Algae in 8ppm FC?

pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Most are pressure fit and get bent a certain way to pop out the molded pins that hold them in place. Every inch being suspect of course all up in there, but particularly the foam that makes the door float at the top of it. Some folks found theirs all blacked up at the beginning of the season.

@Texas Splash might have ideas
I guess I can just assume it’s nasty and scrub the heck out of it without taking it off to confirm anything.
 

pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Well, I guess I have more work to do. I did not pass OCLT. Lost 3ppm (18 to 15) last night. I’ll get at scrubbing the weir door and I’m going to open up the filter housing today and clean the cartridge and see if anything is going on in there. Not sure if I see much point in trying to maintain SLAM level of FC until I find whats causing this. The water appears clear but the small growth seems to indicate there is indeed a problem. I’ll keep the chlorine elevated in the mean time and then SLAM it again once I figure this out. Ugh - so much for a quick resolution.
 

Newdude

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Jun 16, 2019
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Not sure if I see much point in trying to maintain SLAM level of FC until I find whats causing this
I get the frustration. I do. But think clearly that you certainly don’t want it getting away from you and getting worse, whatever it is. Spinning your wheels in the meantime is a necessary evil. (y)
 

Texas Splash

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Aside from the light question, it's been a while since I posted on your thread. So let's recap some algae basics in case the obvious was not mentioned earlier:
- Consistent testing is paramount. Water sample from same location, reagent droplet sizes etc. Reagents fresh?
- Pump running 24/7 during SLAM, so the water should've been mixed really well.
- As long as the CYA test is accurate, then you would have the proper FC level to kill algae. Algae cannot survive in properly chlorinated water.
- If you have a main drain, be sure to check under the cover.
- You already mentioned the skimmer and weir door

I don't think you have much else in your FG pool other than the surfaces itself. Lights should be N/A.

Hang in there!
 

pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Aside from the light question, it's been a while since I posted on your thread. So let's recap some algae basics in case the obvious was not mentioned earlier:
- Consistent testing is paramount. Water sample from same location, reagent droplet sizes etc. Reagents fresh?
- Pump running 24/7 during SLAM, so the water should've been mixed really well.
- As long as the CYA test is accurate, then you would have the proper FC level to kill algae. Algae cannot survive in properly chlorinated water.
- If you have a main drain, be sure to check under the cover.
- You already mentioned the skimmer and weir door

I don't think you have much else in your FG pool other than the surfaces itself. Lights should be N/A.

Hang in there!
I believe I’ve done all of the above, but after I clean the filter and check the weir door today I will start again, making sure that all of the above are in place. I have no main drain. Thanks.
 

pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Well, today was frustrating. Yesterday I took the filter housing apart and the filter was pretty dirty, but I didn't think it was algae. Maybe dead algae but nothing green. Sprayed off the filter and it looked pretty good. I also looked at the weir door. Got down in the skimmer with a mirror and everything behind the door was clean. So I buttoned everything up and hoped I'd be able to pass an OCLT. I did not. Maybe a summary of what I've done will help, but I'm thinking I'll just SLAM it again and see how it goes.

I started by SLAM'ing the water on Sunday and when I did my OCLT, my chlorine went from 35 to 24 overnight. Wasn't feeling it so on Monday I just turned on the SWG at 100% and the pool went from 22 to 18 over the course of the day. Not SLAM level, but some significant chlorine. Hoping maybe things were over, I did an OCLT and did not pass. Went from 18 to 15 overnight. Yesterday I just had the SWG on normal and the chlorine stayed at 18. I did my OCLT and did not pass, but at this point, I was hoping maybe the reagents were the problem. I ran out of the liquid after a couple drops in the morning and felt that I could not rely on the comparison of a test using different bottles of the liquid. So I left things alone except now I'm at Tuesday and I cleaned the filter and checked the weir door. Did my OCLT last night and it went from 12.5 to 11. Unfortunately, I also see just a very small amount of algae in the same spot. Much much smaller, but not gone.

Obviously, I should have kept SLAM'ing. At this point, I think I've done all I can besides one more SLAM. I'm going to go brush everything down one more time, brush the bottom with my brush in combination with the robot and then throw in the chlorine. I may be wrong, but I feel like I'm getting closer, just that my starting and stopping is prolonging the process.
 
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pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Mostly using the SWG. Wouldn’t call it maintaining SLAM level because at my CYA, I should be around 24. But, the SWG has been keeping me in double digits as I puttz around with this. I use LC when I get serious, and shut the SWG down.
 

Mdragger88

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Jun 1, 2018
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I agree - time to get serious & just get it done ✅
kill it no GIF by Rooster Teeth

But in the long run (bigger picture) after SLAM Process is complete address the possibility of poor circulation in that area perhaps leading to lower fc levels there. Or the cya being a little low may have lead to dips in fc throughout the day at some point during the heat of the summer (it may not be an issue going forward if your weather is starting to change now but it may very likely have happened in the past) Or perhaps a combo of both.
Slam on! 😁
 
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pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
I agree - time to get serious & just get it done ✅
kill it no GIF by Rooster Teeth

But in the long run (bigger picture) after SLAM Process is complete address the possibility of poor circulation in that area perhaps leading to lower fc levels there. Or the cya being a little low may have lead to dips in fc throughout the day at some point during the heat of the summer (it may not be an issue going forward if your weather is starting to change now but it may very likely have happened in the past) Or perhaps a combo of both.
Slam on! 😁
In thinking this through, I agree with your analysis. I've been running my pump 24/7 at a low speed. I've also had my SWG on a low setting, which seemed to work fine (but obviously did not). However, I'm thinking in the future, I'll probably set my pump to run at a higher speed for a few (maybe several) hours during the day to get the circulation up and set the SWG higher. That will require that I shut the pump off or accept some pretty high chlorine levels, but I'll figure that out. This occurred to me on the first day of the SLAM where I was pouring LC in the pool and barely keeping is above 20. Some of that may have been algae, but I'm pretty sure the sun was the major factor. Either way, the SWG at 30% was likely not keeping up. That's my best guess at this point.

Anyway, I dumped a gal of chlorine in the pool tonight and will restart in the morning. The gal got me back over 20 but I'll shoot for 25 all day tomorrow and see how that goes.
 
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pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
One question about the SLAM and the OCLT. Is the OCLT accurate at that level of chlorine? If I'm at 24+ at sunset, aren't I going to lose some of that just because it's to high of a concentration? Said another way, if I'm at all over the recommended SLAM level, the CYA is at capacity plus. Aren't I going to lose anything over capacity even with the sun down?
 

mknauss

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Aren't I going to lose anything over capacity even with the sun down?
No. If you have no organics for the chlorine to consume, the only other thing that reduces FC is UV.

At elevated FC levels, testing error is the only variations you see.
 

pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Just a quick update. Been SLAM'in. Failed the OCLT last night. Feeling optimistic going into tonight's OCLT. There was no visible algae today and chlorine usage seemed less - even though it was sunny today. We'll see what morning (pre-dawn of course) brings. Note to future SLAM'ers - count slow. With sleep in my eyes and feeling a little groggy, I wasn't sure I counted correctly and had to restart the test. Now, I count in groups of 10 and focus. As a retired person, getting up before the sun ain't no fun.
 

pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Good morning. As hoped and kind of suspected, I passed the OCLT this morning. This has been an interesting experience. I’m still bewildered that this happened, but I have nothing else to work with except the hypothesis that my circulation may not be good in certain areas of the pool and/or, the low setting on the SWG wasn’t enough to keep up on some very sunny days (maybe a high use day also). So, that’s what I’ll be working with.

For now, the season is coming to a close here in Michigan. I’ll let the chlorine drift down a bit from SLAM level, just because I feel better about swimming in lower levels of chlorine than SLAM level, and work on balancing everything out in preparation for closing. After this weekend, there won’t be much swimming, so I’ll be able to keep the chlorine level pretty high until winter close, just to be safe. This will be my first year of closing on my own. I hope the rest of my posts this year are about that.

Thank you for the help and discussion as I worked through this. Certainly learned a few things.
 

pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Well, that was short lived. It rained pretty heavily last night and I woke up to what I think is algae in the same spot as before. Given the lateness of the season and the fact that I’ll probably be draining my pool soon (see below), I’m pretty much just going to live with it. I’ll do another OCLT tonight just to see what that indicates.

 
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Mdragger88

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Not to borrow trouble but … I would have the pool builder also pressure test all the pipes - there could be a leak/crack somewhere which caused settling/washout that contributed to the shell crack. Maybe put a sock on your returns for a day & see if u catch anything to rule out sediment ending up in your lines. Better safe than sorry since your warranty only lasts so long.
 
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pb4uswim

Well-known member
Jul 23, 2020
328
Michigan
Just thought I’d throw a couple pictures here in case it helps identify what I’m dealing with.

A27F05A2-E59C-4B9D-8EB0-E1B290AB4B93.jpegE5BEAC0C-8560-4241-90E4-72DFD488A5D9.jpeg
Obviously, its hard to get good pictures. The interesting thing is that this batch appeared the morning after the storm and has not changed since. If it were algae, wouldn’t it have grown? I didn’t touch it, or the pool in general for a couple days just to see what it would do.

Also, just checked the chlorine and I’m at 8ppm in the middle of a sunny day.
 

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