Dead algae/pollen mix or mustard algae?

[singerteacher]

Background: I shocked about a week ago to kill green algae, and simultaneously was dealing with tons of pollen coating my skimmer socks an inch thick. The pool water was yellowish but it's sparkling clear now. I've been vacuuming up what I thought was a mix of pollen and dead algae ... but it keeps reappearing. Could it still be dead algae/pollen mix settling to the bottom? Or is it mustard algae? It's not in shady places, and seems to collect in drifts on the bottom. Here are my numbers:

FC 3.8
CC 0.2
pH 7.8
TA 120
CH 150
CY 50
Sat .5
Temp 60F

I know the FCl loss check overnight is the best way to determine, but I haven't done one because I was killing algae before. It's raining and very cloudy now ... can I do a FC loss test now, or do I need to wait until night?

 

[JohnT]

It's probably new algae growth. Your FC is below the minimum recommended level for a CYA of 50ppm. Try running your chlorine at 6ppm and see if the issue improves.

 

[singerteacher]

New green algae? Or mustard?

I'll up my chlorine level. Do you think it's new green algae or mustard algae? Also, my CYA reading fluctuates every time I take it, although I'm fairly certain it's not changing that much in my pool. It's so hard to tell when the black dot "disappears," and therefore so hard to figure out what the proper FC should be!

 

[DamianS]

Re: New green algae? Or mustard?

I'll up my chlorine level. Do you think it's new green algae or mustard algae? Also, my CYA reading fluctuates every time I take it, although I'm fairly certain it's not changing that much in my pool. It's so hard to tell when the black dot "disappears," and therefore so hard to figure out what the proper FC should be!

I have no idea about the different kinds of Algae.

When was the last time you added CYA? I just ask because if it was recent, there might still be some dissolving and that might give you different CYA readings.

Most likely, you're just having a hard time telling when the test is complete (I do too!). Here are pictures from Taylor on how to read the CYA test.

 

[singerteacher]

I've never added CYA myself -- it existed when we got the house last year. It's lower than when I first started, due to using BBB instead of pucks and lots of backwashing while getting rid of the algae. I think the fluctuating CYA problem has been due to my reading of the test. I've been trying to get the black dot to completely disappear, but in actuality I just need to get it obscured. The pictures from Taylor were so helpful! Thank you!

 

[JohnT]

Mustard algae is usually worse in the shady parts of the pool, and it tends to like shady walls more than any other spot.

 

[PaulR]

I've been trying to get the black dot to completely disappear, but in actuality I just need to get it obscured.

No, I think you really do want it to completely disappear. You should not be able to tell where the black dot ends and the white ring around it begins.
--paulr

 

[singerteacher]

Re: CYA test. When I look at the pictures posted on the Taylor website (link above), I can still make out the black dot. But Taylor says that's finished. So, that's what I'm going on.

 

[JasonLion]

No, you can't. What you are seeing is the bottom of the tube. The black dot is smaller.

 

[singerteacher]

So, are you saying that when performing the CYA test, you need to be absolutely certain that you can't see the dot? (I can make out the dot for quite a long time beyond when it's really quite obscured in my kit.) That will give me lower CYA readings than when I stop when I'm having trouble figuring out whether that's a dot or not ... and allow me to maintain a lower chlorine level. (For lack of better terms, there's a point when "I'm not sure whether I still see the dot," and more drops later there's a point when "I'm positive I can't see the dot any more.")

 

[PaulR]

What I do is when I get to the not-sure stage, I move the tube around a bit. Eyes are better at catching something in motion. If I wiggle the tube a little, often I can still make out the black dot. Put in a little more stuff, then even wiggling I can't make it out, and I'm done. I've had very consistent results since I started doing this. (I always do the view-tube step 2-3 times to be sure.)
--paulr

 

[JasonLion]

Higher CYA level do mean that you need to maintain higher FC levels, but you actually use less total chlorine at higher CYA levels.

 

[singerteacher]

I will try the tube wiggling. :lol:

JasonLion, can you elaborate on why a higher CYA level means that one uses less total chlorine? And, what is the suggested goal level for CYA? I can't get the Pool Calculator to give me TFP's number. Thanks!

Edited to add: BTW, I had 0 FC loss overnight. It's dead algae/pollen. Whew.

 

[JasonLion]

CYA protects chlorine from sunlight. The more CYA you have, the less chlorine is lost to sunlight each day. It happens to work out that the extra protection from sunlight more than compensates for the higher FC level as long as you don't need to shock the pool.

We recommend CYA between 30 and 50 for most pools, but between 70 and 80 if you have a SWG, and somewhere in between if you have really intense amounts of sunlight, direct sun on the pool all day in an area with very little cloud cover.

 

[singerteacher]

Help! Really confused now!

Can you have minimal FC loss overnight, CC .5 or less, and still have mustard algae? I've been keeping my FC at 6ppm or higher, testing it overnight and either not seeing a FC drop at all or seeing a very small drop. Usually no (or next to no) CC.

So what is this stuff that keeps returning to my pool? 1 -- Yellow powdery stuff on the steps. 2 -- A algae-looking blob under the return, that eventually multiplies all over the pool. 3 -- Faintly yellow skimmer sock.

Last night, I vacuumed for the second night in a row, tested my FC after sundown and it was 8.5, with 0 CC.

Tested again a couple hours after sun had been hitting the pool (busy morning) -- FC was 7.5, with .5 CC. (Testing with the smallest amount of pool water to save reagents.)

I'm thinking it's mustard algae, and that the "if you lose 1ppm or less FC overnight it's not MA" rule doesn't apply to my pool. I'm off to purchase liquid chlorine for my next shocking adventure ...

 

[frustratedpoolmom]

I think if it was mustard algae, your chlorine demand would be much higher. I suspect its dust or pollen.

 

[pepsiholic]

It's probably just a lot of pollen. I pulled out my skimmer sock after 1 day and it was about half an inch thick all over the sock. Kind of nasty but harmless. It was yellow and there was a lot of it! Hope this helps to put your mind at ease

 

[cubbybeave08]

Re: Help! Really confused now!

Can you have minimal FC loss overnight, CC .5 or less, and still have mustard algae? I've been keeping my FC at 6ppm or higher, testing it overnight and either not seeing a FC drop at all or seeing a very small drop. Usually no (or next to no) CC.

So what is this stuff that keeps returning to my pool? 1 -- Yellow powdery stuff on the steps. 2 -- A algae-looking blob under the return, that eventually multiplies all over the pool. 3 -- Faintly yellow skimmer sock.

Last night, I vacuumed for the second night in a row, tested my FC after sundown and it was 8.5, with 0 CC.

Tested again a couple hours after sun had been hitting the pool (busy morning) -- FC was 7.5, with .5 CC. (Testing with the smallest amount of pool water to save reagents.)

I'm thinking it's mustard algae, and that the "if you lose 1ppm or less FC overnight it's not MA" rule doesn't apply to my pool. I'm off to purchase liquid chlorine for my next shocking adventure ...

Does it look like sand on the bottom of the pool? If it does then it is probably dust and pollen...One thing to do is check itside your filter...I sometimes get so much tht it sits in the bottom of my filter like sand. when I pick it up it actually feels like sand. Does it sit all over the bottom of your pool in all the little dents and crevices? It does that because it escapes the circulation there. So it sounds like dirt to me.

 

[singerteacher]

No, it doesn't look like sand. On the steps it looks like yellow powder, and on the bottom of the pool it looks like teaspoons of green/brown/yellow-colored slurry. It seems like the teaspoons "multiply" -- in the early morning, there's one small one, then by mid-day there are more. It does seem to accumulate in the step texture and bottom seams.

I've attached a few pictures. Keep in mind that I vacuumed thoroughly last night and the night before. :x

If this is dust/pollen, how do I get rid of it? I've vacuumed two nights in a row, backwash often, and use skimmer socks, but it doesn't seem to be reducing the amount of stuff that I need to vacuum. Honestly, pretty much the same amount of stuff eventually returns. Is there something wrong with my sand filter? I've vacuumed with a skimmer sock and without one, and it doesn't seem to make any difference.

I'd almost prefer that it were mustard algae, because then I could shock the heck out of it and be done!

 

[singerteacher]

Check inside my filter?

How do I check inside my filter? I've never opened it up!