Yellow Algae?

SorryImaNewb123

Active member
Jun 26, 2020
27
Upstate, NY
Pool Size
25000
Surface
Plaster
Chlorine
Liquid Chlorine
Hello,

I have what appears to be yellow algae forming at certain areas at the bottom of my pool. I just shocked my pool a couple of weeks ago with 14 pounds of 70% available chlorine shock as I had green algae forming on the floor previous to this! That did the job to remove the green algae and I then proceeded to remove the dead algae. Suddenly about 1 week after this, I was shocked (no pun intended) when I noticed the yellow algae forming and seemed to be forming around the same areas that the green algae was previously.

Otherwise, my pool looks crystal clear and healthy. I use the basic test strips to measure chemistry and everything looks good. Just as an additional measure, I also brought a sample of my pool water to the local pool store and they said my chemistry is perfect and I didn't need to add anything.

Do I need to add another 14 pounds of a shock to my pool again to kill the new algae? My pool is 36,000 gallons and 20' x 40', which is what the guy as the pool store said I needed to kill the green algae. So confused.

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Here's are some pics showing the spot of Algae that have formed.
IMG_0575 (1).jpg

IMG_0577 (1).jpg

IMG_0576 (1).jpg

Here's the shock that I used previously.

 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,915
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40

SorryImaNewb123

Active member
Jun 26, 2020
27
Upstate, NY
Pool Size
25000
Surface
Plaster
Chlorine
Liquid Chlorine
I added 7 pounds of shock last night to kill what appears to be a fairly small amount algae on couple strips of the pool floor, but this morning there's a white matter all throughout the bottom of the entire pool. My guess is that it's excess pool shock as there is a significant amount of it especially in the bottom of the deep end where the floor meets the wall. How to tell is that's excess pool shock that didn't dissolve or dead algae?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,933
San Dimas, CA (LA County)
So just vacuum with the filter setting ON, then backwash afterwards, right?
You only need to backwash when the pressure rises 25% over clean pressure. And in fact a slightly dirty sand filter filters better than a just-backwashed filter.

What's the difference if you stir things up and the skimmer catches the stuff or if you chase it down with the vacuum? Nothing.
 

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SorryImaNewb123

Active member
Jun 26, 2020
27
Upstate, NY
Pool Size
25000
Surface
Plaster
Chlorine
Liquid Chlorine
OK, I just received the TF-100 test kit. I will try to restate how I understand the SLAM process and you can let me know if I am understanding correctly. I would appreciate if some of my steps below are not correct, can you correct them for me.

1) Get pH level to between 7.2 - 7.5
2) Make sure the CYA is between 30-50 parts per million.
3) Add enough chlorine to shock level (I have shock from Leslie pool supplies, the one I mentioned in my original post. is that ok?)
4) Brush pool often. Let my robot vacuum the pool each day.
5) Check each morning to make sure that the FC is still at shock level, if not add more shock until it is.
6) Keep brushing pool often. Let my robot vacuum the pool more.
7) Check the CC level and make sure that it is 0.5 or lower. Check that the overnight FC test i don't lose more than 1pm FC and water is clear. (note - my water is already very clear, just has some algae that keep appearing at the bottom of my pool)
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,915
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Close.
Step 3 - better to use liquid chlorine. To use Cal Hypo, you need to be sure your CH is low enough. Also be sure it fully dissolves and does not rest on the pool floor.
Step 5 - test every few hours, at least 3-4 times per day, and raise FC back to SLAM level. Not just once per day.
 

Grayman43

Well-known member
May 19, 2019
114
Rockingham, NC
I’m not a expert but feel like I am as am I completing my slam. If you think it might be mustard algae there is a chart to get to mustard algae levels. Mine has been so chlorine resistant I figured I would go to these levels to be safe . The other two guys above me have forgotten more than I know But wanted to add that tidbit. Also please look behind lights and ladders. I found a 4 inch chunk of algae behind my light
 
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