Algae Troubles, using TF100 tests

[ducss750]

Happy July 4th everyone and I hope you're enjoying your pools.

I'm using the TF100 tests while SLAMming and still failing the OCLT (FC drop overnight was 2.0) but the CC remains at 0.5. Is this possible or am I doing something wrong?

Had SWG issues, so pool was green when opened a few months ago. I treated with bleach until water was clear, but cloudiness kept coming back in the deep end despite more shocking and last week I noticed algae settling in the seams/deep end when the pump shut off. Bought the TF100 test kit last week, initial test results: FC 5.5, CC 0.5, PH 7.2, CYA 50, TA 150, CH 200, Salt 3000, and started SLAMming 5 days ago. Overdid the bleach at first even though I used the pool calculator (shouldn't have added 5 jugs in one day) and brought the FC level up to 28.5 instead of 20.0 (CYA=50, PH=7.2), I brushed and ran the Polaris cleaner during this time and added some DE. Pool was clear but two days later, I turn the Polaris off to let things settle and I see dead/while algae buildup in the seams, which was fine and what looks like dirt but was probably algae in the deep end and what looks like sand in some places on the steps (pool is around trees but no sand). We vacumn the pool to waste till we can see no more and keep testing.

The FC keeps dropping overnight by 2.0, pool still clear,and I notice what looks like a little more algae accumulation in some of the seams, not much, but still suprising especially given the high FC level. We have had a lot of rainfall the past two days, probably about 2 inches last night. This morning, the OCLT dropped by 2.5 (average of two tests) but the CC remained at 0.5 which was similar to past OCLT tests this past week. It just doesn't seem like it should take this long since there wasn't that much too start with, any thoughts? I'm also wondering if the sand stuff was the start of Mustard algae. This morning tests showed the FC dropped by 2.5 down to 16.0 (will add another jug of bleach today) and pool still looks clear. I might shut the pump off for a few hours and see if algae or anything else accumulates. Any help would be great, thanks.

 

[ewkearns]

Your experience would seem to suggest you have some algae growing somewhere.... maybe a ladder? Steps? Light? You may need to supplement the Polaris's efforts with a lot of brisk brushing of your own.... especially around any trouble areas, as suggested..... You might also insure that you have no dead spots in the pool.

Of course, that is assuming that you have been able to hold the chlorine above the minimum SLAM level at all times. If not, you are doing the chemical equivalent of trying to run up a sand dune....

 

[Texas Splash]

Hello and welcome to TFP! Let me first answer one of your questions by saying that yes, you can still have algae even if your CC is low. That's a common question. Of course while you are SLAMming, don't worry about your PH testing anymore, the high FC will mess it up anyways. You have the right idea about the SLAM, but unfortunately some take longer than others. As you have probably read, the key is to "Maintain" that FC level 24/7, to include running that pump 24/7, until you pass all 3 SLAM criteria. It gets very frustrating towards the end, but you have to remain patient and consistent. Even if it was Mustard algae, you still follow the same SLAM criteria, then after passing that you go to a higher FC level for 24 hrs. So that really doesn't pertain to us right now.

I would simply continue to maintain what you are doing, watching your FC closely throughout the day. While running your pump or vacuum, make sure you sweep all the time to break-up any old or new slime/algae. If you have a ladder, take it out and clean it really well. You did the DE trick, so you appear to be doing what is suggested. Hang in there. The dropping FC during your OLCT just means it's still fighting some organics during the dark hours, so you have to keep fighting. Good luck, and have a happy 4th!

 

[ducss750]

Thanks Texas Splash, I didn't know that about CC <.5 still could mean algae. Will keep at it then and glad to know I'm not crazy, haha. I'm going to act like it was Mustard algae and bring the FC level up after passing SLAM. Thanks for the help especially on a holiday.

 

[ducss750]

Update: It passed the OCLT this morning (I did 4 different tests to be sure...anybody ever get different results when testing the same sample more than once for FC/CC?). When I get back tonight, I'll vacuum and bring it up to shock level for Mustard algae in case the sand stuff on the steps was the start. I'll clean the pool ladder and pool toys with a bleach solution too. I wish there was a way to know for sure if I had the start of mustard algae as I hate to shock a vinyl pool that high after the SLAM. My little one has swimming lessons this week and I wonder at what FC level is OK to swim in? Again, I'm about to bring the FC level from "SLAM level" to "mustard algae level" today.

 

[Divin Dave]

Its safe to swim with FC up to regular slam level. Do not swim at mustard algae level

 

[ducss750]

OK, thank you

 

[AimeeH]

You CAN have algae with CC<.5. I've had visible algae on many occasions with no measurable CC.

And welcome to TFP

 

[pooldv]

+1 on that. I had several patches of algae a few weeks ago after I let my FC drop to 1.5ppm for a couple of days. Water was crystal clear and CC was 0 through the whole SLAM. Took less than a week because I caught it early.

 

[ducss750]

That's interesting to know. This will sound weird, but for the past two years, I've kept the FC level low via SWG and only used test strips and never had problems with algae (although I did years before when I did not have a good pool cover and kept it open). This year I had a green pool when I opened due to SWG issues (which I was amazed at how you can fix those things instead of paying money for a new one), and I think I've been having the same residual algae coming back. Regardless, it's fixed now that I"m using the TF100 and reading what you all say about it.

 

[ducss750]

Update #2: Tonight, I scrubbed/vacuumed to waste, added DE, backwashed, removed the ladder and added bleach to bring up to Mustard algae shock level and will test fc in the morning. I noticed more dead algae on the bottom, some of it looked white and other parts looked like normal dead white algae with dirt in it. I did notice either dirt or live algae in one area of the middle bottom of the pool where it slopes down to the deep end...initially I was worried it was algae, but after passing the SLAM test this morning and since the FC level was still at SLAM shock level, I'm assuming it was dirt. I'll let it drift back down to normal FC shock level and disinfect toys/brushes/pole before they go back in the water.

 

[AimeeH]

Update #2: Tonight, I scrubbed/vacuumed to waste, added DE, backwashed, removed the ladder and added bleach to bring up to Mustard algae shock level and will test fc in the morning. I noticed more dead algae on the bottom, some of it looked white and other parts looked like normal dead white algae with dirt in it. I did notice either dirt or live algae in one area of the middle bottom of the pool where it slopes down to the deep end...initially I was worried it was algae, but after passing the SLAM test this morning and since the FC level was still at SLAM shock level, I'm assuming it was dirt. I'll let it drift back down to normal FC shock level and disinfect toys/brushes/pole before they go back in the water.

You can add DE to a sand filter to help clear dead algea faster but you lose that effect when you backwash it out. I'm reading the order of tasks you posted and thought I'd remind of that.

 

[Steve-in-VA]

Yes add DE after every backwash


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[ducss750]

Update: FC drifted down to 14.0 today (avg about 4.0/day now) and I see a little accumulation of dead algae in one area and that's it. Hopefully this works.