Keeping above 2.5ppm - algae still forming

[MikeInAustin]

Pool owner for three years. After falling into the CYA death spiral, I drained the pool in the winter and refilled. Made the switch to the bleach and have been keeping my FC level above 2.5 for a month. I added a floater with 1" chlorine tablets for a week while I was out of town. Since my return, I've been adding a 2 cups of bleach every other day to keep it between 2 and 5. The CC level is always 0 when tested with the TF-100. I run my pump at full speed for 1.5 hours and then for about 10 hours, I dial it down to about 1/2 speed. I've been brushing every other day...which seems excessive. Nobody else I know that has a pool brushes more than me. However, I missed 2 days until tonight. I tested the water before brushing:

FC: 4.5
CC: 0
pH: 7.5
TA: 7
CYA: 40
Temp: 76F

After brushing, you could see a distinct line between the brushed and non-brushed area. The algae was everywhere. Am I missing something? Does the low speed on the pump not circulate the water good enough? Any help would be appreciated.

Thanks,
Mike

 

[jblizzle]

With a CYA of 40ppm, the FC should never be below 3ppm, see the FC/CYA Chart ... sounds like you have not been keeping it high enough.

Time to follow the ShockLevelAndMAINTAIN Process to eradicate the algae.

 

[PAGirl]

The minimum for 40 is 3.Have you ever done an OCLT? Are you able to dose every day?

 

[Texas Splash]

Mike, I agree with Jason. I'm afraid that the FC was consistently just too low and allowed algae to grab-hold of your pool. Time to SLAM. Good thing is your water doesn't seem to be too terribly bad, and you're still at a low springtime CYA, so if you maintain an FC of 16 and stay faithful with the cleaning, sweeping, and filter rinsing, you should make good time. Just make sure to pass ALL 3 SLAM criteria before you let the FC below 16. Good luck!

 

[MikeInAustin]

Thanks for your help guys. Much appreciated.

 

[MikeInAustin]

I've been SLAMming for about 5 days. The pool looks beautiful, but I'm losing about 10ppm of chlorine between sunrise to sunset. (Usually 25 to 15). So I checked the CYA again and it's 20, not 40. I haven't really had the opportunity to do the OCLT since at 9PM, I'm at the minimum shock level and add 2 gallons of bleach. I thought for the past few days it was due to all the algae being consumed, but now I think the CYA level is the problem. I added enough CYA to get it up to 40 and I'll test again tomorrow.

Does anything above sound not correct?

Thanks,
Mike

 

[Texas Splash]

That's a great catch Mike! The TX sun is making itself known, and I have no doubt a low CYA will result in additional FC consumption. Give the stabilizer (if it was granules) 24-48 hours before re-testing and trying that OCLT again.