Just can't get rid of the algae

[Snowshoe]

I’ve had an algae issue for quite some time now. I’ve never had green water but algae will form on the bottom of the pool. It is not growing on the bottom but I believe it is growing in the water and eventually settles on the bottom. If you stir up the water, say by waving a skimmer net just above the bottom, the algae will also stir up with the water (i.e. it is not stuck to the bottom). It will also grow on certain sides of the pool if I don’t brush it 2-3 times/week.

I did a SLAM this summer which took about a week and I performed it by the book and ended when there was no sign of the algae, CC was 0 and OCLT was 0. In about 3-4 weeks the algae was back again.

I assumed I somehow did not keep the SLAM going long enough so I performed a 2 week SLAM which I kept up for about a week past where the 3 tests indicated I was good to stop. I also kept the FC levels elevated for several weeks after the SLAM – nominal FC is 5-7 (CYA 40) and I have kept the FC between 9-11 post-SLAM. The algae returned again about 3 weeks after I ended the SLAM even though the FC never went below 9.

The caveat is that my phosphates were above 4000 ppb. I know, I know, I know, the consensus is that they don’t matter but I am getting very tired and frustrated by this. I do not have the Taylor phosphate test kit and the pool store test maxes out at 4000 so I didn’t know how much above 4000 they were. I know the opinions about pool store testing but I took a sample to another store and got the same results. I also have just ordered the Taylor K-1106 kit.

After this last SLAM I treated with Orenda PR-10000. The water got cloudy but not very cloudy and I got the white junk on the bottom. After that the pool store tested the phosphates at around 3600 ppb. There’s obviously something wrong here but I can’t come up with anything other than the high phosphates are feeding the algae even though all the talk I’ve seen on this site say maintain the FC level and the phosphates don't matter.

 

[Donldson]

I do not have the Taylor test kit

Your signature indicates you have a Taylor k-2006. Are you saying that you are relying on the pool store for all of your testing and your signature is not up to date, or are you just saying that you do not have your own phosphate test kit?

 

[HermanTX]

What you did to address phosphates with Orenda PR-10000 is fine. I have done the same (but I did not have any algae-did it for preventive measure). Since you have the Orenda, I would do another dose to get below 500ppb if you can. You may want to do it in stages. Waiting until you get the proper test kit is best to confirm your actual level of phosphates. EDIT - wait until the pool is free of algae to test and treat for phosphates.
The test is a little tricky as there are 2 different methods depending if you have phosphate under 1000 ppb or over 1000 ppb. Just follow the instructions.

Do you have a cover? A ladder? Pool toys? All of these can hold algae and bring it back in the pool if exposed.
What you did on SLAM sounds right and you were holding FC at high end of target range post SLAM which is also good.
So it may be there is some hidden algae. Also, have you looked behind the lights?

 

[Mdragger88]

The pool needs to be algae free before treating for phosphates.

Phosphate Removers - Further Reading

www.troublefreepool.com

 

[JamesW]

Algae is super simple.

If you get algae, you are not maintaining the fc high enough.

Maybe you have mustard algae, which is harder to kill and keep it from reoccurring, but the same principle applies.

 

[Bperry]

I do not have the Taylor test kit and the pool store test maxes out at 4000 so I didn’t know how much above 4000 they were.

You can’t do a SLAM without the test kit. It’s just one of those things.

Please please please stop using a pool store for testing!

 

[mgtfp]

I think Snowshoe is referring to not having the Taylor Phosphate test. Taylor K2006 is listed in the signature.

With or without phosphates, you'll need to keep slamming. And keep brushing, even after the Slam. And make sure you go through all the hiding spots for algae, like light niches, behind the skimmer weir door, pool ladders, etc.

 

[PoolGate]

Do you log your testing? I see your logs are shared but have no data in them. But, as stated above, the answer is always, "use more chlorine".

 

[Snowshoe]

Your signature indicates you have a Taylor k-2006. Are you saying that you are relying on the pool store for all of your testing and your signature is not up to date, or are you just saying that you do not have your own phosphate test kit?

Sorry I was not clear. I do have the Taylor K-2006 kit which I use to do all my testing other than phosphates but just ordered the K-1106.

 

[Snowshoe]

Algae is super simple.

If you get algae, you are not maintaining the fc high enough.

Maybe you have mustard algae, which is harder to kill and keep it from reoccurring, but the same principle applies.

If it was that simple I would not have it. As I clearly stated in my post my FC level has been maintained significantly above nominal levels.

 

[Snowshoe]

The pool needs to be algae free before treating for phosphates.

Phosphate Removers - Further Reading

www.troublefreepool.com

I am aware of that.

 

[Snowshoe]

You can’t do a SLAM without the test kit. It’s just one of those things.

Please please please stop using a pool store for testing!

I was not clear in my original post. I have the K-2006. What I meant was I did not have the phosphate test kit.

 

[JamesW]

If it was that simple I would not have it.

If you have algae, the FC is not being maintained.

That is how it works.

People periodically think that they have a special case where sufficient FC does not prevent algae.

There are no special cases.

Algae is killed by the correct level of chlorine, period.

 

[Mdragger88]

On this round of slamming be sure to search for hidden sources of algae -
*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
If you suspect Mustard algae you should also do those protocols after completing the SLAM Process. Being sure to maintain mustard algae minimum for some time thereafter as listed on the o.g. Chart.

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.google.com

After all that, Then proceed with your phosphate removal.
Do you have any water features that you aren’t running very frequently that may be the source of the reoccurrence? If so be sure to run them a couple hours a day during slam & at least 30 minutes or so each day normally.

 

[PoolGate]

Doesn't phosphate remover react with chlorine to reduce the chlorine effectiveness? If you are following pool store advice and buying phosphate remover perhaps that caused your chlorine to drop. Are you using phosphate remover?

 

[Snowshoe]

What you did to address phosphates with Orenda PR-10000 is fine. I have done the same (but I did not have any algae-did it for preventive measure). Since you have the Orenda, I would do another dose to get below 500ppb if you can. You may want to do it in stages. Waiting until you get the proper test kit is best to confirm your actual level of phosphates.
The test is a little tricky as there are 2 different methods depending if you have phosphate under 1000 ppb or over 1000 ppb. Just follow the instructions.

Do you have a cover? A ladder? Pool toys? All of these can hold algae and bring it back in the pool if exposed.
What you did on SLAM sounds right and you were holding FC at high end of target range post SLAM which is also good.
So it may be there is some hidden algae. Also, have you looked behind the lights?

These are all good points. the only thing I have is a pool sweep, solar cover and one light. No ladder, no toys. I scrubbed the pool sweep the best I could with a chlorine solution. Maybe it's coming back from the solar cover but I'm just very surprised that it would come back when the FC level has been above 9 ppm. I'm not sure what you mean by "behind the lights". I've never really looked at how to take it apart.

 

[PoolGate]

Honestly I am not entirely sure what you are fighting is algae. Can you post a picture of it?

 

[Snowshoe]

On this round of slamming be sure to search for hidden sources of algae -
*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
If you suspect Mustard algae you should also do those protocols after completing the SLAM Process. Being sure to maintain mustard algae minimum for some time thereafter as listed on the o.g. Chart.

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.google.com

After all that, Then proceed with your phosphate removal.
Do you have any water features that you aren’t running very frequently that may be the source of the reoccurrence? If so be sure to run them a couple hours a day during slam & at least 30 minutes or so each day normally.

See my reply to HermanTx. There's not a lot of nooks and crannies in the pool but I will keep this in mind. Also a good point about mustard algae. I didn't think so as it appears more green than yellow although I read one article that said it is a form of green algae. I'm starting to think may be likely since it is returning even with FC levels at 9 ppm and higher.

Doesn't phosphate remover react with chlorine to reduce the chlorine effectiveness? If you are following pool store advice and buying phosphate remover perhaps that caused your chlorine to drop. Are you using phosphate remover?

On this round of slamming be sure to search for hidden sources of algae -
*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
If you suspect Mustard algae you should also do those protocols after completing the SLAM Process. Being sure to maintain mustard algae minimum for some time thereafter as listed on the o.g. Chart.

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.google.com

After all that, Then proceed with your phosphate removal.
Do you have any water features that you aren’t running very frequently that may be the source of the reoccurrence? If so be sure to run them a couple hours a day during slam & at least 30 minutes or so each day normally.

 

[Snowshoe]

Doesn't phosphate remover react with chlorine to reduce the chlorine effectiveness? If you are following pool store advice and buying phosphate remover perhaps that caused your chlorine to drop. Are you using phosphate remover?

As I said in my original post, I did one treatment with Orenda PR-10000 after the last SLAM. I have not read anything that indicated it would reduce chlorine effectiveness.

 

[JJ_Tex]

If it was that simple I would not have it. As I clearly stated in my post my FC level has been maintained significantly above nominal levels.

I've seen several people post similar sentiments. Many times they go down rabbit holes trying to figure it out and drive themselves crazy, but I always try to remind them to keep it simple. If you have algae, the chlorine is too low and needs to be higher. Its truly as simple as that.

It could be a million different reasons as to why. Maybe you have hidden algae, maybe you're testing incorrectly, maybe your pool has areas of bad circulations, maybe you get more debris in your pool and need more chlorine than the target range, maybe you don't really have algae, maybe aliens come and poop in your pool at night, etc.

Just keep it simple and know that your current FC levels isn't working. I would do 3 things:
1. Do an OCLT to confirm that you truly have algae
2. Assuming you fail the OCLT, restart the SLAM and double/triple check before you end the SLAM
3. Post SLAM, keep your chlorine higher than you have been even if that is higher than the published targets. As long as its below SLAM its safe to swim. Heck, just take a peek at my avatar and you can see my chlorine is way higher than the target range. I like to know that my pool can handle anything the backyard throws at it.