Is it time to SLAM?

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TroubleFreePat

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Jun 5, 2013
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Philadelphia, PA
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Fiberglass
Chlorine
Salt Water Generator
Our FC dropped to 0 this past weekend. I was out of town and family came to use the pool. They left our auto-cover open most of the weekend, and I don't usually have our SWG running high enough to cover that situation. We only open the cover when using the pool, so our SWG is dialed in for that situation.

I brought FC back up, but in the mean time, the water clouded. So I assume it's time to slam.

Last night, I did an overnight FC loss test. Water showed an FC of 5.5 around 8:30pm. Tested again this morning at 8:30am and we're down to 3.0. So we're just over the 1ppm threshold from the overnight test. Should I wait a day or two and see how things go? The water has already started to clear up a bit, but still not the crystal clear I'm used to.

Also I noticed the SLAM / shock level chart says 24PPM, while Pool Math shows 20PPM for shock. Which is it (Knowing that a 4PPM difference at this point isn't a big deal. . .)

Here's my full test results -

FC 3
CC <0.5
pH 7.2
CYA 50 (Was working on this before I went away. . .)
TA 80
CH 230
 
TroubleFreePat said:
Our FC dropped to 0 this past weekend. I was out of town and family came to use the pool. They left our auto-cover open most of the weekend, and I don't usually have our SWG running high enough to cover that situation. We only open the cover when using the pool, so our SWG is dialed in for that situation.

I brought FC back up, but in the mean time, the water clouded. So I assume it's time to slam.

Last night, I did an overnight FC loss test. Water showed an FC of 5.5 around 8:30pm. Tested again this morning at 8:30am and we're down to 3.0. So we're just over the 1ppm threshold from the overnight test. Should I wait a day or two and see how things go? The water has already started to clear up a bit, but still not the crystal clear I'm used to.

Also I noticed the SLAM / shock level chart says 24PPM, while Pool Math shows 20PPM for shock. Which is it (Knowing that a 4PPM difference at this point isn't a big deal. . .)

Here's my full test results -

FC 3
CC <0.5
pH 7.2
CYA 50 (Was working on this before I went away. . .)
TA 80
CH 230
Click to expand...
Seeing that you failed an OCLT (a 1.5 loss from 5.5 is almost a 25% drop), and that your FC is still too low for your CYA you should SLAM.

That's a good observation you made on the shock levels, I would go with the 24ppm to be safe & PM a mod to give them the heads up on the shock level discrepancy.

Dom
 
jaduck said:
I would recommend a SLAM and it should be a short one. I'm getting 20 on both the the chart and pool math for a 50 CYA SLAM.
Click to expand...

I was looking at the SWG pool chart and somehow read 50 instead of 60 for CYA. So I'm not even on the chart. . . Looks like shock values are the same for both SWG and non-SWG, so 20 it is. Thanks.

SLAMing to commence as soon as I hit Home Depot for bleach. I'll let you know how it goes.
 
Hi Pat, the chart says 24ppm at a CYA level of 60 for SWG. If your CYA is actually 50, then 20ppm is your goal.

The 2.5 loss overnight indicates it was attacking something. I would think if you bring it up to 20ppm and check again in the morning, you might be able to whip the outbreak and should be fine.
That is if your overnight loss is less than 1.

Hopefully you can get by with a mini slam :D
 
Roger on the pump 24/7 - did see that. I missed the brushing of the pool, so thanks. How often do you guys recommend, or is it really a one-time thing during the process to knock down anything "living" on the sides (And bottom?)

I also re-read a few posts and see I need to MAINTAIN 20PPM (That part was obvious to me, but that also means I probably need to overshoot 20PPM initially as FC might get eaten up quickly.) Since I'm only losing 1.5PPM overnight, I assume this won't really be the case, but sounds like shooting for 24PPM might not be a bad place to start so I can make sure I'm keeping at 20PPM.
 
Put it this way, if you maintain 20 ppm and you fall below, this is bad, if you maintain anything above 20 ppm you may waste some chlorine. The more you go over 20 ppm the more chlorine you waste. 20 - 24 sounds good to me, just make sure you never go below 20...Algae starts wining the race below 20 ppm.
 

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Sounds good. I just dumped my chlorine in (Good news is I was still at 3ppm since 8:30am this morning; so no lose in five hours.) Hoping this is definitely a mini SLAM.

I have my pump running on high and will leave it there until all is clear. I'll check in an hour and see how close my math/dose was (Also a good test because I've heard different numbers for how many gallons my pool is - I did my math on the lowest number of gallons - can always add more bleach in an hour!)
 
Hit that mark pretty well. Checked FC about 1.5 hours after adding bleach and I'm at 22.5ppm.

Also helped me further fact check how many gallons I THINK my pool is. When it was installed, installers said about 10k gallons. Leisure's own literature at the time stated 14,300 gallons. I couldn't see how this could be right based on how much water I put in the pool when installed, as well as its dimensions.

I FINALLY got hooked up with a guy at Leisure whose job it was to literally (That particular week) fill and empty pools to determine how many gallons they held. He surmised that the previous owners/management simply took the dimensions and multiplied length x width x depth (At the deepest point) and never took in to account curves, steps, benches, etc. He agreed with me that my pool was about 8500 gallons full.

Based on this exercise today, my pool performed as if it were at 8000 gallon pool, so pretty close. Good to know.

I'll let you guys know how it goes overnight. We have an auto-cover, which I'm keeping closed, so I'm hopefully the FC stays put; I'll check it again this evening.
 
So with the cover on all day (Thus no sun), I went from 22.5ppm at 1:30pm to 20.5ppm at 8:00pm.

I'm going to bump it back up to 22ppm as I'm going to be out for a while, then check it again overnight. I am leaving the cover off for the night since there's no sun and it can't hurt.
 
So at 8:00pm, I added enough chlorine to take the pool to 22ppm. At 3:30am, I was down to 21ppm. At 8:50am, I'm down to 20ppm. The sun is just now starting to hit the pool.

Do I bring the fc back up to 21-22 and wait and see? Should I cover the pool again since the sun will be on it now?

Doesn't seem like the water has cleared at all. It's just ever so slightly cloudy and I can tell it's off. I could still clearly see a leaf on the bottom, but it's not the normal crystal clear.
 
Keep doing what you are doing...sounds like you are doing a great job! Remember to clean your filter when the pressure rises 20-25%. You need to pass three objectives: CC = 0.5 or less (check), pass the OCLT (almost a check), crystal clear water (getting there).

Yes, you can bring the FC back to 22 or so...
 
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