High Phosphates in Pool & Algae Growth All of a Sudden?

[ShokWaveRider]

I have been struggling to clear my pool of Phosphates and what appears to be Yellow or Green Algae. Not a huge amount of Algae but re-occurring nevertheless. However the pool water is clear (until I put phosphate remover in it) and not green. The Algae collects on the floor and walls after about 24 hours but can easily be brushed away. I think after 2 weeks the Algae is probably Mustard as opposed to standard Green Algae as I increased the Chlorine to <15ppm and it is still there. All other items like PH, Alkalinity, Stabilizer, Calcium etc. are all in perfect balance.


I have been using Super Phosphate remover for almost 2 wees and a I am on my second bottle (Not cheap). I just ordered some Yellow Treat (Sodium Bromide) to see if that helps. It is getting Tedious. Pool Temp is currently ~80 degrees and dropping as it is getting cooler.

This is the first time I have had this problem for over 10 years and I have always done my own pool maintenance.

Any pool experts out there that can offer some pointers?

 

[Cobra9777]

Sounds like the dreaded mustard algae. This is the worst possible kind of algae. Very hard to get rid of. I had the same problem... kind of a dusty algae on walls and floor. It was easy to brush off... made a yellowy, greenish-brown cloud when brushed. But then returned after a couple days even with chlorine levels very high and everything else in balance. After several frustrating weeks and much research, the cause turned out to be high phosphates. Here's what I did to rid my pool of this beast:

1. Bought the Taylor phosphate test kit (K-1106). My initial reading was well over 1000ppb.
2. Stopped using stabilized chlorine (contains cyanuric acid, CYA). Used only liquid chlorine.
3. Reduced CYA as much as possible, to around 20-30ppm or lower. I had to drain some water and refill to get it that low.
4. Raised free chlorine to 20ppm and held it there for 3 weeks. (more effective with lower CYA)
5. During the 3 weeks, I dosed regularly with Orenda phosphate remover (PR-10000).
6. Brushed daily, ran the filter 24/7, and ran the Polaris cleaner about 4 hours per day.
7. Tested for phosphates every other day. It came down steadily but did require a lot of the Orenda product.

At the end of the 3 weeks, phosphates were near zero and I slowly let the free chlorine come down to normal. The algae was gone and I've had no trace of it since.

Good luck.

 

[ShokWaveRider]

Thanks Cobra, look like what I have. I am about 1 week into the process. I will certainly take your advice when I have exhausted the current schedule if it persists.

 

[ShokWaveRider]

Cobra: I have a Salt Water Pool so I am generating relatively good Chlorine. I put some phosphate remover in this morning and it clogged up the filter quite fast. I cleaned the filter and am running for another day. I did test the phosphates, and they are down slightly. But that has happened before. as you say it is a long and quite expensive process. When I get the Mustard Algae killer I will dump that in too.

 

[Cobra9777]

My experience is that salt water chlorine generators will only maintain free chlorine at around 1-3 ppm on average. That's an OK maintenance amount but it's not nearly enough to kill mustard algae, especially if your CYA is too high (a common symptom of using stabilized chlorine over a long period of time).

You have two objectives: (1) get the phosphates down to near zero to prevent future mustard algae, and (2) get the free chlorine up to a "super shock" level for an extended period to kill the existing algae. Mustard algae is resistant to normal chlorine levels, even normal shock levels. Depending on your CYA level, you need to get the chlorine up to somewhere in the 12-20 ppm range.

I'm not sure what phosphate removal product you are using but I don't think it should be clogging the filter. Again, I'd highly recommend the Orenda PR-10000 product. I had no clogging issues, although it's pricey and it did take a lot more doses than indicated on the label.

 

[ShokWaveRider]

My experience is that salt water chlorine generators will only maintain free chlorine at around 1-3 ppm on average. That's an OK maintenance amount but it's not nearly enough to kill mustard algae, especially if your CYA is too high (a common symptom of using stabilized chlorine over a long period of time).

You have two objectives: (1) get the phosphates down to near zero to prevent future mustard algae, and (2) get the free chlorine up to a "super shock" level for an extended period to kill the existing algae. Mustard algae is resistant to normal chlorine levels, even normal shock levels. Depending on your CYA level, you need to get the chlorine up to somewhere in the 12-20 ppm range.

I'm not sure what phosphate removal product you are using but I don't think it should be clogging the filter. Again, I'd highly recommend the Orenda PR-10000 product. I had no clogging issues, although it's pricey and it did take a lot more doses than indicated on the label.

I am running about 15ppm chlorine. I just ordered some of your recommended PR-10000. So All should be good come next week. Thanks again for your recommendations.

 

[txtig]

I fought algae for years during the hot summer months until someone told me about PoolRx. It’s a small canister that you put in your pump basket. It’s supposed to last six months, but since I never have algae problems in the winter, one canister lasts me for a full year. I place the PoolRx canister in my pump basket in the spring and I never have any algae problems. It really is amazing. I buy them on Amazon. They come in several different sizes dependent on the size of your pool.

 

[Rianne]

This post made me think of Florida.

 

[FlaGator]

I went through this in SoFla.

The only thing I would add is to clean your filter within a few days of using the phosphate remover to ensure it's completely removed from the system. I had a cartridge filter, and cleaning it monthly with a bleach washdown helped with algae as well.

 

[ShokWaveRider]

I have a cartridge filter, I am cleaning it every 2 days right now while trying to lower the phosphates.

 

[ShokWaveRider]

Finally fixed this.

1) Use "Yellow Treat" to get rid of the Mustard Algae (Yellow). Be CAREFUL to do exactly what it says otherwise you will end up with a Bromide Pool.
2) Bring Chlorine down to recommend levels and make sure they stay there for a few days.
3) Use PR-10,000 Phosphate remover per instructions.
4) Clean filter regularly.
5) When all was done I replace the filter with a new one.

Thanks to those who helped.