cleaning. It’s just odd because this year I’ve hardly had to backwash since pressure was stable and hasn’t crept up. And when I do backwash it clears within a minute so I don’t backwash very long. I’ve read of some folks doing a 3-5 min backwash but honestly that just seems excessive and you’re just dumping chemicals and water.

 

[mrm1682]

Quick update -

So now I’m questioning if it’s mustard algae. It’s a yellowish powder at the bottom of the pool. I was brushing twice a day as FC was in the 12-14 range and it gradually cleared up. I let FC start to drift down and now that I’m at 8, I’m seeing more of the powder at the bottom. Is this a sign of mustard algae? I’m closing up in about 4 weeks once the temps drift down so I’m not sure how crazy I should go.

Also the company that I use for closing will add shock and algaecide as part of the closing. Normally I’d have my FC at normal levels but how do I account for the closing at higher FC levels?

 

[wireform]

It's only mustard algae if you completed the slam with all 3 criteria and you did everything else like vac the pool clean, clean the filter and all to eliminate algae.

 

[mrm1682]

I never did SLAM because I passed several OCLTs. Can you have active algae and pass OCLT? I was never at SLAM levels of FC either…