Return of the Mustard Algae!

[SchubeyDew]

It’s that time of year again, where we are opening up our pools and trying to get everything right. Or in my case, living in Florida, trying to make seasonal adjustments as I never close my pool.
I have had this pool for three years and this is the second year in a row that I have had mustard algae. The first year there was no issue. Last year, I had a hard time determining if it was pollen or mustard algae for a while but eventually determined that since it was more in the corners of the pool and shaded areas it was most likely MA. I followed the SLAM protocol followed by the MA FC shock using liquid bleach. Followed up with regular brushing and vacuuming and the problem went away. Had no issues for the rest of the season or all winter. I attributed the MA to me not keeping on top of seasonal SWG chlorine level percentage adjustments and it getting down to a FC level of 2 or maybe less, IIRC. So this year, I made sure to bump up the chlorine percentage early and it seemed to be maintaining at 5.5 and 60-70 for CYA. But the yellow returned. It’s been an extremely high pollen year and the chlorine level seemed to be maintaining so until I brushed today and noticed my chlorine level had dropped to 3.5 I thought it was pollen.
My question is this: How long can MA stay in hidden places to come back and haunt you? Long enough to not show up for almost a year and then come back? I’m asking because I did not scour every book and cranny, although I did get most areas with a small brush. I’m already starting the SLAM process but I’m very curious why I would get MA two years in a row at about the same time of year. In three years of using the TFP method these two instances are the only times I’ve ever had issues.
Today’s testing results were as follows:

PH: 8.3
Chlorine: 3.5
CYA: 60
TA: 120 (this has been rising over the last few tests from 90-100-120 despite adding acid)
CH-not tested as the bottle exploded but has been maintaining at 350.

Prior test about 9 days ago, was:

PH: 8.1
Chlorine: 5.5
CYA: 60
TA: 100
CH: 350
Salt: 3600

Side note, I do always seem to be chasing PH and TA down.

 

[proavia]

Chances are your chlorine has dipped below minimum for your CYA.
Set your SWG to produce to maintain high side of the target range.

In Florida, you would be better served with a CYA of 70 once your SLAM is complete.

Also, be a bit more proactive in keeping your pH in the 7's
Actually, set up PoolMath to track CSI and keep CSI in the 0.00 to -0.30 (negative 0.30) range to minimize scaling in your SWG.

9 days between testing is a bit too long - even for a SWG pool.

 

[SchubeyDew]

Chances are your chlorine has dipped below minimum for your CYA.
Set your SWG to produce to maintain high side of the target range.

In Florida, you would be better served with a CYA of 70 once your SLAM is complete. -CYA of 70 is my target but it has usually dropped to 60 by the time a week has gone by. Would you still recommend 70 or perhaps 75 or 80?

Also, be a bit more proactive in keeping your pH in the 7's- Do you think the pH is a contributing factor to the algae or is this just an FYI?
Actually, set up PoolMath to track CSI and keep CSI in the 0.00 to -0.30 (negative 0.30) range to minimize scaling in your SWG.- Never heard of CSI before? What is this?

9 days between testing is a bit too long - even for a SWG pool.- I agree with you but sometimes life gets busy.

Thanks for your thoughts!

 

[proavia]

"Borrowed" from a post by @mknauss - thanks Marty!

After you have passed all 3 SLAM criteria, follow the 24 hours at mustard algae SLAM levels and then follow the mustard algae target levels for the next several weeks - these mustard algae target levels are 15% of your CYA level.

Chlorine/CYA Chart

EDIT: You will find a simplified and standardized version of this chart at Pool School, Chlorine / CYA Chart. Chlorine/CYA Chart by Chemgeek FC = Free Chlorine in parts-per-million (ppm) CYA = Cyanuric Acid in parts-per-million (ppm) CYA ........... Min FC3 ..... Target FC ...... Yel/Mstrd...

www.troublefreepool.com

 

[Bperry]

So this year, I made sure to bump up the chlorine percentage early and it seemed to be maintaining at 5.5 and 60-70 for CYA. and TA down.

5.5 is close to the bottom end of recommended FC. Sounds like you need to run closer to the upper end.

 

[SchubeyDew]

5.5 is close to the bottom end of recommended FC. Sounds like you need to run closer to the upper end.

I wondered when the previous commenter alluded to this. I’ve been using this TFP chart that I printed out 3yrs ago:


It suggests 3 as minimum and 4 as a target for a CYA of 60 and 3-5 for a CYA of 70. So I thought I was on the high end. After your comment I see that they revised it to this:



According to this, 3 is minimum but target has been updated to a much higher “Target Range” as opposed to “Target” on the original chart. Looks like my new target should be around 8.

 

[reggiehammond]

Looks like my new target should be around 8.

Your new target should be to never, ever get remotely close to minimum. There's no reason to micro-manage FC to be low; just find somewhere comfortably high enough to never get close to min. For me, if my min is 3, I try to never see less than 10 once the water is warm, sun is out, and the SWCG is cranking.

With that said - I don't see any evidence of mustard algae in your pool. Can you share how you believe you have that fairly rare condition? Your skimmer photo shows more evidence of iron staining than any algae.

 

[mknauss]

If you have mustard algae issues, you should use 15% of your CYA level as your minimum FC level. Target 20% of CYA.

 

[SchubeyDew]

Your new target should be to never, ever get remotely close to minimum. There's no reason to micro-manage FC to be low; just find somewhere comfortably high enough to never get close to min. For me, if my min is 3, I try to never see less than 10 once the water is warm, sun is out, and the SWCG is cranking.

With that said - I don't see any evidence of mustard algae in your pool. Can you share how you believe you have that fairly rare condition? Your skimmer photo shows more evidence of iron staining than any algae.

Not sure I understand your logic here. You’re saying that you would never drop below more than 3x the minimum level? I do agree that having it on the higher side is best, especially in season, and according to the old chart, I was. But the new chart, while showing the minimum as the same provides a much higher target range. I think it’s worth noting that I’ve had two occurrences in three years with those near minimum levels, so I don’t see a need to go as high as ten.
As for my thought process on the mustard algae, I went into detail on how I came to that conclusion in the original post. But I realize the picture of the pool itself doesn’t quite show it because of the lighting. That’s why I also showed the picture of the skimmer, which has a yellow substance that easily brushes away. Iron tends to be red/orange and mineral deposits do not wipe off with a swipe of your fingers. The only other indicator that I would add to the original post is that while brushing, a large amount of yellow clouds were brushed up and it had only been a few days since the last vacuuming so it seems unlikely that it would be pollen.

 

[SchubeyDew]

If you have mustard algae issues, you should use 15% of your CYA level as your minimum FC level. Target 20% of CYA.

Just so I’m understanding this correctly, SLAM, then bring SLAM level to mustard algae level for 24hrs, and then after that, maintain 20% of CYA for a few weeks, which should be 12-14 if CYA is 60-70. Does that add up?

 

[SchubeyDew]

Did some additional maintenance today and I believe I have found the culprit who has been causing the mustard algae to return- it’s me. I pulled my cartridge filter out and it was in dire need of a good cleaning. The Salt cell also needs a good cleaning, probably in part because of me allowing pH to creep up too often. Add to that that my chlorine levels, which I thought were good were actually on the low side according to the new chart. Or, in short, I need to keep up with my maintenance better. My old chlorine pool was very labor intensive and the SWG has lulled me into a false sense of security. The SWG allows you to keep things much more on cruise control and it’s easy to ignore regular maintenance.

 

[kellyfair]

Hello, fellow Floridian. I’m here to encourage you to join #TeamRunHot. Since you are safe to swim anywhere between the minimum for your CYA and SLAM, you will save yourself a lot of pain if you dial your maintenance FC up. Target range is fine, but what happens when you neglect to test for a few days and a storm drops a bunch of leaves and yuck into your pool, or you have a bunch of people in the pool and they are all slathered in sunscreen? Or the power goes out for a few hours and you aren’t generating as much FC as you think you are? This is an even bigger concern if you go a long time between testing.

I strive for the top of target range, or even a point or two higher. And if the scenarios above happen, I’ll chuck a little extra chlorine in so I don’t have to rely on the SWCG to make up for a big deficit.

I just tested so I’m running at 7 FC and 50 CYA (I add CYA in steps with days in between so I don’t overshoot). I just added enough CYA to get me up to 70 and I’ll be aiming for 10-12 FC, or even a bit higher since I’m going to be out of town for a bit and want to guard against unforeseen circumstances.

Also, as said by others, try to test more frequently. And definitely do regularly check your filter.

 

[SchubeyDew]

Hello, fellow Floridian. I’m here to encourage you to join #TeamRunHot. Since you are safe to swim anywhere between the minimum for your CYA and SLAM, you will save yourself a lot of pain if you dial your maintenance FC up. Target range is fine, but what happens when you neglect to test for a few days and a storm drops a bunch of leaves and yuck into your pool, or you have a bunch of people in the pool and they are all slathered in sunscreen? Or the power goes out for a few hours and you aren’t generating as much FC as you think you are? This is an even bigger concern if you go a long time between testing.

I strive for the top of target range, or even a point or two higher. And if the scenarios above happen, I’ll chuck a little extra chlorine in so I don’t have to rely on the SWCG to make up for a big deficit.

I just tested so I’m running at 7 FC and 50 CYA (I add CYA in steps with days in between so I don’t overshoot). I just added enough CYA to get me up to 70 and I’ll be aiming for 10-12 FC, or even a bit higher since I’m going to be out of town for a bit and want to guard against unforeseen circumstances.

Also, as said by others, try to test more frequently. And definitely do regularly check your filter.

Hey Kelly, I appreciate your input. I am curious about something with your setup. Is your SWG maxed out? To drop from 10-12 to 7 is quite a bit between testing. I adjust my SWG percentage and run time seasonally so that I rarely have to add chlorine to maintain levels week to week. In the winter I can get away with 50% and about 4hrs runtime. Summertime I’m more like 90% and 6-7hrs runtime. I will be increasing my level after all seeing the new chart and hearing everyone’s experiences so we’ll see what it will take to maintain a higher level.
On the maintenance note, I will try to be more diligent with my testing and I have turned on reminders in PoolMath to help.

 

[kellyfair]

Nope, not maxed. it’s running at about 25% but I run 24/7. Once the CYA is fully dissolved I’ll be able to dial it down.

Establish the level you want with liquid chlorine. Then just run your SWCG enough to replace daily loss. Of course, daily loss varies depending on a whole bunch of stuff, that’s why regular testing is important.

Alexa and Siri are also good for reminders, although they both can be a little condescending!

 

[Bperry]

Hey Kelly, I appreciate your input. I am curious about something with your setup. Is your SWG maxed out? To drop from 10-12 to 7 is quite a bit between testing. I adjust my SWG percentage and run time seasonally so that I rarely have to add chlorine to maintain levels week to week. In the winter I can get away with 50% and about 4hrs runtime. Summertime I’m more like 90% and 6-7hrs runtime. I will be increasing my level after all seeing the new chart and hearing everyone’s experiences so we’ll see what it will take to maintain a higher level.
On the maintenance note, I will try to be more diligent with my testing and I have turned on reminders in PoolMath to help.

Thats helpful info. 4 hours of runtime leaves 20 hours each day with no chlorine generation. The levels can drop quite a bit before the SWG turns back on. That may be part of your issue.

Consider running longer at lower percentage to keep the FC level from swinging so much. If you have a variabke speed pump you can often run 24x7 at low speed for less money than part of the day at full speed.

 

[SchubeyDew]

Thats helpful info. 4 hours of runtime leaves 20 hours each day with no chlorine generation. The levels can drop quite a bit before the SWG turns back on. That may be part of your issue.

Consider running longer at lower percentage to keep the FC level from swinging so much. If you have a variabke speed pump you can often run 24x7 at low speed for less money than part of the day at full speed.

That would be one alternative, but not a very energy efficient one. I do have a variable speed pump and have it running at a lower setting most of the time. From my reading on here the recommended chlorine levels are lower for a SWG vs a pool where chlorine is added manually. Presumably because daily chlorine addition minimizes swings in chlorine levels. Even in my pool’s current condition, it only dropped from 5.5-3.5 in a week and a half period. I think the better solution is to maintain a higher chlorine level so that when there are seasonal swings it has a lot more room to drop than it currently has and it doesn’t needlessly increase my energy bills.

 

[kellyfair]

I’m confused. Are you running your pump for only the hours of the day that you are running your SWCG? Or are you running the pump 24/7 and the SWCG for a few hours a day?

Not seeing how running the pump at a low speed all the time and the SWCG at a higher % for 4-5 hours is noticeably more energy efficient than running pump at a low speed all the time and running SWCG longer at a lower % for more hours.

@Newdude is also running 24/7.

 

[SchubeyDew]

I’m confused. Are you running your pump for only the hours of the day that you are running your SWCG? Or are you running the pump 24/7 and the SWCG for a few hours a day?

Not seeing how running the pump at a low speed all the time and the SWCG at a higher % for 4-5 hours is noticeably more energy efficient than running pump at a low speed all the time and running SWCG longer at a lower % for more hours.

@Newdude is also running 24/7.

I’m only running the pump when the SWCG is running. If you search the forum for pump run times, the general consensus on here is that you don’t need to run your water through “X” number of times a day. The pool chemistry is what keeps the pool nice, not a certain amount of runtime or water turnover.
I should also note that there aren’t any sources of debris to keep up with.

 

[kellyfair]

Ah. Ok. I don’t think any of us that run longer are trying to hit a certain turnover rate - we just like keeping the water moving, clearing pollen, bugs and other floating stuff off the surface, and maintaining a steady FC rate.

But you do you! Hopefully now that you have the current recommendations for CYA and target FC, and recognize the need for more frequent testing and maintenance, you can avoid future algae blooms.

 

[SchubeyDew]

Ah. Ok. I don’t think any of us that run longer are trying to hit a certain turnover rate - we just like keeping the water moving, clearing pollen, bugs and other floating stuff off the surface, and maintaining a steady FC rate.

But you do you! Hopefully now that you have the current recommendations for CYA and target FC, and recognize the need for more frequent testing and maintenance, you can avoid future algae blooms.

Now that you mention it, I can see longer run times during high pollen season. Thanks for your insight!