Algae on pool walls; SLAM worthy?

Zools

0
Aug 9, 2016
8
DFW, TX
For probably about 2 months our pool has been growing green algae along the walls under the waterline and in the grout of our tile. The water is clear. This is the 2nd summer we've had the pool and had no issues the first year.

As an initial attempt to solve the issue I had been brushing it weekly and increased FC by turning up the inline dispenser. I also did a simple shock once that had no effect. Several days after bushing the algae continues to return. Additionally, i'm having trouble keeping the FC very high with the inline dispenser.

After coming here for more and better information along with running all necessary tests, here are my tests and plan

FC: 2.0
PH: 7.4
TA: 80
CH: 340
CYA: 70-90 (the range is because had some issues thinking I was still seeing the dot)
CC: 0 (it was maybe a very faint bit of pink but has to be very close to 0)

I want to SLAM the pool but because of the high CYA I believe I need to solve that problem first. Since, our CH is very high as well I was thinking of draining the pool half way and filling with fresh water to lower the CYA and CH before beginning. After I get those lowered I will do a SLAM.

Does this plan seem viable?
 
For probably about 2 months our pool has been growing green algae along the walls under the waterline and in the grout of our tile. The water is clear. This is the 2nd summer we've had the pool and had no issues the first year.

As an initial attempt to solve the issue I had been brushing it weekly and increased FC by turning up the inline dispenser. I also did a simple shock once that had no effect. Several days after bushing the algae continues to return. Additionally, i'm having trouble keeping the FC very high with the inline dispenser.

After coming here for more and better information along with running all necessary tests, here are my tests and plan

FC: 2.0
PH: 7.4
TA: 80
CH: 340
CYA: 70-90 (the range is because had some issues thinking I was still seeing the dot)
CC: 0 (it was maybe a very faint bit of pink but has to be very close to 0)

I want to SLAM the pool but because of the high CYA I believe I need to solve that problem first. Since, our CH is very high as well I was thinking of draining the pool half way and filling with fresh water to lower the CYA and CH before beginning. After I get those lowered I will do a SLAM.

Does this plan seem viable?

Welcome!

It does, especially if your fill water has lower CH. It sounds like algae is winning there which explains your high FC loss. It also sounds you're using solid chlorine for chlorinating and it causes your CYA rise as you probably already know. Please note SLAM is multi- day process and you'll need your pump/filter running 24/7 during that period. If your pump is VS type you can run it at lower speed, as long as it provides good circulation.
 
Welcome!

It does, especially if your fill water has lower CH. It sounds like algae is winning there which explains your high FC loss. It also sounds you're using solid chlorine for chlorinating and it causes your CYA rise as you probably already know. Please note SLAM is multi- day process and you'll need your pump/filter running 24/7 during that period. If your pump is VS type you can run it at lower speed, as long as it provides good circulation.

Thanks for the feedback. Yeah, I do use solid chlorine and realize it increases CYA over time. Are there liquid dosing alternatives? I live in Texas which obvoiusly gets a lot of sun, I know that without something that is automatically dosing, I wouldn't be able to keep up with the chlorine levels.

Will be sure to run the pumps non stop, unfortunately our pump isn't VS so we'll just have to eat the power bill.
 
Welcome to TFP!

Yes, there are liquid chlorine dosers. Two most common here are the Stenner pump and the Liquidator. Lots of folks here use them. More common is a saltwater chlorine generator. With CYA in the 80ish ppm range your FC loss should be 2-4 ppm per day. That is 45-90 oz of 8.25% bleach per day or 38-77 oz of 10% liquid chlorine per day.

Add TX to your location over there <--- so folks can know your climate when trying to help you with your pool.
 
You need to stop using pucks and start using liquid chlorine (aka "bleach") as it adds nothing else to your water to worry about. You didn't have your FC high enough to compete with the high CYA you were running. So a partial drain would be useful before you SLAM the pool.

Directions to SLAM-> SLAM Process

Your CH is not too high for a plaster pool. Its just on the higher end for a non-SWG pool. Pool School - Recommended Levels
 
Hold the phone!! I just saw you have a UV sterilizer (well, sort of). Is that why your FC is so low?

UVs are worthless, especially in Texas where you get *plenty* of free UV sunlight. If you're keeping your FC low thinking that its going to pick up the slack you are sadly mistaken. I'm sorry.

I would ignore that equipment or disconnect it and continue on using chlorine only.
 
Hold the phone!! I just saw you have a UV sterilizer (well, sort of). Is that why your FC is so low?

UVs are worthless, especially in Texas where you get *plenty* of free UV sunlight. If you're keeping your FC low thinking that its going to pick up the slack you are sadly mistaken. I'm sorry.

I would ignore that equipment or disconnect it and continue on using chlorine only.

I'm not intentionally keeping the FC low because of the sterilizer. I understand the sterilizer is mostly worthless and will likely be removing it. It was installed with our pool before I knew enough about pool equipment and chemistry.
 

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