SLAM again

straygecko

Member
Mar 10, 2023
12
Palm Coast, Florida
Pool Size
18000
Surface
Plaster
SLAMed and now having to SLAM again a couple of weeks later. Trying to figure out what went wrong and what do I need to do so I don't need to SLAM every couple of weeks.

Beginning of December had chlorine levels crash on me despite kicking SWCG to 100%. Probably due to a couple of issues. First, pool cage is getting work done and lots of screen missing so I was getting leaves in the pool. I didn't realize how many leaves got past the skimmer and pump baskets and about a third of the cartridge filter had about 1/4" thick mass of leaves covering it. And I learned a quirk of the Circupool RJ45+ SWCG - when it powers on and water in the pipes is very cold it throws an alarm and won't generate until you power it off and back on even if warmer water from the pool is pumped through the pipes. So on very cold nights when the pump kicks on in the morning it requires manual intervention to get the SWCG generating. So it didn't run for a couple of days when I thought it was running. CYA was also low and I thought I was having a salt cell problem so I started using LC and raised the CYA. Pool got hazy but not green. So I did an OCLT and had 4 loss. Started SLAM and sure wished I hadn't raised that CYA as I went through a whole lot of LC. Mid-December I got to a OCLT of 1, .5 CC and pool was crystal clear. Stopped SLAMing and let the FC drift down. Turned the SWCG back on @ 40% just over a week ago. It started raising the FC so I turned it down to 30%. First day FC dropped 0.5. Next day it dropped 2. Kicked the SWCG up to 60% and FC dropped 3. CYA had dropped to 30 and pH that had been steady at 7.5 dropped to 7.2. Pool getting hazy (not green). I did an OCLT and loss was 2.5. Been SLAMing again for 2 days. Pool is crystal clear, OCLT this morning was 0.5, CC 0.

Current chemistry:
FC 12
CC 0
pH 7.2 @ start of SLAM
TA 70
CH 375
CYA 30
SALT 3600

What went wrong the first time? OK to stop the SLAM and restart the SWCG?

TIA for your insights.
 
You need to forget the SWCG and leave it off till the water stays well above the low limit of no production. Follow through with slam again and keep slam going an extra few days before you call quits. Use LC and don't skirt FC danger levels by keeping the FC at upper target level. Since your in Florida 30 CYA may not be high enough after slam so I'd get it up to maybe 40 for sure. Make sure the reagents aren't expired.
 
It sounds like you are still battling some organic junk in there. Not sure why your cell is not generating when the water warms up, mine doesn't seem to have that problem. :scratch: Regardless, if your water temp is chilly you shouldn't be losing so much FC. My water temp is in the 50s and my cell is at like 5 or 10% (runs 24 hrs). It's possible that even though you passed that first SLAM back in Dec with an OCLT of 1 ppm, perhaps it was borderline. Or perhaps you still have growth somewhere hidden like behind a light in the niche or something.

At this point, if you're still unsure I would do another Overnight Chlorine Loss Test. It's very important to clearly pass that OCLT before chasing the SWG tech issue. Our cells cannot keep-up with algae, so I would start with the OCLT and go from there. Hope that helps.
 
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You need to forget the SWCG and leave it off till the water stays well above the low limit of no production. Follow through with slam again and keep slam going an extra few days before you call quits. Use LC and don't skirt FC danger levels by keeping the FC at upper target level. Since your in Florida 30 CYA may not be high enough after slam so I'd get it up to maybe 40 for sure. Make sure the reagents aren't expired.
SWCG has been off for both SLAMs and using LC and keeping it at SLAM level. Plan on getting CYA back up to 60 or 70 once done with the SLAM as keeping FC in the 20's with a high CYA sucks. Reagents were less than 6 months old and since last SLAM used them up now less than a month old from tftestkits. I suspect you're right about going an extra couple of days. Thanks.
 
If you know your daily FC loss I'd keep it going for atleast a week with LC after slam and do a OCLT every other day that week just to be sure you actually got a grip on the algae otherwise raising the CYA too early my turn out disastrous should you need a third slam for some reason. You also have to be certain your SWCG is actually producing what it's supposed to when you finally go back to using it.
 
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It sounds like you are still battling some organic junk in there. Not sure why your cell is not generating when the water warms up, mine doesn't seem to have that problem. :scratch: Regardless, if your water temp is chilly you shouldn't be losing so much FC. My water temp is in the 50s and my cell is at like 5 or 10% (runs 24 hrs). It's possible that even though you passed that first SLAM back in Dec with an OCLT of 1 ppm, perhaps it was borderline. Or perhaps you still have growth somewhere hidden like behind a light in the niche or something.

At this point, if you're still unsure I would do another Overnight Chlorine Loss Test. It's very important to clearly pass that OCLT before chasing the SWG tech issue. Our cells cannot keep-up with algae, so I would start with the OCLT and go from there. Hope that helps.
I read on another thread someone else having the same problem with the Circupool SWCG. I've got a 2 circuit timer coming so I can turn it on 5 minutes after the pump starts. Water is not chilly, its nice and warm (86) as we have the pool heater on swim a few times a week. But water in pipes gets cold overnight. SWCG @ 30% 12 hours a day (PoolMath says FC 2) was keeping up with the chlorine loss prior to the first SLAM. I don't see how to remove the light so I haven't gotten behind it. Been brushing everywhere else with the big brush and a smaller corner brush. I am definitely going to see a couple of days of good OCLT in a row before I stop the SLAM this time.
 
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For this slam be sure you do ALL the things 👇
*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.
 
For this slam be sure you do ALL the things 👇
*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.
I scrub everything I can, even the bottom even though my pool cleaner has scrubbers and is running 24x7 for the SLAM. I couldn't figure out how to remove the light but I looked again and saw a spot of what I thought was corrosion that was really the hole for the retaining screw. Tried to remove it and its frozen solid so no go on removing the light to scrub the niche. You made me realize I have a couple of lines that weren't getting circulation. The main drain was off to give full power to the pool cleaner and there are a couple of bubbler jets for a deep end seat that stay off. Got those both going now. Cleaning filter every other day during the SLAM whether pressure goes up or not. Thanks for the help.
 
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