A little bit of algae

[Eastern]

We live in SC and keep our pool open all year. The temperatures have been low enough that we haven't had to pay to much attention to water chemistry, but this week with higher temps, some algae has started to grow here and there (looks like mustard algae to me). I'm wondering- since there is only a little algae, and the water is only slightly cloudy- if we may just bring FC up to normal levels, or if we need to do a full SLAM.

Thanks!

 

[jblizzle]

ANY algae = SLAM

With the water still cooler and catching it early, the process should go quickly.

 

[woodyp]

Cheaper and quicker to SLAM it now for sure.

 

[pooldv]

yep, I had the same issue a couple of years ago, cool water temps fooled me. Didn't know about SLAMing back then. Took a while to kill it slowly, but the biggest problem was the constant cleaning of the cartridge filter. Algae can clog up a cartridge filter in a hurry, like a day or two.

 

[Patrick_B]

Another vote for Slam. It's a must to beat any significant amount of Algae. If you see some, it's always advisable.

Not sure, but you were debating a re open a while back? I'd say it's plenty close enough now.

 

[Eastern]

Thanks, everyone. SLAM it is.

Patrick, you must be thinking of someone else.

 

[Patrick_B]

I'm sorry, guess so now I re read this.

Go ahead with the SLAM, and let us know if you need help.

 

[Eastern]

So I'm SLAMing today. FC is staying fairly high between tests, but the water is getting greener. Is that normal? I'm on my 4th cycle now.

 

[jblizzle]

What is your CYA? What FC level are you maintaining? How low is it dropping between tests?

It could just look more green as algae is dieing off and clouding the water.

 

[Eastern]

CYA is about 30, maintaining FC at 19 (mustard algae level-it looked yellowish before brushing) and only dropping a few points between tests.

 

[jblizzle]

99% chance you do not have mustard algae. And even if you did, that is not how you get rid of it (as the Mustard Algae article in Pool School explains). You need to follow the normal SLAM process and that is maintaining a FC level of 12ppm for a CYA of 30ppm.

 

[Eastern]

Oh no! I didn't know there was a mustard algae article. I just went with the 19ppm that pool math gave me. Off to read....

ps-why do you think it's not mustard algae? The spots on the pool walls/floor were a yellow/brown/green color, concentrated on the shady side of the pool, and look the google images I found online.

- - - Updated - - -

Okay, I see now that if it is mustard algae, I should have slammed at normal levels and then raised to mustard algae levels. Is there any harm done in raising it high first, during the slamming process?

 

[jblizzle]

There are 1000s of species of algae. I suppose it is possible, but it is much more rare than you would think.

- - - Updated - - -

No harm if you do not keep the FC that high for too long.

 

[Eastern]

Okay- 24 hrs. right?

Any thoughts on why the water is turning greener (its really a green/yellow)?

 

[jblizzle]

cloudy or clear? High FC levels can turn the water colors if you have metal in the water.

 

[Eastern]

Just a little cloudy. We do have iron in the water.

 

[jblizzle]

Then it is likely the iron making the water yellow (looking green in a blue pool) ... made worse by taking the FC so high. Hopefully you will not end up staining the liner.

 

[Eastern]

Ugh, just did an ascorbic acid treatment last month. I did lower pH to 7.0 before slamming, so maybe we'll be okay.

So I guess I should just let the FC level fall naturally over the next few days? The level is holding steady now.

Thanks so much for your quick replies. I really appreciate the help!

 

[jblizzle]

It should drop to normal SLAM level in a day or so.

Did you add metal sequestrant after the AA treatment and before the SLAM?

 

[Eastern]

No. This is a new home/pool for us, so I was curious to see what would happen without sequestrant. We'd rather deal with stains than have to purchase monthly sequestrant.