4th SLAM and it is a mystery

[otter86753]

I have had to SLAM my pool three times already this summer and now have to perform a 4th. I have had to add CYA three times this summer as well. The history of the SLAMS are:

#1 My SWG flow sensor had to be replaced (understand the need for this one)
#2 FC never dropped below minimum, but there was algae in the lights and under the ladder
#3 FC never dropped below minimum and no visible algae but cloudy water
#4 will be started this afternoon. FC never dropped below minimum. Had 6 people over yesterday and checked FC immediately after they got out at 5:00 PM and FC was 4.5 with a CYA of 80 so above my minimum. My SWG and pump turn off at 8:00 PM and my FC was 4.5 this morning when I checked at 8:00 AM just before my pump and SWG turn on. There is a thin film of green on the wall by the deep end ladder. There have been palm fruit berries in the pool, but we try to keep those up with a leaf rake.

Full set of test results:

FC 4.5
CC 0
PH 7.6 (just added MA to reduce to 7.2 to start the SLAM this afternoon)
TA 80
CH 250
CYA 80
Borates 50
Temp 86

It is a mystery why I am having to SLAM so many times when I'm not dropping below the minimum FC level. I target between 6-8 and my SWG runs at 40%. I should also add that for the very first time on Saturday, I added Cellulose Fiber to my filter, but hope that didn't cause this. The irony is that I finally felt I had dialed in my chemistry after the three previous SLAMS and wanted that extra filtering so the water would look clearer at night with the lights on. Any insight is greatly appreciated.

 

[Texas Splash]

That can be frustrating, and our FB pools should ideally be easy to maintain. But I too have had a couple odd things happen this year. I also lost CYA a couple times. Don't know why. So I had to adjust. Also, we are in HOT climates that demand extra protection. Even though the Pool School - Chlorine / CYA Chart lists a "minimum" FC level, I never let mine go below the target value. The heat is just too stressful on the water. So the one thing I would suggest is to adjust your SWG output after you resolve your current water issue so that the FC never drops below your target. If you can keep it a notch or two above (7-9) that may be ideal here in August when temps are outrageous. You might find that to help resolve your recurring algae/cloudiness issue. Naturally, do what you can now to ensure any active algae is eliminated by thoroughly cleaning your pool surfaces, light niches/covers, etc. Hopefully this will help you enjoy the rest of your summer.

 

[pabeader]

With a CYA of 80, isn't the minimum more like, 6? But really should try to always stay closer to 9?

 

[Texas Splash]

Otter has a SWG, so his numbers are slightly different on the Pool School - Chlorine / CYA Chart.

 

[pabeader]

I completely missed that! And I looked for first, just to be sure. :study:

 

[YippeeSkippy]

We've had some pretty wicked storms in the area lately, I've actually had to drain some water from the pool. A first! The sheer amount of water may have altered something..... Could your CYA be a bit lower than you think?

Are you brushing the pool at least weekly?

 

[otter86753]

I am brushing and we have had storms, but I haven't had to discharge any water other than through back washing.

My CYA was tested on Saturday and it was clearly 80 (I tested four times and got 80 three times and 75ish once).

corrected typo of 90....it was 80!

 

[PAGirl]

I am brushing and we have had storms, but I haven't had to discharge any water other than through back washing.

My CYA was tested on Saturday and it was clearly 80 (I tested four times and got 90 three times and 75ish once).

If that's case, it may very well be 90.

 

[otter86753]

If that's case, it may very well be 90.

Please see that it was a typo and the tests were one 75 and three 80.

 

[ping]

Ladders in pools can be a big problem if they aren't completely cleaned of algae. Remove the ladder from the pool if possible and scrub it. You might have a water circulation problem and poor circulation around ladders will let algae grow if the ladder doesn't get scrubbed.

 

[otter86753]

The ladder is stainless steel and it does not have any algae under the three rungs at all. I brush it every couple of weeks to make sure. I have very good clockwise circulation around the entire pool. It is amazing that I have had to SLAM four times this year after never having to SLAM before.

 

[Megsyperk]

Stupid question but you're passing OCLT every time, right?


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[Megsyperk]

That can be frustrating, and our FB pools should ideally be easy to maintain. But I too have had a couple odd things happen this year. I also lost CYA a couple times. Don't know why. So I had to adjust. Also, we are in HOT climates that demand extra protection. Even though the Pool School - Chlorine / CYA Chart lists a "minimum" FC level, I never let mine go below the target value. The heat is just too stressful on the water. So the one thing I would suggest is to adjust your SWG output after you resolve your current water issue so that the FC never drops below your target. If you can keep it a notch or two above (7-9) that may be ideal here in August when temps are outrageous. You might find that to help resolve your recurring algae/cloudiness issue. Naturally, do what you can now to ensure any active algae is eliminated by thoroughly cleaning your pool surfaces, light niches/covers, etc. Hopefully this will help you enjoy the rest of your summer.

Texas Splash, what cya do you keep your pool at?


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[otter86753]

Stupid question but you're passing OCLT every time, right?


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Yes I am passing all three parts of the SLAM every time.

I might also add that we took out three queen palm trees that added minimal shade, and a neighbor MAJORLY trimmed an elm tree that took away some shade from our pool.

 

[ping]

After this SLAM is complete target the FC at 8ppm and don't let it drop below 6ppm. Something is not adding up so maybe a slight increase in the FC will help.

Another question, how long does it take to pass the OCLT each time you have had to SLAM the pool?

 

[otter86753]

Another question, how long does it take to pass the OCLT each time you have had to SLAM the pool?

The first time I don't recall. The second passed after two days and the third passed after one day.

 

[ping]

Run an OCLT tonight with the FC at 10+ and let us know the result in the morning, hopefully it is not too late already.

 

[otter86753]

I didn't see this until this morning but I did pass the OCLT last night and the water is clear. I am going to keep at Shock Level today and run another test tonight.

 

[otter86753]

I passed the OCLT again last night. Hopefully this will do away any more SLAMs.

 

[run53]

I have trouble with my CYA testing accuracy. For example, my reading of 70 could be anywhere between 60-80. So, when I SLAM, I always SLAM for a CYA of 10 more than my current CYA reading. Before I used that method, I was SLAMing, passing all 3 tests and then once FC dropped to normal levels for CYA, the cloudiness would reappear. So, if my CYA reading says 70, I SLAM to CYA 80 levels, just to be sure.

I was having similar issues as you this year (4 SLAMs), but slightly over SLAMing has cleared things up for good on the final attempt.