Constant Algae Problems Despite High Chlorine Levels

kbf8

Member
Jul 28, 2021
6
Wilmington, NC
We are new pool owners of a 6,000 gallon above ground pool and we have been plagued by algae problems since the beginning. We have already drained the pool twice because it seems to be the only way to rid ourselves of the algae. We are running the sand filter (1,500 gallon/hr) Sand Filter Pump) 24/7, vacuuming, cleaning out debris, and scrubbing the walls daily. Once we see any signs of algae we begin shocking it with bleach every night to keep FC levels at 10. We have never let the FC numbers go below 5. We test it at least every other day with a Taylor k-2006 pool kit. We have had problems with our Alkalinity levels fluctuating frequently but we try to address it as soon as it goes out of range. We are at our wits end and the local pool store has been zero help. We would welcome any and all advice!
 

V___25

Gold Supporter
May 30, 2020
232
Central PA
Can you post your full tests results? You should be testing and adding chlorine/bleach daily - not just when you see signs of algae. By that point, it's too late. What about your ladder? Have you taken that out and scrubbed it?
 

Bperry

Gold Supporter
Aug 20, 2020
852
Knoxville, TN
We are new pool owners of a 6,000 gallon above ground pool and we have been plagued by algae problems since the beginning. We have already drained the pool twice because it seems to be the only way to rid ourselves of the algae. We are running the sand filter (1,500 gallon/hr) Sand Filter Pump) 24/7, vacuuming, cleaning out debris, and scrubbing the walls daily. Once we see any signs of algae we begin shocking it with bleach every night to keep FC levels at 10. We have never let the FC numbers go below 5. We test it at least every other day with a Taylor k-2006 pool kit. We have had problems with our Alkalinity levels fluctuating frequently but we try to address it as soon as it goes out of range. We are at our wits end and the local pool store has been zero help. We would welcome any and all advice!
If you’ve been trusting the pool store for water testing it would be wise to get your own FAS-DPD kit and test yourself, this site suggests the TF-100 fit that. The bleach needs to go in before the algae shows up.
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,645
Southern OK
Great job on having the K-2006 test kit... You should be testing daily, same time and adding at the same time daily.. we have you and you can do this.. I have been following TFP for 8 years and have never had a green pool so I know it can be done...

Please post your numbers from your K-2006 tonight..

FC:
CC:
PH:
TA:
CYA:

How are you chlorinating your pool? Liquid chlorine or dichlor?

We got you :)
 
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kbf8

Member
Jul 28, 2021
6
Wilmington, NC
Can you post your full tests results? You should be testing and adding chlorine/bleach daily - not just when you see signs of algae. By that point, it's too late. What about your ladder? Have you taken that out and scrubbed it?
We have been trying to keep a constant FC level of at least 5 PPM, so yes, we do add chlorine every day. It is once we start seeing signs of algae that we up it to 10 PPM. Yes, we have been scrubbing the ladder. Current numbers are:
FC 3
CC .5
PH 7.5
TA 120
CH 190
CYA 30
 

kbf8

Member
Jul 28, 2021
6
Wilmington, NC
If you’ve been trusting the pool store for water testing it would be wise to get your own FAS-DPD kit and test yourself, this site suggests the TF-100 fit that. The bleach needs to go in before the algae shows up.
Yes, we have a Taylor test kit and we do add chlorine everyday. We try to keep a constant FC level of 5 and once we see any sign of algae we up it to 10.
 

kbf8

Member
Jul 28, 2021
6
Wilmington, NC
Great job on having the K-2006 test kit... You should be testing daily, same time and adding at the same time daily.. we have you and you can do this.. I have been following TFP for 8 years and have never had a green pool so I know it can be done...

Please post your numbers from your K-2006 tonight..

FC:
CC:
PH:
TA:
CYA:

How are you chlorinating your pool? Liquid chlorine or dichlor?

We got you :)
Thank you! We didn't know you should be testing and adding at the same day each day. We will definitely start doing that. We are using liquid chlorine. I just tested the water now and the results were:
FC: 3
CC: 0.5
PH: 7.5
TA: 120
CYA: 30
 

Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
10,782
NY
Hey KB !!!
. Yes, we have been scrubbing the ladder.
ok GREAT !!! They are notorious for poor circulation and introducing algae for unsuspecting folks. With properly sanitized water there isn’t much else to go wrong for the above grounders without rock walls, waterfalls and whatnot


3 thoughts. What shape is your filter in and how long has it been since it was deep cleaned ? Backwashing is great for quick fixings but if something is rooted deep in the sand you’ll be reintroducing it and spinning your wheels.

Also, are you making sure to mix well when it rains ? Cold 0 FC rain water will sit on top and fester for up to 16 hours if the pump isn’t going to be on for a while. Rain will only lower your levels by 1-2% and be unnoticeable *if* it’s properly mixed.

lastly, all above ground pools have shade all day in different parts of the walls. They need to be swam in frequently, or either brushed or mixed with the pump frequently or Algae will grow on the walls.

*edit for your post above which came in while I’m typing. Expect to lose 2-4 ppm daily to normal UV / bather load. The pool needs to be checked daily until you become one with it.
 
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cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,645
Southern OK
Perfect :)

So now you are close to a SLAM Process

Take your FC to 12 and then test every 2 hours... adding chlorine back to 12 FC.. the green will go away..

In your fist post you said you are testing about every 2 days, that is probably why this is happening.. Once you FC drops below the minimum Algae starts growing... If your FC is 5 on day 1, then drops 3 fc to 2 you are at the minimum.. then the next day you are at 0 or 1 FC.. once you are below that min your water is going green...

FC/CYA Chart
 
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kbf8

Member
Jul 28, 2021
6
Wilmington, NC
Hey KB !!!

ok GREAT !!! They are notorious for poor circulation and introducing algae for unsuspecting folks. With properly sanitized water there isn’t much else to go wrong for the above grounders without rock walls, waterfalls and whatnot


3 thoughts. What shape is your filter in and how long has it been since it was deep cleaned ? Backwashing is great for quick fixings but if something is rooted deep in the sand you’ll be reintroducing it and spinning your wheels.

Also, are you making sure to mix well when it rains ? Cold 0 FC rain water will sit on top and fester for up to 16 hours if the pump isn’t going to be on for a while. Rain will only lower your levels by 1-2% and be unnoticeable *if* it’s properly mixed.

lastly, all above ground pools have shade all day in different parts of the walls. They need to be swam in frequently, or either brushed or mixed with the pump frequently or Algae will grow on the walls.

*edit for your post above which came in while I’m typing. Expect to lose 2-4 ppm daily to normal UV / bather load. The pool needs to be checked daily until you become one with it.
Thank you! That's some great advice. We've never thought to mix the water after a rain.

I do wonder about our filter. It's a sand filter that came with the pool. We set it up brand new back in April and backwash it every couple days. Even running it 24/7 it doesn't seem to be doing anything. We have noticed that when we vacuum up the algae from the bottom of the pool we can see the some of it coming out of the outtake valve as we vacuum. Is that normal?
 

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kbf8

Member
Jul 28, 2021
6
Wilmington, NC
Perfect :)

So now you are close to a SLAM Process

Take your FC to 12 and then test every 2 hours... adding chlorine back to 12 FC.. the green will go away..

In your fist post you said you are testing about every 2 days, that is probably why this is happening.. Once you FC drops below the minimum Algae starts growing... If your FC is 5 on day 1, then drops 3 fc to 2 you are at the minimum.. then the next day you are at 0 or 1 FC.. once you are below that min your water is going green...

FC/CYA Chart
We'll give that a try. The thought of keeping it at 5 ppm was so that it wouldn't drop too low but looking at the chart it looks like 5 is closer to the minimum range. Is it safe to swim in when the FC is above 5?
 
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Bperry

Gold Supporter
Aug 20, 2020
852
Knoxville, TN
Thank you! That's some great advice. We've never thought to mix the water after a rain.

I do wonder about our filter. It's a sand filter that came with the pool. We set it up brand new back in April and backwash it every couple days. Even running it 24/7 it doesn't seem to be doing anything. We have noticed that when we vacuum up the algae from the bottom of the pool we can see the some of it coming out of the outtake valve as we vacuum. Is that normal?
You don’t need to backwash it unless the pressure rises ~25% over its normal clean pressure. Some even say it filters better if it’s a little dirty.
 

Bperry

Gold Supporter
Aug 20, 2020
852
Knoxville, TN
We'll give that a try. The thought of keeping it at 5 ppm was so that it wouldn't drop too low but looking at the chart it looks like 5 is closer to the minimum range. Is it safe to swim in when the FC is above 5?
If you follow the FC/CYA chart it’s safe to swim in anything at or below SLAM level.
 
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