Algae issue with good numbers

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C

Cbriley

0
Aug 28, 2018
3
Mount Pleasant sc
Hello everyone,
im new here and to owning a pool. Have had the pool since May and no issues until recently. we have a 21'x54 Saltwater LX Round Pool pool with a intex 16" sand pump and SWG (given to me new and never used). A friend has the same setup for 3 years with no problems. The pool is buried halfway(if that matters).

We have been battling algae for about 6 weeks. It starts with a little bit on the bottom of the liner and spreads pretty quick. We have shocked it twice (before finding this site) and both times the algae turns white and we vacuum to waste. Within a week it comes back. I found your site and bought the TF100 after i had shocked it the last time 3 weeks ago. The test kit came and i saw the numbers come down and level off from the shock and after a little balancing (hardness and TA) got all the levels perfect. The levels had stayed the same for 9 days and the pool was clear until 4 days ago the algae came back and is growing even faster. My levels over the last 14 days were:

TC - 4.5
PH- 7.5
FC - 4.5
CC - 0
CH - 300
TA - 80
CYA - 70

Every test has produced these numbers even now the algae is growing. The pool is still pretty clear but its getting the slight green tint. when i brush it, it clouds up but i can still see the detail on the liner bottom. There is no CC and no overnight loss (SWG is running for 8 hours with the pump on 12). We only have a few weeks left i think so we were just going to keep brushing and vacuuming and use it the rest of the season but it seems to be getting worse daily. I know a slam is going to be called for but from what i read here it seems i should have FC loss and CC over .5 with the algae. Am i missing something?

Thanks for any and all advice. I am in Charleston SC and the pool gets sun from 10am until 430 everyday.

Chris
 
Welcome to the forum! :handshake:

When do you do your testing? Just before the SWCG turns on for the day? Is the pool brushed often? Above ground pools tend to have an issue with circulation and thus algae can get a foothold in areas of poor circulation.

If you have visible algae, the remedy is SLAM Process. Brush the pool very well so that the algae biofilm gets broken up and the chlorine can attack it.

I suggest you read Pool School - ABCs of Pool Water Chemistry and consider reviewing the entire Trouble Free Pool School book.

Please add a signature. Read Pool School - Read This BEFORE You Post
Information in your signature will show up each time you post and it makes advice more accurate as we know what equipment we are dealing with.
 
Your FC probably fell below minimum which might explain why you have algae growing. Bump up the FC to shock level for a few days,keep it there and see it improves. If not, you'll need to perform a full SLAM. I usually stay a few FC over my target FC/CYA level just to be safe.
 
hello and thanks for the replies. I've been testing in the morning before SWCG turns on and about 10 hours later when i get home from work when the SWCG has been off about an hour. The numbers have been the same each test for about 9 days. I had shocked the pool and the TF100 came 3 days after i shocked it, so my first test the TC was 18 with 0 CC. I have tested twice a day since then (9 days). I watched the TC come down from 18 to 4.5 over about a week. its been 4.5 for 9 days and still algae.

We brush everyday now and have been for about a week but we did miss one day it was raining. Ill try bumping it up a few days again. Just seemed odd to me from what ive read here to come from 18TC to 4.5 and maintain 4.5 for so long to have algae come back. Thanks for the advice.
 
Yes, fully follow the SLAM process. The "And Maintain" part of that is the key and what most beginners fail to do.
I had to Maintain shock levels in my pool for over 2 MONTHS to clear up my algae problem!! It worked but was slow and frustrating...but it works.
Keep those chlorine levels up!!
 
Agent99 said:
Yes, fully follow the SLAM process. The "And Maintain" part of that is the key and what most beginners fail to do.
I had to Maintain shock levels in my pool for over 2 MONTHS to clear up my algae problem!! It worked but was slow and frustrating...but it works.
Keep those chlorine levels up!!
Click to expand...
That seems very excessive. The entire SLAM process should not take more than about 2 weeks for an absolute swamp. A little algae should be cleared up in a couple days. So, there must have been some mitigating factors if yours took 2 months.
 

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If your CYA is 70, you should keep free chlorine at 6.0 minimum and shoot for 8.0 to be safe. So at 4.5, you're under the minimum...thats why algae is growing.
 
jblizzle said:
That is hardly typical. Almost looks like it was more organic staining than it was live algae. Way to keep after it though :goodjob:
Click to expand...

It was shocking to me. I think I had some seriously tough, Clint Eastwood/John Wayne type of algae! Or maybe the roughness of the Pebble Sheen finish allow the algae to really dig its claws and fight the barrage of chlorine I was hitting it with! I did eventually win! :D
 
Griswald said:
If your CYA is 70, you should keep free chlorine at 6.0 minimum and shoot for 8.0 to be safe. So at 4.5, you're under the minimum...thats why algae is growing.
Click to expand...

OP has a SWG pool, with CYA of 70ppm, FC recommended minimum is 3ppm, with a daily FC target of 5ppm.

The algae is not ‘coming back’, it’s just never been completely eliminated. That will change after a proper SLAM.
 
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