Yellowish/Greenish/Brownish Powder on bottom of pool

[Cabrera1016]

Hi all!

We've been seeing some powder deposit on the bottom of our pool lately. For a background, our solar cover was disintegrating so we had the cover off the entire week until the new one came. It was a very HOT week, and our FC was close to 0. (we usually keep it close to a 1.) Well, we learned that our FC should be between 5-7 with a CYA level of 40 (which we just increased ours to) so we started increasing the FC to 5. Well, just yesterday, we removed our cover and had even MORE of that odd brown/yellow/green powdery substance, that would dissipate upon stepping on. It did not seem slippery when stepping on it either. Last night, I made sure to get the FC to a 7, and we will keep it between a 5-7 from now on. This morning when I looked under the cover, I did not see evidence of that powdery substance settled on the bottom.

Does anyone know what this stuff is?

Thanks!
Stephanie

 

[PoolStored]

Algae.

 

[Cabrera1016]

Algae.

How is algae possible, as stated above with the background and the chlorine and stabilizer? From what I understood, algae is slippery and does not dissipate when stepped on.

 

[PoolStored]

It was a very HOT week, and our FC was close to 0. (we usually keep it close to a 1.)

^^This.

Follow the SLAM process to clear your pool. Link-->SLAM Process

What water test kit do you have?

 

[Cabrera1016]

Ugh. That sucks!! This morning (after I added chlorine last night) - the stuff does not seem to be on the floor anymore....I had added chlorine to get it up to a 7.

We have cheap test strips but I'm going to get the far more elaborate "chemistry set" test kit that my Mom has for their pool.

 

[PoolStored]

Here are the recommended kits. Link-->Test Kits Compared

 

[Cabrera1016]

Here are the recommended kits. Link-->Test Kits Compared

Thank you! Yep - my parents have the kit on the far right of that list. I will take a look at the SLAM technique - but if there is no more of that stuff on the bottom of the pool, should be ok at this point? I am ordering that test kit today!!

 

[PoolStored]

Do this test. You need the kit to do this test. If you fail, then you SLAM. Link-->Overnight Chlorine Loss Test

 

[JamesW]

It is Mustard Algae.

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.troublefreepool.com

 

[Debmellon5]

Hi all!

We've been seeing some powder deposit on the bottom of our pool lately. For a background, our solar cover was disintegrating so we had the cover off the entire week until the new one came. It was a very HOT week, and our FC was close to 0. (we usually keep it close to a 1.) Well, we learned that our FC should be between 5-7 with a CYA level of 40 (which we just increased ours to) so we started increasing the FC to 5. Well, just yesterday, we removed our cover and had even MORE of that odd brown/yellow/green powdery substance, that would dissipate upon stepping on. It did not seem slippery when stepping on it either. Last night, I made sure to get the FC to a 7, and we will keep it between a 5-7 from now on. This morning when I looked under the cover, I did not see evidence of that powdery substance settled on the bottom.

Does anyone know what this stuff is?

Thanks!
Stephanie

Hi Stephanie, We have a 2 year old 18,000 gal saltwater fiberglass pool. We live in SE Penna and the pollen this year was very heavy. Even closing the auto cover at night, we still had tons of pollen in our pool. Your description sound like and the photo looks like the pollen we had in our pool in May. We put our vacuum and skimmer in every day and routinely brush the surfaces. Now we have minimal powdery stuff but with brushing it disappears (hopefully into the filter). We also use "hairnets" Amazon.com daily to line our skimmer and that collects a ton of pollen and bugs and makes the skimmer easy to empty. Hope this helps!

 

[Cabrera1016]

Do this test. You need the kit to do this test. If you fail, then you SLAM. Link-->Overnight Chlorine Loss Test

Ok I was just going to ask if there was something we can do before having to do the SLAM. I have my parents test kit so I will perform the overnight FC loss test!

 

[PoolStored]

The OCLT recommendation was a mistake on my part. With visible mustard algae, when you have the test kit, start the SLAM.

 

[Cabrera1016]

The OCLT recommendation was a mistake on my part. With visible mustard algae, when you have the test kit, start the SLAM.

What about the other poster who said it looks like the pollen problem that SHE has?

 

[PoolStored]

We are well past pollen season in our lattitude. You have a TFP Expert and guide telling you to slam. If you are concerned, do the OCLT. Twer it I, I'd get the slam going.

 

[Cabrera1016]

We are well past pollen season in our lattitude. You have a TFP Expert and guide telling you to slam. If you are concerned, do the OCLT. Twer it I, I'd get the slam going.

Gotcha. Understood. Thank you for that clarification!

 

[JamesW]

99.999% sure it is Mustard Algae.

 

[Cabrera1016]

So I just tested our CYA with the testing kit and it's at a 50. I then tested the FC and it's a 4. With those numbers, IS this algae? As I added chlorine last night to get it to a 7. So from about 7pm into 3:30pm we only lost 3. We are shocking it now.

Is mustard algae powdery and disappears easily?

 

[JamesW]

Is mustard algae powdery and disappears easily?

Yes.

In my opinion, it is mustard algae.

 

[JamesW]

In fact, If there was a Dictionary entry about Mustard Algae, this is the picture I would use.

 

[Cabrera1016]

In fact, If there was a Dictionary entry about Mustard Algae, this is the picture I would use.

View attachment 591254

This was taken out today. After we had vacuumed it thoroughly yesterday.