Controlling Green Algae

shaposhalex

Member
Dec 27, 2020
12
Sugar Land, TX
Dear TFP community,

I am a fairly new user of TFP as well as a new pool owner (since October 2020). That being said, I managed keeping up with testing the water and managing to keep the pool clean throughout winter in Houston, TX by maintaining a balance of PH/TA/FC/CC/CYA etc.

I have more of a check question as to whether it is normal algae growth or excessive. My pool is balanced now and has been balanced for weeks with a normal maintenance routine. I notice that the walls on the pool start turning green daily during the sunlight with balanced water, and I find myself scrubbing the pool walls and stairs facing the sun daily, as if I don't scrub they turn green.

I just did a quick daily test using Taylor K-1000. Total Chlorine 3 and PH 7.5.

Thanks for any feedback or suggestions of preventing walls turning green like everyday!
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
39,395
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
A FC of 3 at any CYA is the minimum level. So you are likely going below that, often. What is your CYA?
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
16,567
Evans, Georgia
FIrst off, most of us only use that OTO kit to check for the "presence" of chlrine but not a specific number...and the pH.

If you've got algae your FC is NOT high enough. Are you following the CYA/FC chart?? FC/CYA Chart

Can you give me current test results??
FC
CC
pH
TA
CH
CYA
Salt if applicable

Maddie :flower:
 

shaposhalex

Member
Dec 27, 2020
12
Sugar Land, TX
Thank you all for fast responses. Maddie, I think you are right on the point. I really failed to keep inline with that chart. Per that chart, comparing to liquid chlorine, I need a minimum of 4 FC and target is 6-8 FC.

The following are measurements using TF-100

FC - 3
CC - 0
pH - 7.5
TA - 80
CH - 320
CYA - 50
Not a salt pool


Is it ok to keep FC at 6-8? I thought FC needs to be within 5ppm to be safe for swimming, or does that really depend on the CYA? That video and FC/CYA Chart makes it seem that it is My CYA is growing, and unfortunately I am not using liquid chlorine on a daily basis, and only using it for SLAM process.

When we bought the house with the pool (Oct 2020) and prior to finding TFP, I ordered 50 lbs bucket of pucks and 50 lbs bucket of Zappit 73% Cal Hypo.
I use the pucks in the automatic chlorinator, adding 4-5 at a time and keeping the automatic chlorinator setting on 5-max. When I test daily with K-1000 and see my total chlorine level falling below 2ppm, I add some Zappit to bring the chlorine level back up.

Thank you all, Alex
 
Last edited:

shaposhalex

Member
Dec 27, 2020
12
Sugar Land, TX
Are you using pucks? Or liquid chlorine ??
Thank you all for fast responses. Maddie, I think you are right on the point. I really failed to keep inline with that chart. Per that chart, comparing to liquid chlorine, I need a minimum of 4 FC and target is 6-8 FC.

The following are measurements using TF-100

FC - 3
CC - 0
pH - 7.5
TA - 80
CH - 320
CYA - 50
Not a salt pool


Is it ok to keep FC at 6-8? I thought FC needs to be within 5ppm to be safe for swimming, or does that really depend on the CYA? That video and FC/CYA Chart makes it seem that it is My CYA is growing, and unfortunately I am not using liquid chlorine on a daily basis, and only using it for SLAM process.

When we bought the house with the pool (Oct 2020) and prior to finding TFP, I ordered 50 lbs bucket of pucks and 50 lbs bucket of Zappit 73% Cal Hypo.
I use the pucks in the automatic chlorinator, adding 4-5 at a time and keeping the automatic chlorinator setting on 5-max. When I test daily with K-1000 and see my total chlorine level falling below 2ppm, I add some Zappit to bring the chlorine level back up.

Thank you all, Alex
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
16,567
Evans, Georgia
That is the job of the CYA.... you can swim safely at 6,7 or 8ppm because the CYA buffers the chlorine.
ZERO CYA and 1ppm of FC, *that* would be far, far harsher.

IF you continue using pucks your CYA is going to get far too high to balance against the FC. Its bad practice.

Maddie :flower:
 

shaposhalex

Member
Dec 27, 2020
12
Sugar Land, TX
That is the job of the CYA.... you can swim safely at 6,7 or 8ppm because the CYA buffers the chlorine.
ZERO CYA and 1ppm of FC, *that* would be far, far harsher.

IF you continue using pucks your CYA is going to get far too high to balance against the FC. Its bad practice.

Maddie :flower:
Maddie,

Thank you so much for your explanations, and that makes sense. I went ahead and performed SLAM using Cal Hypo and maintain FC above 20ppm now, and it does work, added some more Cal Hypo today and it works....no green algae starts to build up on the walls of the pool.

I retested CYA and I am going up, already at about 60 (probably from the tablets I had in automatic chlorinator), as I thought Cal Hypo from Zappit does not have CYA. As the CYA is increasing, FC needs to keep increasing and I see that pucks are a bad practice. I guess I need to start draining the pool half way and refilling periodically, to start getting CYA back closer to 30ppm, if using pucks. I have not drained the pool at all since we purchased the house in Oct 2020, and just maintained the chemistry balance and added a little water due to evaporation.....hence build up of CYA

Couple of questions:
1) Do you and most people on TFP use liquid chlorine instead of pucks to keep chlorinating the pool
2) This is where the investment into SWCG may be worth it. I heard it is a lot less pain with SWCG, although the salt is causing the pipes to become rusty. Not sure it is a problem though for me, considering the pipes are PVC. Is Salt water pool trully a better investment and less maintenance?
To keep up with my 20K gallon pool, without using pucks, I will need a lot of boxes of liquid chlorine for the hot Texas summer that is coming up (will literally need a truckload of liquid chlorine), alternatively, I suppose I could continue using the pucks, and drain the water periodically - which is also not ideal considering water is a scarce resource.

This is such a great site and forum. Thank you, and I am so happy I became a user of the site. Way better than to constantly be cheated by the pool stores/and service guys.

Thank you for the inputs. Alex
 

Oly

Gold Supporter
Jun 28, 2017
2,023
Fresno, CA
Pool Size
27000
Hi Alex,
Yes most pool owners on TFP primarily use liquid chlorine or a SWCG. You can, and many pool owners who hire a service do use solid forms of chlorine but you must understand how they will affect your water chemistry or you risk having to drain and refill your pool eventually or do battle with algae and the nightmares of magic pool store potions that drain your wallet first then your pool water next.
I just installed a SWCG and did not have to add any salt for it to work. In fact I had to drain and refill about 18" of water because my salt levels were too high due to using liquid chlorine which also contains salt (sodium chloride) for the last 3 1/2 years. A good test kit puts you in charge and all the good people here will be happy to guide you to a Trouble Free Pool experience. :cheers:
 
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jimbethesda

Gold Supporter
Jul 2, 2018
510
Austin, TX
The experts have already chimed in, but I wanted to add one thing.

You said “I have more of a check question as to whether it is normal algae growth or excessive”.

To be clear, there is no normal algae growth. Those that test regularly and follow TFP parameters don’t get any algae. I never have. I spend maybe 20 mins a week on my pool.
 

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YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
16,567
Evans, Georgia
Yes, most TFPers use either Liquid Chlorine (LC) or the SWG. I have a SWG. In almost 10 years I've never had algae. Its all a matter of keeping track of your FC level based on your CYA. FC/CYA Chart
My first cell for the SWG lasted almost 9 years. What you pay for the SWG is just about the same as you'd pay for all the LC you need- its just that you're paying for it upfront.
For your size pool you would want a SWG that works for 40,000 gallons. We always suggest 2x the pool's volume for a cell so you can run it fewer hours to make it last longer.

Maddie :flower:
 

iflyjetzzz

Well-known member
Jun 16, 2011
108
Las Vegas, NV
Alex, it's already been mentioned that the pucks are raising your CYA.
In addition, that CalHypo is raising your CH. Get it too high and you'll start getting a calcium ring form around your pool's waterline.

So you're getting two longer term problems - high CYA and high CH. The only way to lower those two are with a partial pool drain and refill.
I had those same issues as you (high CYA and CH) in a pool at a previous house. I read a great solution on this forum when I did partial drains ... use the water you drain from the pool to water the plants and lawn. That's what I did.
Your current CYA and CH aren't bad, but if you continue using pucks and CalHypo, your CYA and CH levels will be high at the end of the summer. If you want to use up your pucks and CalHypo, you can do so this summer as long as you plan on doing a partial pool drain this fall (I did partial drain/refills when my water usage was low because our water is priced at different tiers depending on usage ... higher usage pays higher prices).

But right now, your problem is algae. Since you SLAM'd the pool, that should have fixed your algae issues. Do you know what your phosphate level is? If it's high, consider using an inexpensive effective phosphate remover such as SeaKlear or Orenda. I use SeaKlear PhosKlear 4000; very cheap, effective, and easy to use. By reducing/eliminating phosphates, you're getting rid of algae food just in case your chlorine level falls too low again. And SeaKlear and Orenda are cheaper than SLAMing ... there are other phosphate removers that are expensive and definitely not worth the extra money since both SeaKlear and Orenda work very well at a great price.
 

mguzzy

Gold Supporter
I have more of a check question as to whether it is normal algae growth or excessive. My pool is balanced now and has been balanced for weeks with a normal maintenance routine. I notice that the walls on the pool start turning green daily during the sunlight with balanced water, and I find myself scrubbing the pool walls and stairs facing the sun daily, as if I don't scrub they turn green.
I'll reiterate what others have already said... Any algae is excessive. You shouldn't have to be scrubbing the walls. That just tells us you are on the verge of a bloom.. So good job you saw that and SLAMed. I would start using Liquid Chlorine. You can keep the pucks but use them in the winter when you get enough rainfall to dilute the effects of the CYA or CH. good luck!
 

shaposhalex

Member
Dec 27, 2020
12
Sugar Land, TX
Wow, such a wealth of information.....Thank you so much folks! @jimbethesda I like " I spend maybe 20 mins a week on my pool." That tells me I am doing something incorrect, as I spend more than that every day to clean, and running vacuum to keep clearing that algae constantly.

Do you guys buy LC from hardware store, or is there a great place to order it in bulk online and get it shipped your way?

 
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JJ_Tex

Gold Supporter
Bronze Supporter
Jul 17, 2019
2,353
Prosper, TX (DFW)
Pool Size
13000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Walmart is usually the best place to get it, in their pool section called Pool Essentials Chlorinating Liquid. Home Depot, Lowes, etc. should all carry it. I've seen Houston area members talk about a place to get it in bulk in Spring, but that is a bit of a hike for you.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
39,395
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Do you know what your phosphate level is? If it's high, consider using an inexpensive effective phosphate remover such as SeaKlear or Orenda. I use SeaKlear PhosKlear 4000; very cheap, effective, and easy to use. By reducing/eliminating phosphates, you're getting rid of algae food just in case your chlorine level falls too low again. And SeaKlear and Orenda are cheaper than SLAMing ... there are other phosphate removers that are expensive and definitely not worth the extra money since both SeaKlear and Orenda work very well at a great price.
Just to be clear, being concerned about phosphates is not relevant to TFPC. Keeping your pool clear of algae makes the phosphate level of no concern. And unless you have your own quality phosphate test kit, you have no idea what the phosphate level is in your pool water.
 
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iflyjetzzz

Well-known member
Jun 16, 2011
108
Las Vegas, NV
There's no need to test phosphates. Just add a couple of ounces of SeaKlear or Orenda a couple of times a year when you're going to clean the pool filter. Once the phosphates come out in solution, just vacuum them up and clean the pool filter. It's a very cheap and simple process; easier than having to clean up an algae bloom.
You'll know from the amount of phosphates removed whether or not your phosphate level was high.
And with many equipment manufacturers specifying a maximum amount of phosphates in the water, one is at risk of voiding your equipment warranty. Another poster here had written about that specific problem (manufacturer voiding the warranty) when his SWG stopped working.
Another direct benefit of lowering/removing phosphates is that your pool's chlorine demand will decrease, making pool maintenance easier.
 

mguzzy

Gold Supporter
There's no need to test phosphates. Just add a couple of ounces of SeaKlear or Orenda a couple of times a year when you're going to clean the pool filter.
If you are going to dump something in your pool you should test for it, so you know what it is doing to your water. ...

Never mind that if you follow the TFP protocol in its strictest sense, their is no need to control phosphates. Phosphates and Nitrates are limiting nutrients, so all you are doing is reducing the algae food. It doesn't kill the algae.
 
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