Reoccurring Algae

[eric_engineer]

I have a reoccurring algae problem that I did not have last year and I'm trying to figure out why. I was lazy a month ago when it was rainy and I came out to long strips of algae at the bottom of my pool so I followed the SLAM instructions here. I scrubbed it, vacuumed it, hand scrubbed the seams underwater, and raised the FC level above 10ppm and kept it there by testing every few hours with my fas-dpd kit. Eventually I passed an overnight test and all was good. Also during that time my CC level was never over 0.5ppm. I decided to keep my FC level at 4ppm, last year I went 1.5ppm-3ppm though. Now a few weeks later I'm seeing little algae patches every few days that I have to brush away. I always fish out any leaves or debris right away, and I have one of those rechargeable intex pool vacuums to get up debris on the bottom. I check my CC level every...well at least every other day. Oh and today with the algae spots, CC was 4ppm, FC was < 0.5ppm and my CYA is around 45.

The differences from last year that I can think of are:

• had a new baby so not using the pool every day
• added the solar bear so avg pool temp is 85C, I'm sure the algae likes that
• this is the second year of operation, it spent the winter in the garage
• I'm running the pump longer 6hours pump +swg right now
• I had a stocking like liner for my vacuum last year but lost it mid-season this year
• Last year I barely used the scrub brush

Maybe I don't brush it enough? I'm not doing it weekly, but last year I didn't have to at all really. I'm wondering if the higher temperature combined with us not getting in and mixing the water up as much has anything to do with it. Anyway, any advice is appreciated . Thanks for reading my post!

 

[richierich]

Your chlorine level is too low. I know it's counter to what you see everywhere when they say it should be 1-3 but for your pool your chlorine level should be around 7 see chart.

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

 

[Mdragger88]

Hey eric
If your cya is 50 (which it is because you always round up to the next 10) your SLAM Process fc level is 20ppm -not just above 10.
Also in the hot summer sun I would wager that a cya of 50 is not high enough to protect the fc your swg creates so it dipped too low at some point during the day allowing something to grow.
After slam is complete you should raise that to cya 60 or 70 & maintain a higher fc target. Most here with swg’s (myself included) try to keep fc at least around 10% of cya so we have a buffer for extremely sunny days, adverse weather conditions, higher than normal bather loads etc.

 

[derekm]

Replace your bubble wrap cover while you're at it. I had sporadic yellow algae for a couple of summers and finally figured out that it was originating inside some of the broken bubbles, and returned as the weather cooled down and I used the cover more (and the pool less). I replaced the cover and the pool has been perfect ever since.