Can this be the beginning of yellow algae?

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
I had greenish algae on the walls of my pool in mid June. Eversince then, I have been watching for it to come back after I treated it. During the last 2 days, I noticed a yellowish tint on some parts of the wall. I thought it was just shadow from the shrubs and trees nearby. I touched it and it did not feel slimy. When I brushed the pool today, I saw little clouds of dusty stuff coming off some parts of the walls. I wonder if that is the beginning of yellow algae. When I had algae before, it was greenish. After I brushed, I still see some yellowish tint on the walls. My test result for CC was 0 this morning so I wonder if something is causing the stain. It is easier to distinguish the difference on the steps. The top of the steps do not have the yellowish tint but the sides of them do. Not all of the sides, just some. Had this happen to anyone else?
 

lightingguy

LifeTime Supporter
Jun 17, 2010
513
Glendale, CA
Our issue was kinda like this. We defeated the algae, then worked out the calcium clouding - and then after all that had little patches of yellow that would crop up. Our plaster is really deteriorating and pitted - I can only assume it creates a lot of pockets for small colonies to avoid a gentle scrub. I'd hit them with a hard bristle brush whenever they became visible and eventually it stopped. They haven't come back this summer.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,713
Sebring, Florida
You are making a good description of mustard algae.

In your other thread, one of us ESPECIALLY me, should have asked you how your water looked.

You will need to shock your pool....sooner rather than later.

Do so according to theinstructions in Pool School and your water will return to crystal clear.
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
The water had been crystal clear since I used Phosfree on the algae in mid June. It has not been cloudy since so I did not think anything of it. The only cloudy part is towards the areas where I see yellowish tint on the wall. The water around those areas look sort of fuzzy. I will check the pool again tomorrow morning. With CYA at 35 or 40 according to pool school, I need to get FC to 16, right? I will need to get more bleach in order to do a shock. Can I do a partial shock since I don't have enough chlorine on hand? Partial shock as in putting in a little less chlorine than shock level. In my case, I need 3.7 jugs of 182 oz of bleach to get to 16 according to the pool calculator and I only have 2.5 jugs left. That will get me to 12. Please advise. Thanks.

By the way, I did a test of FC and CC this evening. FC went from 4.5 this morning to 4.0 and CC remains at 0. Here is a summary of my FC results during the past few days:

7-29-10 4
7-30-10 5
7-31-10 3 and then 4
7-31-10 2.5 added 90 oz of 6% bleach
8-1-10 4.5

I thought decreases in FC from one day to the next is normal. No?
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,713
Sebring, Florida
1. Phosfree is unrelated to killing algae...don't waste your money.

2. If you see yellow on the wall and have cloudy water, you need to shock...regardless of numbers.

3. Yes, 16ppm is shock level with a CYA of 35-40

4. A partial shock, by our use of the term, doesn't exist. Shocking is a process that involves repetitive additions of chlorine and results in crystal clear water. Get more bleach. Read How to shock your Pool in Pool School. You'll need quite a bit more than 3.7 jugs.

I thought decreases in FC from one day to the next is normal.
Absolutely. FC is decreased by the sun and the organics (algae) in your pool.
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
Test results from this morning:

pH - 7.6
FC - 4.5
CC - 0
TC - 5 or 4.5
TA - 90
CH - 370
CYA - 40

Didn't I read somewhere that the pH should be low before shocking the pool? Mine went up again for some reason. Regarding keeping the level of chlorine at shocking level, how do people do that when they have to go to work during the day? After I get enough chlorine and bring it to shocking level, I won't be able to monitor it since I have to go to work. How much chlorine do you think I will need?
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
I went to HD and got 12 gal of 10% chlorine. I reduce pH down to 7.3 from 7.6. I read somewhere that I need to get to a higher level of FC for yellow algae. In my case, it was 24. I thought I added the right amount the pool calculator said - 5 gals + 1 quart - but when I tested for FC 1.5 hours later, I got 29.5. I hope that is not too much. I also tested CC, it is 0. I brushed the whole pool. The water is still clear. I did not see a lot of cloudy areas when I brushed. The pool pump will be running overnight. I will test for FC and CC tomorrow morning. If all looks good, should I just not add anymore chlorine and let it get back to normal?
 

kenmccall

LifeTime Supporter
Mar 24, 2009
77
Macon Ga
Because the algae is consuming the chlorine overnight. You will need to get you shock level back up to where it needs to be and try to maintain it there as much as possible. When you have less then 1 PPM drop overnight and everthing is clear the shock process is over and then time will lower your chlorine back to the proper level for your pool.
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
Tested FC this morning. FC level drop 2 from last night. CC is 0.05, it was 0. Shocking continues.........

I read somewhere that I should maintain the high level of FC at 24 for a couple more days after shocking. That means keeping FC at 24 without the pump running 24/7? Is that true? Thanks.
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
You should be able to let it drop to normal, but run with a slightly higher "min" than normal. Use your old "target" as your "min". Hope that makes sense...

Be sure to brush anywhere it could be lurking, behind ladders, light niches, etc. treat floats, pool toys etc. and wash all suits and towels in hot soapy water.

If you see it return as the levels drop to normal raise it back up again. If it's coming back you need to figure out a way to increase circulation- brush the pool daily if you can.
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
Thanks. My FC test results this morning was confusing so I tested twice:

FC last night was 24.5. This morning it was 25 and CC was 1. I went to another area in the pool and got a different batch of water. Then FC was 23 and CC was .5. I added more chlorine to get it to 24 again.

One of the problems I have is the landscape around the pool. Part of the pool is surrounded by rocks. Anything besides spiders can hide under there between the plastered rocks and the water line. There is a white line above the water line from scaling. It turned green when I had algae before. Most of the green disappeared after the algae was treated in the past but not all. Part of the scaling turned brownish. I sprayed 10% chlorine all over those areas last night hopefully all the brownish stuff will disappear. Unless we splash a lot in the pool, those areas don't always come in contact with the water. Any suggestions how to get rid of greenish/brownish scaling between the rocks and the water?
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
I have not taken any pictures yet. I will post pics when I have them. I tested the water this morning. FC is 26 (I tested twice) when it was 28 last night at 9:45pm. I added chlorine to get FC to 24 but I got 28. I started this shock process on Monday night. It has been 4 nights and the overnight FC loss test is still more than 1. Is this normal? The water in the pool had always been very clear. It is like glass now.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,713
Sebring, Florida
I added chlorine to get FC to 24 but I got 28.
Not that uncommon when you first start testing and dosing carefully....perhaps your pool is a little smaller than you think? Many things can affect that.

Anyway, it is not all that uncommon to take four days to get your overnight loss down to less than 1ppm. Remember, the 1ppm loss is a guideline and does not mean you are in terrible shape until hyou get exactly to that point.....it is a target and you're making progress to that target. Others have taken less time, some longer.

We often use these three criteria to determine when you are finished shocking.....

1. Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1ppm.

Again it's a guideline or target but you already have at least one of them met so you're getting there.
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
Hi Dave, thanks for the words of encouragement. I know what I did regarding the chlorine level. After I added the required amount of chlorine to bring it back to 40, I had just a little bit left in the pitcher so I just dumped the rest of it in there. Also, when I had to measure it in cups, etc, I probably did not do it just right. It won't hurt if the chlorine level is a little over target level, will it? I had already gone through 11 gals. of 10& chlorine. I need to get more. I guess I answered my own question in the other post.

I got the pool size wrong when I first joined this forum. Then I found the paperwork for the pool and it says pool capacity is 27,000 gal. It is a freeform pool. I assume the pool builders know what they are talking about when they put it down on paper.
 

kal2002

LifeTime Supporter
Jul 4, 2010
235
northern California
Added chlorine over an hour before the tests and targeted FC at 24. Tested the water twice. I got FC at 23 and at 25 from 2 different batches of water and within 10 minutes. So should I say FC is 24?
 

Other Threads of Interest