Do I need to SLAM?

offtheclock

Silver Supporter
Dec 30, 2020
292
Greenville, SC
Pool Size
13500
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
My pump broke and pool sat stagnate for 9 days With zero FC until my new Pentair VS pump was installed. Water remained clear. Got the pump running 2 full days ago and my SWG producing. Did all my tests tonight:
FC 3.5
CC .5
TA 70
Salt 3400 (Down from 4000)
CYA most likely at 10 to 0 from 40
Did have to drain around six inches of Water from all rain with boat bilge pump.
Not sure why my CYA dropped so much. Is that normal?
 
The CYA test is not very predictable when the level drops below 30 on the vile since you can't really split the gaps when looking. It doesn't work that way. That and just our own vision testing variance can make the result tough to read accurately. I'm sure the water exchange also impacted the CYA a little. Either way, it's good you caught it so that you can increase the CYA back to a reasonable level before colder temps roll in.
 
Just did a test this morning. Been raining all night.
FC .5
CC 2

what’s strange is yesterday around 5 or 6 in the evening when I tested I had only .5 cc and it’s been cloudy, cool and rainy all night. Going to add cya today. Hoping I don’t have to slam as water works perfect.
 
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Hoping I don’t have to slam as water works perfect.
That was a large FC drop for sure. If you don't start a SLAM today, I would definitely increase the FC to about 7-8 today with liquid chlorine. Give it a kick-start, then do an Overnight Chlorine Loss Test this evening if you can.
 
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Came home at lunch after swg running at 100% for five hours and FC still at .5, CC at 2.0. Water clear as can be and no signs of algae. I added 1 gallon of liquid conditioner half to skimmer and other half to pool return. Then added half gallon of 10% chlorine in front of return and got same results after 45 min. Added the other half of gallon and now I am at 2.5 FC and .5CC. I set my SWG to boost mode. Also ran to pool store and had them double check and they came back same. They also said my cya is at 50 now but I have not retested yet.

Should I run my swg later tonight than normal? It’s been cloudy here all day and is scheduled to turn off at 7pm. Also will do another FC test in morning to see if I really have a problem. Any pointers. My sons birthday party is this weekend! Thanks!
 
You're being to gentle. :) As I recommended above, you really need to add enough liquids chlorine to increase the FC to about 7-8. The SWG will not produce the FC gains you want. They are not designed to do that. Increase the FC ASAP and perform an Overnight Chlorine Loss Test this evening with SWG off. Be sure to read that OCLT page carefully. If you fail the OCLT, then you know you have algae in the water. Clear water can be deceiving. We see it all the time. The chemistry does not lie. Good luck!
 
You're being to gentle. :) As I recommended above, you really need to add enough liquids chlorine to increase the FC to about 7-8. The SWG will not produce the FC gains you want. They are not designed to do that. Increase the FC ASAP and perform an Overnight Chlorine Loss Test this evening with SWG off. Be sure to read that OCLT page carefully. If you fail the OCLT, then you know you have algae in the water. Clear water can be deceiving. We see it all the time. The chemistry does not lie. Good luck!

Okay if I have to do this i will have to get started tomorrow I ran out of light because of the clouds and there is some rain. I did go down to do another quick test and FC is still at 2.5 and CC is at .5. So it seems that’s holding. Leaving my swg run until 9 tonight in boost mode.

Hoping I don’t have to slam tomorrow as this pool care thing still makes me nervous and seems to be consuming me. I did pick up three more gallons of 10% Chlorine just in case while at pool store.

I can also do my own cya test tomorrow to determine proper slam level since that will give my liquid conditioner time to mix.
 
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I wouldn't be surprised if a SLAM Process is needed at some point because your FC has been low several times, but don't go right into it just yet. Get come chlorine tomorrow and then do the Overnight Chlorine Loss Test tomorrow evening first. Let's see what your FC consumption is with no sunlight first.
 
@Texas Splash well I am not sure what to. Just tested this morning at 7am and my FC dropped to .5 from 2.5 but my CC is 0. Tested twice. Going to leave my swg in boost and if I need to start slam I can come home at lunch. Please let me know what you think.
 
well I am not sure what to. Just tested this morning at 7am and my FC dropped to .5 from 2.5 but my CC is 0
Hey OTC !!! If you fail any of the 3 parts, you fail.

clear water
CCs above .5
OCLT over 1.

Loosing 2 FC overnight means it’s SLAM time. But having clear water usually means it will be a much easier battle. So there is that. :)
 
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I would agree.

full
 
My motto: Hesitation and indecision can be killers. I would rather slam and not need it than the other way around. Cheaper and easier to burn a bit of chlorine for a couple days instead of a week or two weeks of full blown slam.

The experts here are very good! Trust them!
 
My motto: Hesitation and indecision can be killers. I would rather slam and not need it than the other way around. Cheaper and easier to burn a bit of chlorine for a couple days instead of a week or two weeks of full blown slam.

The experts here are very good! Trust them!
Headed home at lunch to start.
 
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At home. Here’s where I am at:
1.5 FC
0CC
55CYA
Running swg in boost still

Slam level 20 so I added 2 gallons of Chlorine that’s 12.5% hypochlorite and brushed for 15 min. Pool pump running at 3000Rpm. Water is still clear.
 
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Water is still clear
Should be much easier with it mostly holding FC. So you’ve basically skipped right to day 5-7 from the get go. Brush and vac like normal just because. Maintain the FC as often as possible. Leave no stone unturned and when you have a few mins, go on a full blown algae treasure hunt. All up in the skimmer, ladder, lights, auto fill, etc. (y)
 
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Very grateful for yalls help. I waited about 40 min after adding 2 gallons of chlorine and my FC was at 11. I was hesitant to add more because I was thinking it was still mixing because I had to get back to work. What should I expect or do when I get home at 530pm? If FC is still at 11 I stand by or raise, if FC has dropped do I try to raise it to 20 still?
 
What should I expect or do when I get home at 530pm? If FC is still at 11 I stand by or raise, if FC has dropped do I try to raise it to 20 still?
Since you listed a CYA of 55 (we round up to 60), your SLAM FC level is "24". So when you get back home, increase it back to 24 and ty to keep it in that area until bed. Tomorrow - repeat. :)
 
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Since you listed a CYA of 55 (we round up to 60), your SLAM FC level is "24". So when you get back home, increase it back to 24 and ty to keep it in that area until bed. Tomorrow - repeat. :)
10-4. I should perform a overnight chlorine loss test each night/morning as well? Maybe I will get lucky and wake up tomorrow to a stable FC from the night befores test and I can relax.
 
I waited about 40 min after adding 2 gallons of chlorine and my FC was at 11
What kinda chlorine are you adding ? 7% will get you the 11 FC that you saw. 10% should be 15 FC. Unless the 10% is old / degraded down to 7%. Either way you need considerably more to hit 24. Keep at it. You got this. (y)
 
I should perform a overnight chlorine loss test each night/morning as well?
I would save the OCLT for the last of the passing 3 criteria. If your CCs are low and the water crystal clear, then sure, you can do an OCLT.
 

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