Controlling Algae in an Environment with Perfect Chemical Balance - Phosphates?

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Seadweller

Well-known member
Aug 21, 2009
232
Tampa Bay Area
I've been testing my pool water for months and have maintained what I consider a nearly "perfect" chemical balance. I was keeping my FC at 5 to 6, which is well above the level called for in the Pool Calculator, yet I continued to get a dusting of algae in my pool. After hearing from a fellow Floridian with a similar issue, I raised my FC to between 8 and 10. To my surprise, I continue to get a dusting of algae every 3 to 4 days, in the form of light spots on the walls and floor of the pool at random locations. The water is crystal clear, and I don't believe it should be necessary to brush the pool every day to keep algae at bay.

I can physically feel the circulation of the pool water, so I don't have a "dead spot" issue or lack of circulation, which was my last option to consider as to why I keep getting algae. I've increased pump run times and speeds, increased the output and run time of my salt system, etc., to no avail. I won't get into the gory details, but trust me, I'm running everything much longer than should be required, and keeping FC higher than should be needed to boot. Then I thought, is there a chlorine resistant algae I'm dealing with? I slammed the pool twice, both times passing the OCLT test with flying colors. The second time, I passed the OCLT test twice, yet the algae returns. I can still pass an OCLT test, and typically have a CC of 0.

Intrigued? I am, and no, I'm not going to post my test results, because I don't want to go down the path of discussing chemical balance. I've got that covered in spades! ;)

I know the topic of phosphates seems taboo here on TFP, but I'm beginning to think there may be some merit to opening a discussion about this, as I've exhausted every other avenue. Algae should not present with a maintenance level FC of 8, so something is going on in my pool, and perhaps hundreds of other pools. Has anyone noticed a dramatic increase in "can't get algae out of my pool" posts?

Something beyond the basics is happening, at least in my case, and I'd really like to explore a remedy.

Thoughts?
 
Seadweller said:
I've been testing my pool water for months and have maintained what I consider a nearly "perfect" chemical balance. I was keeping my FC at 5 to 6, which is well above the level called for in the Pool Calculator, yet I continued to get a dusting of algae in my pool. After hearing from a fellow Floridian with a similar issue, I raised my FC to between 8 and 10. To my surprise, I continue to get a dusting of algae every 3 to 4 days, in the form of light spots on the walls and floor of the pool at random locations. The water is crystal clear, and I don't believe it should be necessary to brush the pool every day to keep algae at bay.

I can physically feel the circulation of the pool water, so I don't have a "dead spot" issue or lack of circulation, which was my last option to consider as to why I keep getting algae. I've increased pump run times and speeds, increased the output and run time of my salt system, etc., to no avail. I won't get into the gory details, but trust me, I'm running everything much longer than should be required, and keeping FC higher than should be needed to boot. Then I thought, is there a chlorine resistant algae I'm dealing with? I slammed the pool twice, both times passing the OCLT test with flying colors. The second time, I passed the OCLT test twice, yet the algae returns. I can still pass an OCLT test, and typically have a CC of 0.

Intrigued? I am, and no, I'm not going to post my test results, because I don't want to go down the path of discussing chemical balance. I've got that covered in spades! ;)

I know the topic of phosphates seems taboo here on TFP, but I'm beginning to think there may be some merit to opening a discussion about this, as I've exhausted every other avenue. Algae should not present with a maintenance level FC of 8, so something is going on in my pool, and perhaps hundreds of other pools. Has anyone noticed a dramatic increase in "can't get algae out of my pool" posts?

Something beyond the basics is happening, at least in my case, and I'd really like to explore a remedy.

Thoughts?
Click to expand...

Your posted FC levels are meaningless without knowing a CYA level.

I would ask you to post your CYA level, but you have already made it clear that you are not willing to share test results .....
 
Sead,

I'm pretty sure you don't need our permission to do whatever you want with your pool.

I suggest that you knock yourself out and get rid on the Phosphates and see what happens. I believe that our typical answer to the Phosphate question is the "They do not matter".. So worst case, you will not see any improvement in your situation. And maybe in your case it might help... Who really knows for sure.???

If you do use a Phosphate remover, make sure you use a commercial one, not cheap PhosFree stuff. Try Orenda PR-10000 or Halosource SeaKlear..

Keep good records and report back to us with your results.

My personal opinion is that you have never really gotten rid of the algae even when you think the SLAM is completed. So the SLAM knocks the algae back to where it is no longer visible, but it is still there.. Maybe your CYA is much higher than you think it is and have been targeting too low of a "Shock" Level... But again, who knows for sure???

Good luck with your test project...

Jim R.
 
Intrigued? I am, and no, I'm not going to post my test results, because I don't want to go down the path of discussing chemical balance. I've got that covered in spades!
Click to expand...

Seadweller:

Thank you for sharing your test results. Any and all test results are used as a guide to determine how to correct/modify/improve a current or potential problem. We do not discuss chemical balance as there are no set, fast hardened rules. Pools can operate with a vast range of levels, especially CH, TA, PH, and even CYA/FC. So, there is no correct answer.

Are you 100% certain that what you are seeing is algae, and also is this the time that the filter has been off for a few hours? Quite honestly you could have "dead spots" in a pool, no matter what type of set up you have. Where exactly is all this algae? Is it all over the pool walls, or in just certain spots? Maybe uploading some pictures would be helpful.

- - - Updated - - -

1 is on a sod farm.
Click to expand...

Nothing like a "green sod farm". Perfect time for seeding with the cooler nights!
 
How does this algae behave when hit with a brush? How does the area feel to your hand? If you wipe it with a white cloth what do you end up with? Agree pictures would be helpful. Also, you say that testing was done this morning. When does your pump run and your SWG compared to when you are testing? It may be possible that there are times when your SWG is off that your FC is falling below minimum and you aren't even realizing it.
 
Seadweller said:
I'm going to get the phosphate level tested today as I have to get some salt at the pool store (gasp).
Click to expand...

Brace yourself! Another pool store testing rant

I bought a phosphate test kit. Even at Pool $tore prices, it was only $12. It was well worth it. I first didn't heed the directions of testing in daylight, but once I did, the results have been consistent.
 

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If you don't know what your phosphate level is, how can you possibly ask if reducing that level will help?

It's this kind of "leap before you look" topic that gives credence to those who feel that phosphates are just a boogeyman people chase when they can't fix their circulation issues. You have already decided that phosphates are the problem (maybe?), that there is some unexplained increase in algae problems this year (there aren't), and that phosphates are probably to blame in all of them (few if any).

There is definitely a lot more data coming in to support some benefits of phosphate removal. It's certainly something causing some healthy debate regarding their place in TFPC. What is not helping is when someone latches on to it as the answer to all their problems without even knowing what their level is.

Get a reliable phosphate test. Or don't. It's your pool, you can blindly dose it if you want. Good luck with it.
 
Wow, lots of comments/input, thank you...A response:

1. I'm 99.99% sure it's algae. It brushes off the walls and floor like a green dust cloud. I've rubbed my hand across some tight corners that are tough to access with the brush, and it's light enough to come right off. I haven't tried a white cloth test, but will do so. It appears in random areas on the floor and walls, with no specific pattern. Sometimes it's only noticeable on the floor when brushing. I'll see if I can capture a photo. Oddly enough, the water is crystal clear.
2. The SWG runs for 10 hours per day at 100%, from 10AM until 8PM. I used an SWG calculator to determine run-time, and based it on a 4ppm per day loss. The pump runs at variable speeds for 12 hours beginning at 9AM; higher for the first 4 hours, a bit lower for 4 hours, and then around 1,200rpm for 4 hours, from sun-up to well past sun-down. I haven't determined at what point the algae presents itself, but I typically notice it at varying times of the day. My measurements are usually taken around 9:30AM after the pool pump has circulated the pool for 30 minutes. This morning I tested the water before the pump came on.
3. I've tested the water morning and night, and have never fallen below, or even come close to falling below, the minimum FC indicated in the Pool Calculator for my specific CYA.
4. The pool is exposed to the sun for nearly the entire day.
5. My original post did not indicate a desire to reduce the phosphate levels, but rather to open the topic for consideration/discussion. The last time I had the pool store test my water, they indicated my phosphate level was high enough that it warranted treatment with PhosFree. Of course, I ignored that advice based on the predominant position on TFP that a phosphates were not a consideration in a "properly sanitized" pool. The problem is, all testing results so far indicate that, by the numbers, my pool is "properly sanitized," so something else is at play here.

I guess it could be a circulation issue, but the algae appears on a wall that is directly on the other side of a return, and I can feel substantial water movement in that location, so I discounted a circulation issue. I'm going to do another OCLT test tonight to see what the results are, and I'll post them. I don't mean to open a can of worms, but rather am trying to find a solution to an ongoing problem that has evaded me.
 
Wanted to update this thread with my phosphate results. The pool store measured them at 300ppb, which sounds low enough to not be an issue, so back to the drawing board I go chasing this algae problem. I have a bottle of PhosFree that I must have bought a few years ago, so I may as well use it to lower the phosphate level, but I don't expect it to change my situation. If it does, it'll be a nice surprise.

If I can remember, I'll do an OCLT test tonight/tomorrow to see what's going on with the FC. I have my SWG set to accommodate a 4PPM daily chlorine usage scenario, and FC is steady every day, so I think I'm on target there. I'm going to experiment with my returns to see if I can further improve the circulation of the pool, but at the moment, I'm throwing spaghetti against the wall as I don't have a defined path to follow.

Thanks for the help everyone, it's greatly appreciated!
 
Seadweller said:
I typically try and brush the pool 2 times per week at minimum.
Click to expand...

Try brushing your pool, bring up to SLAM level, allow your levels to naturally come down, but do one thing different. DO NOT SHUT OFF YOUR PUMP! Then, go a few days to see if you have recurring symptoms. If you do not, then I will bet you that what you are seeing is something settling in your pool and not algae. If the water does not sit for any time, you should not be having the same issue.

Algae does not have to be controlled in a perfect environment, unless something out of the ordinary is happening. I believe at one point, the consensus on the forum is that 1 in 10,000 pools do not operate properly at the CYA/FC ratio. Something is happening.

Also, have you done a PR treatment?
 
Just curious, but what makes up a "reliable" phosphate test? We don't trust the pool store for ANY other test (exception..... iron......because most of us are reluctant to spend money on a valid iron test) so why would we even consider the pool store to test phosphates?
 
Seadweller said:
I know the topic of phosphates seems taboo here on TFP, but I'm beginning to think there may be some merit to opening a discussion about this, as I've exhausted every other avenue.
Click to expand...

JimMarshall said:
I can tell you with a properly sanitized pool phosphates are irrelevant
Click to expand...

The verdict still seems to be out on the subject Phosphates Debate

Seadweller said:
Has anyone noticed a dramatic increase in "can't get algae out of my pool" posts?
Click to expand...

I too have noticed an increase in threads with similar topics.
 
PoolguyinCT said:
K-1106 , somewhat handicapped by its ranges.

I have compared it to tti2000 & 3000,l.

K-1106 is as accurate as any hand fed drop test can be.

*** all test were performed by a pool service company.
Click to expand...

The K-1106 can test 0-6000ppb with 250ppb increments below 1000ppb.

I don't believe they recommend you lowering more than 1000-2000ppb per dose, so how is that range handicapped?
 

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