Pool Slam - Unsure of Next Steps

monicagrace27

Active member
Jun 8, 2021
37
Saint Francis, MN
Hey Everyone! I posted a week or so ago and am back again for some advice. I did a lot of reading about SLAMing a pool and decided to start since my pool had sat for over a year without anything being done and looked really swampy. So I followed the instructions and balanced the Ph and Alkalinity, then added CYA all based on pool math. We have a 28,000 gallon pool that we scrubbed and took as much debris as possible out before starting. Based on pool math, we added what it said we needed for chlorine and kept the levels up above 10 ppm for the past week based on test strips (I know- not reliable, but I ordered the TF-100 test after posting on this forum and still haven't received it). So, in the meantime, I brought some water to be tested at the pool store two days ago and got the following results:
FC: 11.19
Total Chlorine: 16.32
Combined Chlorine: 5.13
pH: 8.2
Alkalinity: 132
Hardness: 148
CYA: 34
Iron: .3
Phosphate: 2965
I know that you all don't think the pool store results are accurate, but I'm just trying to work with what I have at this point until the test kit comes. So, based on this, I was told to add 8 more gallons of liquid chlorine, which I did two days ago (I haven't had the water re-tested since). I guess I'm wondering what to do next... the pool went from a deep green to a light murky green/brown, but I haven't seen any real change in color or cloudiness for a couple of days now. Its been 7 days since we started and I thought we would maybe see more change by now. Should I change the sand in the filter? Just Keep adding chlorine? Add something to reduce the iron levels in case that is what is making the water murky? Sorry for the long explanation, but I am at a loss and appreciate any and all help! I also attached a current picture of the pool in case that helps.IMG_9716.jpg
 
SLAM requires several things that have to happen to make it work in a timely matter
First - keep the desired FC level constant based on your CYA - so you have CYA of 40 (rounded up) so you need to maintain a FC level of 16ppm - this should be tested every 4 hrs during day light hours.
Second - brush the walls and floor as much as possible to free up algae
Third - monitor your filter pressure and if it raises 25% above the baseline (i.e. if at 20 psi and it goes above 25 psi) then backwash it.
Keep this process going until you see your water becomes clear.
 
Don't try to do much of anything. Without testing at home frequently it's a waste of time and money. At most you could add 1-2 gallons per day just to try and keep it from getting much worse.

When did you order your TF-100?
Thanks for the reply! We just added two more gallons last night. Do you think we should do anything about the pH, or wait for the test? I ordered it last week sometime, I'm expecting it today or tomorrow.
 
SLAM requires several things that have to happen to make it work in a timely matter
First - keep the desired FC level constant based on your CYA - so you have CYA of 40 (rounded up) so you need to maintain a FC level of 16ppm - this should be tested every 4 hrs during day light hours.
Second - brush the walls and floor as much as possible to free up algae
Third - monitor your filter pressure and if it raises 25% above the baseline (i.e. if at 20 psi and it goes above 25 psi) then backwash it.
Keep this process going until you see your water becomes clear.
Thank you for the response! We have been trying to keep the chlorine up, but its hard to know exactly where it is without the test kit or without going to the pool store every day. I have been brushing daily! Should we be vacuuming too?
Also- unfortunately our pressure gauge on the filter doesn't work, so its hard to know when to backwash. Is there any sort of timeline for how often to backwash without having the working pressure gauge?
Edited to add: Is it bad to have FC too high?
 
Do you think we should do anything about the pH,
The pH is usually a simple test to do, even for the pool store. So if you are confident the pH is at least 8.0, you can use our PoolMath APP to calculate how much acid is required to lower the pH to about 7.4. Better to not go too low right now until your kit arrives.
 
The pH is usually a simple test to do, even for the pool store. So if you are confident the pH is at least 8.0, you can use our PoolMath APP to calculate how much acid is required to lower the pH to about 7.4. Better to not go too low right now until your kit arrives.
That sounds good.. We added the chlorine they recommended so I was thinking of bringing in another sample to see our levels today, maybe I will do that first to verify that they still get a pH reading of 8.2 before I add any muriatic acid. Thank you!
 
Just be sure to ignore anything they say. :)

full
 
I have been brushing daily! Should we be vacuuming too?
If you vacuum to waste that should be OK but if it is going to your sand filter then I would ensure the pressure gauge is functional so you know how much debris is being picked up.
Agree it may be hard to run to pool store every 4 hrs so just add chlorine to keep it from getting worst. Brush and wait for your test kit to really go full force with the SLAM.
 

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If you vacuum to waste that should be OK but if it is going to your sand filter then I would ensure the pressure gauge is functional so you know how much debris is being picked up.
Agree it may be hard to run to pool store every 4 hrs so just add chlorine to keep it from getting worst. Brush and wait for your test kit to really go full force with the SLAM.
Thank you for the advice! I ordered a pressure gauge on Amazon that will be here Friday, so I guess I'll know more then. And when the test kit comes. Its so hard to be patient though!
 
Hi Everyone!

I am here to post again because I just completed the test kit from tftestkits.net for the first time. The results I got were:
FC: 14
CC: 3
Hardness: 325
Alkalinity: 300
CYA: 40-45
pH: 7.3? (darker than 7.2 but lighter than 7.5)

I'm not 100% sure what these numbers should be. I am SLAMing the pool so I am thinking that my chlorine should be higher? I'm just not exactly sure based on the CYA though. Any tips for what I should do next would be greatly appreciated! Thank you!

Edited to add: I wasn't entirely sure about the alkalinity. It seemed to turn pink at 26 drops, but it was supposed to turn red so I continued adding drops and it seemed more red at 30 drops which would be 300. So I wasn't sure if dark pink would count or if it needed to be a more solid red. So alkalinity could be 260-300.
 
Great job on the test results!
A CYA of 45 means we use 50 ppm. So your SLAM level FC is 20 ppm.
The CC of 3 is interesting. One of the next times you do a FC test, do the CC again. Should be less than that.
pH is not valid with your FC above 10 ppm.
 
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Great job on the test results!
A CYA of 45 means we use 50 ppm. So your SLAM level FC is 20 ppm.
The CC of 3 is interesting. One of the next times you do a FC test, do the CC again. Should be less than that.
pH is not valid with your FC above 10 ppm.
Thank you! How long after adding chlorine (based on poolmath) to bring it up to 20 ppm should I be checking FC and CC?
Oh okay. Do I need to do anything about the alkalinity? It seems high. Or is that irrelevant right now too?
 
At the start, test FC and raise back to SLAM level every couple hours. Should be able to slow that down by Monday or Tuesday.

No need to mess with anything but FC.
 
Again - great job on using the test kit for the first time.
It is always a dauting process initially but suggest you look at these videos
Also, if you just want to practice, do the Alkalinity test again. remember that one is a 25ml sample and the color change should be to a cherry red - on my testing it goes to a pink/purple then on next drop it is cherry red. Just to give some clues to look for.
Good luck - Marty has you well covered on the SLAM process.
 
At the start, test FC and raise back to SLAM level every couple hours. Should be able to slow that down by Monday or Tuesday.

No need to mess with anything but FC.
That sounds good, thank you! At this point, I have now tested 4 times and after bringing FC up to 20 after the first test, the next results were 19 (four hours after first test and chlorine add), then 18 (overnight about 12 hours later), then 20 (in the evening about 10 hours after the last test). So over the last 10 hours during the day, the FC has held. HOWEVER, my CC is reading at 2.5 (confirmed by my husband as well). So I'm not sure why that is so high even when my FC is at shock level and holding there?
 

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