Possible Mustard algae with CYA 80

[JamieP]

This wasn't supposed to happen again, but due to various factors I am SLAMIng for the second time in a month. Ugh. In the process of cleaning everything diligently, I was looking in my skimmer and above the water line, where I had a residual plaster dye stain (I don't know why I never scrubbed it off before, but I didn't...) I noticed some yellowish brown. I used a magic eraser to easily remove the dye, but the yellowish-brown stuff was rougher and took more scrubbing to remove. It left a slight yellow stain on the inside walls of the white plastic skimmer. I didn't think anything of it, but in doing some reading here I realized with alarm that it might be mustard algae.

Does this sound like mustard algae? If so, how do I proceed with my SLAM? Do I still aim to pass the OCLT at regular SLAM levels and then bring it up to Mustard Slam levels for 24 hours? How do I know when I'm done? One trouble is that I am at a CYA of 80 for my SWG so it's going to take a boatload of bleach. What do you recommend?

 

[pooldv]

Re: Mustard algae in skimmer?

Yes, that is basically the process. SLAM, pass SLAM and then mustard level for 24 hours and you are done. If it was a teeny bit after a SLAM already and you pass an OCLT then I would just brush that spot regularly and keep an eye on it. And brush a little more diligently if you are a brush slacker like I am!

More on mustard algae here, Pool School - Mustard Algae

 

[JamieP]

Instead of starting a new thread, I changed the title to better fit with my new questions...

I've been tying to finish off a regular SLAM when I realized (as described in my first post) that I needed to scrub above the water line in my skimmers. Dumb me, I had been scrubbing, but not bothering to remove the plaster dye stain that was there from when the pool was built. When I went to do this, not only was there the blue as seen in the picture below (this is an older picture from when the dye was newer and not as faded), but there were also some patches of brown above the waterline to the rear of the skimmer tub. I scrubbed at everything with a magic eraser and the eraser slipped easily over the dye stains removing them, but it took some elbow grease to remove the brown ring above part of the waterline. In one skimmer, the brown ring left a tan/yellow staining on the white plastic once it was removed. I don't for sure recall touching the brown stuff with my hand, but impression I had of it was that it was rough since it took some scrubbing to remove. At the time I just thought it was dirt, otherwise I would have been more proactive in taking a picture or something to help identify it.

An older picture of skimmer with dye. This was months ago, before the brown I scrubbed off last night:


The other skimmer, now clean, but you can see a faint yellow discoloration above the waterline. FYI, the water sometimes gets higher than it is now, depending on how much I top it off and if the overflow valve is closed. I don't think it fills as high as the brown/stains are, but the water would certainly splash that high.


It was last night that I scrubbed this off, and the pool did seem to consume more FC overnight than I had expected since I'd been SLAMing for 4 days and tests were coming in well.

So... Does this sound like mustard algae? The pool is clear and never had any visible signs of algae, just a higher demand on the SWG that made me suspect I needed to SLAM which was confirmed with an OCLT. I have not, and do not see any other spots of brown or any other color on the pool interior.

With my CYA of 80 it's going to take copious amounts of bleach to maintain MA shock level and I don't want to do it if I'm just being paranoid. I still need to pass the OCLT, but once I do (hopefully tonight!) I want to be ready with my plan of attack.

Thank you for your opinions!

Oh, and here are my current test results:

FC: targeting 31
CC: 0 or 0.5 but not checking every time
PH : brought down to 7.2 before SLAM
CH: 275
TA: 70
CYA: 80
Salt: 3400

 

[pooldv]

I would spray those areas with some 4 to 1 diluted bleach daily and brush it for a few days and forget about it unless you see some algae in the pool or have a bad OCLT.

 

[JamieP]

I would spray those areas with some 4 to 1 diluted bleach daily and brush it for a few days and forget about it unless you see some algae in the pool or have a bad OCLT.

Thanks pooldv. That certainly sounds easier. But just to clarify...

4 parts bleach to 1 part water
or
4 parts water to 1 part bleach?

 

[pooldv]

4 parts water 1 part bleach.

 

[duraleigh]

That's not mustard algae. mustard algae is usually on the pool floor and walls and will brush off VERY easily. Wherer you have that stain around the skimmer is sometimes almost impossible to get off. My pool had it to a lesser degree and I could never remove it. poolodv's idea of the spray is a good idea and just may do it.

Meanwhile, I would ask your PB to come do some warranty work. That seal from the top of the skimmer to the bottom of the decking is nasty and unfinished and will harbor everything under the sun. Surely he can do better than that. That can be all cleaned up in 30 minutes work and you shouldn't have to do it.

 

[JamieP]

That's not mustard algae. mustard algae is usually on the pool floor and walls and will brush off VERY easily. Wherer you have that stain around the skimmer is sometimes almost impossible to get off. My pool had it to a lesser degree and I could never remove it. poolodv's idea of the spray is a good idea and just may do it.

Meanwhile, I would ask your PB to come do some warranty work. That seal from the top of the skimmer to the bottom of the decking is nasty and unfinished and will harbor everything under the sun. Surely he can do better than that. That can be all cleaned up in 30 minutes work and you shouldn't have to do it.

Thank you very much for chiming in, Dave. I'm relieved to hear your opinion that it's not mustard algae. I'm not really concerned about the looks of stain, only that if it were algae that had been there, it would reappear somehow if I didn't raise my levels to MA slam level.

You're right about now bad that skimmer looks! We haven't had time to pay much attention to it even though it's annoying because the hair net/skimmer socks I use get caught on that junk when I try to lower the skimmer basket. Unfortunately, I have no PB to turn to since we did an owner build. Can you advise me on how to remove it? It's a combination of duct tape that didn't tear away cleanly and concrete.

 

[JamieP]

Ok, so I went out there with a utility knife and got the tape off. Some of the cement chipped off too and now it looks like a much neater edge. Am I supposed to caulk it now? Or is it not supposed to be a water-tight seal? It seems like the water would never get that high anyway.

 

[wjr75]

We have a slightly black ring in our skimmers and I actually use it as the fill line to know when I need to add water when our pool cover is closed. Like Dave said above they could have finished off the top a little better.

 

[ummgood]

Jamie do you need to SLAM again because you failed the OCLT or just because you see some yellow in your skimmer? Just curious...

I am beginning to think that with an SWG I need to also dose with bleach when I have a lot of people in the pool. My plan is to test every morning and use bleach if my pool isn't near the high end of the range to get it there and just learn how to use the SWG to maintain. I'll bump up the chlorine higher when the load is different.

I think what got me now is several factors but I had been letting my FC ride near the bottom of the range too often and I think at some parts of the day it might have gone under and I didn't realize it. Plus I realized recently during my SLAM and switching to a new bottle of reagent the bottle I got last year when my pool was under construction is weaker which leads me to think I might have been under the minimum at times because of that alone AND a week ago we got a wind storm through Austin and I had TONS of leaves in the pool and I was trying to get them out like a mad man but I wasn't able to keep up with it.

With all that said I am going to be more diligent to make sure the SWG keeps the pool at the high end of the range just in case and not be worried if it goes over 1 or 2 ppm. I'll dial it down when it gets 4 or 5 over and then turn it back up when I get to the top of the range. I didn't realize the pool was safe to swim in until shock level. Plus I am going to brush more often.

I am thankful my pool is new and it really is still pretty clean and I haven't let it get green. I think we at least have that going for us while we learn how our pools behave.

 

[wjr75]

I keep my pool 1 to 2 ppm above the target CYA/FC ratio. Gives you some buffer depending on the demand.

 

[JamieP]

Jamie do you need to SLAM again because you failed the OCLT or just because you see some yellow in your skimmer? Just curious...

I am beginning to think that with an SWG I need to also dose with bleach when I have a lot of people in the pool. My plan is to test every morning and use bleach if my pool isn't near the high end of the range to get it there and just learn how to use the SWG to maintain. I'll bump up the chlorine higher when the load is different.

I think what got me now is several factors but I had been letting my FC ride near the bottom of the range too often and I think at some parts of the day it might have gone under and I didn't realize it. Plus I realized recently during my SLAM and switching to a new bottle of reagent the bottle I got last year when my pool was under construction is weaker which leads me to think I might have been under the minimum at times because of that alone AND a week ago we got a wind storm through Austin and I had TONS of leaves in the pool and I was trying to get them out like a mad man but I wasn't able to keep up with it.

With all that said I am going to be more diligent to make sure the SWG keeps the pool at the high end of the range just in case and not be worried if it goes over 1 or 2 ppm. I'll dial it down when it gets 4 or 5 over and then turn it back up when I get to the top of the range. I didn't realize the pool was safe to swim in until shock level. Plus I am going to brush more often.

I am thankful my pool is new and it really is still pretty clean and I haven't let it get green. I think we at least have that going for us while we learn how our pools behave.

Hi Ummm! Welcome to my SLAM! This was just a regular SLAM with me waiting to pass my OCLT when I saw the brown in the skimmer and got paranoid about algae. It seems like I'm in the clear there though, so I'm just working diligently to pass the OCLT. I took out my returns today and scrubbed them plus inside the pipes with a bottle brush, and a small cloud of white came out of one of the pipes so I'm hoping that's the source of my problems. It's such a guessing game when there is no visible algae and the water is clear. Not to mention an emotional roller coaster every night til morning to see if you've passed -- at least for me.

Your plan to supplement with bleach for high bather load is a good one. We had a party and were at the right FC from the SWG before we started, but I used a jug of bleach to bump it up before the party, and again after we were done. This SLAM isn't related to that party though. I'm not exactly sure what all went wrong, but I must have been cutting it too close on the target levels. I think that was the result of testing error where I realized the tube I was using for FC tests was giving me a larger water sample than the Taylor tube that goes with the SampleSizer. So even though I had been getting readings of 6 for the FC, since it was a larger water sample than it should have been, the FC was likely lower, and too close to the 4 I didn't want to get under. Then when I staggered my pump run times for the SWG, I think that threw things off. But, that's just my guess, and I hope to solve the problem by targeting higher so I have a bigger buffer.

- - - Updated - - -

I keep my pool 1 to 2 ppm above the target CYA/FC ratio. Gives you some buffer depending on the demand.

Thats a very good practice, as I've come to see! I'm looking forward to passing the OCLT so I can give it a try!

 

[JamieP]

I need help!

I've been SLAMIng a clear pool since Saturday (6 full days) and it seems like my FC tests are getting worse. We have been scrubbing at least twice daily, much more in the very beginning, and dosing every 2 hours. I have a measured CYA of 80 so I have a SLAM target of 31. I was suspicious that it might be higher after hearing that for some people the CYA 50 standard doesn't have the dot disappear for them until a lower number, so I ordered the CYA standard to compare but it hasn't arrived yet. I think it should get here tomorrow.

Here is the history of my OCLTs
Cleaned filter 7/16. Began SLAM that morning.
(Dates are for the morning following the OCLT)
7/17 34.5 to 28.5 = loss of 6
7/18 40 to 32.5 = loss of 7.5
7/19 30.5 to 30 (this was suspect because my nightly addition should have had me higher than 30.5 so I kept up the SLAM)
7/20 29 to 25.5 = loss of 3.5
7/21 8pm FC=29 (dose to get to 33)
10pm FC=28.5, CC=0.5 ... Tested again with same sample and got FC=27.5
So it doesn't look like I'll be passing the OCLT tonight. Still trying to decide what to do it to before heading to bed.

Today I was targeting 33 all day (trying to help myself if my CYA is higher than I thought) and I was consistently losing about 2 FC per hour. The pool is getting warmer each day so it feels like I'm fighting a losing battle. The water is clear but has a funny smell to it in my opinion (chlorine, but something else too) especially when I smell my hands after they've been in the water. I don't recall this when we did our first SLAM last month.

I know we just have to keep at it, but is there anything else I can do? I've cleaned everything I can think of except the two poles we use to brush. I have no idea how to clean those and we need to use them to keep up with brushing for the SLAM. I let the kids swim yesterday morning when the levels were below 31, but we haven't been in again and I don't think we will until this is behind us.

What are my options for draining to lower the CYA and how would I go about doing that while trying to not let the algae get worse since if the water gets too low the skimmers won't work?

Also, there was an old Deep End post by chem geek about people in my situation (although it seems I hopefully don't have mustard algae) but I didn't know what to make of it or if there was a conclusion drawn: High CYA Levels, Shocking, Yellow/Mustard Algae

Do things sound as bad off as they seem to me, or is it just a matter of patience? It feels like I must be missing something. Please weigh in with any thoughts and/or encouragement you might have. Thank you!!!

 

[pooldv]

I am not a fan of any of those options at all except for borates. And borates don't make a big difference either. So, you have no visible algae in the pool, just some funk in the skimmer that you bleached and brushed and the water is crystal clear. I'd be willing to try letting FC drop to 12 or 15 and do another OCLT. Just to see what happens. And I would definitely be swimming in that pool! We all swam every day while SLAMing last summer with FC 25-28 and CYA at 70. FC at at shock level for your CYA is less harsh than FC at 1 ppm with no CYA. Seriously! I know it seems crazy.

Oh, the smell is most likely CCs.

 

[JamieP]

We decided to target 35 with our last dose last night, but didn't stay up to test because I wasn't thinking we'd pass the OCLT this morning. I couldn't sleep so I got up to test before sunlight. FC is at 29.5, possibly 30, so that's still a big loss overnight. Water still smells funny when I put my hand in, but CC=0 this morning.

Thanks for your input Pooldv. With the numbers I'm getting, I don't think I'd pass an OCLT even at a lower FC.

I'm going to check the skimmer again in daylight to see if there is anything in it. I'd been spraying it with diluted bleach, and a couple of times I wondered if there was a fine "dust" accumulating when I wiped it with my finger, but thought it might be leftover salt from the bleach.

 

[duraleigh]

A CYA of 70-80 makes it a little hard to SLAM but still doable. The smell is puzzling. You should be odor-free and passing the OCLT by now but you are obviously not. I can think of no other remedy but to keep at it.

There is no need to chlorinate every two hours this late in the SLAM. I would test and add twice daily.....morning and night.

I am glad you got that skimmer cleaned up.....I should have been a bit more diplomatic when I scolded the PB! . When you get a chance, post a pic and I might have an idea on a good way to seal it off.

So. stay with the SLAM. You are consuming FC which is only consumed by organics and sunlight so you are killing organics. You'll get to an endpoint soon.

 

[JamieP]

A CYA of 70-80 makes it a little hard to SLAM but still doable. The smell is puzzling. You should be odor-free and passing the OCLT by now but you are obviously not. I can think of no other remedy but to keep at it.

There is no need to chlorinate every two hours this late in the SLAM. I would test and add twice daily.....morning and night.

I am glad you got that skimmer cleaned up.....I should have been a bit more diplomatic when I scolded the PB! . When you get a chance, post a pic and I might have an idea on a good way to seal it off.

So. stay with the SLAM. You are consuming FC which is only consumed by organics and sunlight so you are killing organics. You'll get to an endpoint soon.

Thank you, Dave. I truly appreciate the support and expertise from this forum. I know I just need to stay the course, but I'm getting a little worried.

For the SLAM, it's good to know that you advise to just test and dose twice a day, but with the FC loss I'm seeing throughout the day and even overnight, how does that keep me from falling behind and not letting the algae get worse? Do I still just target 31 with each of those doses?

The smell is not noticeable when you are outside the pool or not even really when I put my nose right above it. Only when it touches part of my body. Is that from the high chlorine consuming CCs?

Thank you again for your help. I'm willing to do what it takes to clear this up (hence my attempt to help by testing every 2 hours) but I fear it's only getting worse somehow. Water temp is 87 right now and got to 94 yesterday, I think. Would using a fountain to cool help or hinder my SLAM? If it lowered the temp, it would sure make for more comfortable swimming!

 

[JamieP]

Here is a photo of one of the tidied skimmers. I'm not sure why the water appears blue in the picture while it was clear in the post above from the other day, although this was still in the shade of the morning sun and the other was in the afternoon. But now I'm worried that my water isn't as clear as it appears to the nake eye.

 

[ummgood]

How precise are you being with filling up your test tube? I would hold it to eye level and when you fill to the line make sure that the bottom of the curve in the water lines up with the line. You probably already know this but I am really anal with this stuff and I don't know if it makes that big of a difference or not.

Make sure when you add the drops from your reagent that you do it slow so a full drop can form each time. I wait a second between drops.

Also do you have newer chemicals or are they from when you started your pool? I found mine were weak when I started using a new bottle of reagent for my chlorine test and the FC level was probably 20-30% lower with the new bottle.

If you already do all this you can tell me to shove off Oh and I hated college chemistry because I would always accidentally do an extra drop from my pipette. At least with the pool it isn't as big of a deal.

- - - Updated - - -

Oh and one more thing is I always try to measure when there is no more sun out and I know my kids have been out of the pool for at least a hour or two. I think the chlorine can drop after dark battling whatever they put in there. Plus yesterday I had a ton of leaves and grass put into the water by my lawn guys and that was frustrating. My wife measured at 1 and mine had dropped to 15ppm and it was from all that stuff floating around. Thankfully she got it out.