DE or Mustard Algae

[Deuceswild7284]

So. I have been thinking DE has been coming back into the pool. We had this happen towards the end of last year. When I would turn in the filter it looked like cloud dirty water going into the pool via return jets. It would be like this for like 10-15 seconds then it would stop.

We opened our pool a few days ago and it was very clear. Dirty on the bottom from leaves dirt etc and thought it was some left over DE from last year. I vacuumed the entire pool and brushed it the next day. It would cloud up and disintegrate when brushed. Tested the water and everything checked out well except for the CYA which was around 80 with FC at 4.5. Yesterday I noticed what looked like DE once again. Today same thing a bit more maybe from having the filter on again. It’s not on the sides. Mostly on the bottom and in the ridges. Doing more reading I’m freaking it’s mustard algae. It’s a grayish color. Also included a picture. Any thoughts and help is really appreciated.

 

[YippeeSkippy]

My vote is simply dust in the pool. Mustard algae is not common, especially as the water has been cold.

I'd say brush, brush, brush and get your chemistry in line before you panic.

Can you give us:
FC
CC
pH
TA
CH
CYA

those help us diagnose problems.

Maddie

 

[mknauss]

Most likely dead algae unless you know your filter is compromised.
Did you follow the FC/CYA Levels last year for FC?
You will want to lower your CYA with a partial drain.
Can you complete a signature?

 

[Deuceswild7284]

Here are my numbers from the other day.

FC - 4.5
CC - 0
pH - 7.5
TA - 160
CH - 250
CYA - 80

 

[Deuceswild7284]

Most likely dead algae unless you know your filter is compromised.
Did you follow the FC/CYA Levels last year for FC?
You will want to lower your CYA with a partial drain.
Can you complete a signature?

We got the house in August. Previous owner took care of it and it was crystal clear when we moved in. A couple weeks later it did go green as I found out the chlorinator all of a sudden broke so there was 0 chlorine. I took it to the pool store and they ran an elaborate test and said I needed 32 gallons of liquid shock. I was a newb so I did what they said and the. Green was gone in a day then cleared up even more a couple days later. After that I kept taking samples of water to the pool store to test and did what they said. Again being a newbie just went with it and spending more money then I thought. Haha. Then found you guys.

Can you elaborate what i should put in my sig? Just pool type and size?

Thanks all for the help and insight.

 

[mknauss]

FC/CYA Levels
Riding the FC pretty low.
Can you fill out your signature please?

 

[mknauss]

Take a look at my signature for a guide. If you are on a mobile device, turn it sideways to see mine.

 

[Deuceswild7284]

Ah ha. That was the trick. Sideways. Haha.

 

[mknauss]

With a vinyl liner you can only drain down as far as 18" above the shallow end. So it may take two drain and refills to lower your CYA.

We do have an exchange method that takes some planning but then your pool water level is not changed while the water is exchanged.

 

[Deuceswild7284]

Ok. Thanks for the info.

Should I treat what I see in my pool as mustard algae? Any advise on what to do or how to approach?

 

[mknauss]

Even if mustard algae, you do a normal SLAM until you pass then raise your FC to MA SLAM level for 24 hours, then maintain higher target levels. See the link at the bottom of FC/CYA Levels for the mustard algae levels.

 

[moreira85]

It looks like you have the same issue I have. I had DE leaking back to the pool when the pump would turn off because of a suction leak. Once I found the leak on suction side of pump the de didn’t come back out from the jets. Also looks like what u have on the bottom of your pool is what I have. I slammed the pool and still get some. It keeps coming back in the same spot right where shallow end meets the deep end which it appears like yours.