Questions before first SLAM

stillios

Member
Apr 22, 2021
19
Columbus, OH
We just moved into a new house with a pool 2 weeks ago, and we have never owned a pool before. Until last Thursday, a pool service company had been maintaining the pool weekly. I noticed after they left on Thursday that the pool appeared a bit dull, but I'm not a pool expert, and I thought the chlorine was just doing its thing. On Friday the kids said it looked "like the ocean" underwater with their goggles on. Not Maui ocean, more like Maryland ocean (what they are used to). We decided it was time to break out the water testing kit I had ordered and dive into learning about pool chemistry. Our conclusion was that the CYA was so high that the FC wasn't working (not sure of proper semantics here). The CYA was over 100, so I can't be very precise, but I would estimate around 130. The pool service people were simply dumping in more and more liquid chlorine every week and putting six 3-inch tablets in the chlorinator (I think that's what it is called) while CYA accumulated unchecked.

Here are the test results from Saturday night:
FC -- 11.0
pH -- 7.5
TA -- 100
CH -- 125
CYA -- 130 (roughly)

We read a lot of stuff about CYA, watched Youtube videos about pool equipment, and decided to drain 15 inches of water on Sunday morning. (We were scared to take out too much water at once because some articles/videos talked about pools caving in and such.) We filled it back up and let the new water circulate overnight. On Monday morning we had:
FC -- 10.0
pH -- 7.5
CYA -- 95

We drained and added another 15 inches on Monday. This morning we had:
FC -- 6.5
pH -- 7.8
TA -- 70
CYA -- 65

We are draining and adding water again once more today to lower the CYA as much as possible since we've committed to this process. We have had tablets in the chlorinator this whole time, and I know that builds up CYA. We have 13 gallons of liquid chlorine (from the pool store, 10%) on hand right now, along with soda ash and dry acid to adjust pH as needed. We haven't used any of this stuff before. My plan right now is to test the water again in the morning and add the SLAM amount of liquid chlorine recommended by the PoolMath app. The pool is looking kind of green with some visible yuckiness spreading on the floor. Based on what I've read, it seems like we'll need to test and add more liquid chlorine throughout the day. Are we on the right track here? Does my plan seem okay? Should we turn off the chlorinator? How long should I wait before adjust the pH, if necessary? Please give any advice you have!
 

cowboycasey

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GREAT job taking control of your pool and welcome to TFP.. :)

After your next empty and fill..

Drop your PH to 7.0/7.2

Measure FC and start the SLAM Process

Test FC and CC as much as you can, I test every 2 hours.. Try to stay as close to SLAM level as possible.. Whatever your CYA ends up being follow the chart and add that SLAM amount of liquid chlorine.. FC/CYA Chart PoolMath

You are already understanding TFP and you will do great during the SLAM.. If you have any questions at all come back to this thread and ask away.. You will not believe how clear pool water can be until you are done... :)
 

stillios

Member
Apr 22, 2021
19
Columbus, OH
THANK YOU for the advice! I was very unsure about the pH situation. I plan to start the process in the morning and am able to be home all day to test FC and CC often. I am so glad I found this site and community!
 

cowboycasey

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remember do not check PH during the SLAM or anything else except FC and CC.. above 10 FC PH reads high so only check PH below 10 FC :)
 

Msch99

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Jun 11, 2018
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Verona, MO
Should we turn off the chlorinator? How long should I wait before adjust the pH, if necessary?
If by chlorinator you mean using the tabs, I wouldn't use it, just straight chlorine.

FYI, according to most, muriatic acid is easier to use than dry acid, no mixing etc. Maybe see if you can return the dry. Lowes and others carry muriatic acid. Used for concrete etching etc.
Adjust PH to ~ 7.2 before slam with high FC, PH test not accurate above 10ppm.

Note on CYA test. Always round up to nearest line. IE: 65 would be 70. Scale isn't like a tape measure, half way between 60 and 70 isn't 65. Instead of looking at the lines while adding the mix, I add to 90, look for dot, add to 80 etc. Easier for me anyway.
 

stillios

Member
Apr 22, 2021
19
Columbus, OH
If by chlorinator you mean using the tabs, I wouldn't use it, just straight chlorine.

FYI, according to most, muriatic acid is easier to use than dry acid, no mixing etc. Maybe see if you can return the dry. Lowes and others carry muriatic acid. Used for concrete etching etc.
Adjust PH to ~ 7.2 before slam with high FC, PH test not accurate above 10ppm.

Note on CYA test. Always round up to nearest line. IE: 65 would be 70. Scale isn't like a tape measure, half way between 60 and 70 isn't 65. Instead of looking at the lines while adding the mix, I add to 90, look for dot, add to 80 etc. Easier for me anyway.
Thanks for the response! I'll round up on the CYA going forward. It was at 40 this morning, so I'm happy about that.
 
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stillios

Member
Apr 22, 2021
19
Columbus, OH
Wednesday Morning Results:

FC -- 5.5
pH -- 7.6
TA -- 60
CYA -- 40

I added dry acid to lower the pH (using the PoolMath app calculator) and then added enough liquid chlorine to raise FC to the SLAM recommended level of 16, again using the amount suggested by the PoolMath calculator.

10:30 AM: added liquid chlorine
Noon: FC was 17.5 (I guess what was in the bottle was stronger than what was on the label?) and CC was 0.
1:30 PM: FC was 17 and CC was 0

I guess I expected FC to go down more quickly and CC to go up. I'm pretty sure I'm using the test kit properly. Do I need to do something else or just be patient?
 

cowboycasey

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just be patient :)

Overnight it went from 16 down to 5.5, that is getting some algae right there :)
 

stillios

Member
Apr 22, 2021
19
Columbus, OH
just be patient :)

Overnight it went from 16 down to 5.5, that is getting some algae right there :)
FC was 6.5 yesterday morning and 5.5 this morning with 15 new inches of water and no added liquid chlorine (just what came from the chlorine tabs). I attempted to raise it from 5.5 to 16 this morning and overshot a little, measure 17.5 ninety minutes after adding in the liquid chlorine. So I'm not exactly sure where it started at 10:30 am, but between noon and 1:30, FC decreased by 0.5 and CC stayed at 0.
 
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stillios

Member
Apr 22, 2021
19
Columbus, OH
I'm kind of discouraged this evening. The pool doesn't look any better to me. I measured FC about every few hours today, and these were the results:

9:17 AM: 5.5
10:38 AM: Added 443 oz bleach to try to reach 16.0 FC
Noon: 17.5 FC
1:36 PM: 17.0 FC
3:18 PM: 15.5 FC
3:44 PM: Added 24 oz bleach
5:22 PM: 15.0 FC
5:29 PM: Added 44 oz bleach
7:41 PM: 15.5 FC
7:45 PM: Added 24 oz bleach

I know it is good to keep the levels up at 16, but I guess I expected it to drop more between measurements. It was sunny here today. I know the CYA measurement from this morning is kind of subjective, but I really don't think it was over 40. We have a sand filter. Is this just how long it takes? No visible difference over the course of a day? Well, actually, it is harder to see the bottom in the deep end now. I could see the white drains down at the bottom this morning but can't now. I did use the brush during the day to try to loosen some gunk from the floor and sides.

This morning:
IMG_3377.jpeg
This morning:
IMG_3376.jpeg

This evening:

IMG_3386.jpg

This evening:
IMG_3383.jpeg

Does this seem normal? Any advice?
 

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Newdude

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Jun 16, 2019
10,873
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Does this seem normal? Any advice?
Very normal. You need some pop. Pool owner patience. The early stages have progress thats visible by the hour it seems. The more you kill and filter out, the slower the rest goes.

But you're still chewing through FC so you definitely are killing, just not seeing the big difference in appearance.

Just to make sure, you are testing after adding chlorine to verify you hit your target, right ? Something so simple is often overlooked and not being at full SLAM slows things down a bunch. And makes it look like the losses are greater than they really are.

Anywho, we are in this with you. Stay the course. You got this. :)

*also. 2 hour testing............ BRAV- (and I can't state this enough)-O. Well done.
 

stillios

Member
Apr 22, 2021
19
Columbus, OH
Very normal. You need some pop. Pool owner patience. The early stages have progress thats visible by the hour it seems. The more you kill and filter out, the slower the rest goes.

But you're still chewing through FC so you definitely are killing, just not seeing the big difference in appearance.

Just to make sure, you are testing after adding chlorine to verify you hit your target, right ? Something so simple is often overlooked and not being at full SLAM slows things down a bunch. And makes it look like the losses are greater than they really are.

Anywho, we are in this with you. Stay the course. You got this. :)

*also. 2 hour testing............ BRAV- (and I can't state this enough)-O. Well done.
Thanks for the support! I am trying to be patient! :)

Actually, I have not been testing right after I add chlorine, because I guess I just assumed that if I added the amount the PoolMath app said it would get there. However, what you said makes perfect sense, and I will start doing that. How long do I need to wait after dumping the bleach in before testing to confirm SLAM levels?

Also, what if I am slightly wrong about the pool's volume? I used an online calculator to input dimensions and the depths of the shallow end and deep end. Do you think the pictures and log from today might suggest something is amiss with the calculation of my target FC (maybe the volume)? Should I consider using a target FC of, say, 17 instead of 16? It has taken all of my restraint not to dump extra gallons in all day, so I am aware of the problems with too much FC, but I thought I should ask. I'd hate to be sitting just under the target all day!
 

Newdude

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Jun 16, 2019
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How long do I need to wait after dumping the bleach in before testing to confirm SLAM levels?
20 mins with the pump running like it already is. There are a few reasons why poolmath could be off. Weak bleach (unbeknownst to you), gallons being off, etc. Always verify, even post slam.
Also, what if I am slightly wrong about the pool's volume?
Test after adding and if you consistently need XX more a 2nd time we can reverse engineer your gallons from that. As long as you get to target, it doesn't matter if it takes 2 tries.
Should I consider using a target FC of, say, 17 instead of 16?
Nope. Verify target after adding and we will sort the rest out as it goes.
Thanks for the support!
That's what we do. :) Also, if it helps any... anyone who sees through a proper SLAM is minted in fire with an education at the school of hard knocks. It's a crash course from no-to -pro in a matter of 2 weeks. Not only will you test and know what to do blindfolded afterwards, you'll have an appreciation for why you will never want to do this again. And the normal testing regimen is a fraction of what you're doing now. You will happily keep tabs on it.
 
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Msch99

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By testing ~20 minutes after could help nail down pool volume a bit too. If consistently over or under target, adjust volume a little.
 
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stillios

Member
Apr 22, 2021
19
Columbus, OH
I apologize for disappearing yesterday mid-SLAM. I had to be out of town all day, but I had trained my 14 year old daughter to test the FC and add bleach (she reported to me and I used the app to calculate). The pool visibly improved yesterday. This morning it was no longer green but was still dull and cloudy and had stuff floating on the top again. I could see the bottom of the deep end pretty well though. I tested FC and added more bleach. After that it got much more cloudy, and the bottom disappeared again.

When should I start testing things other than FC and adjusting them? I am asking this now because I had a confrontational interaction with the pool service guy today. Side note: the pool service owner is a friendly guy but the tech... isn't. The owner and I had talked about my taking over the pool at some point and just using them for opening and closing. I contacted the owner this week and told him I was doing stuff to the pool and asked him to tell the tech to talk to me today before doing anything to the pool. The owner indicated the tech would be willing to teach me a little about the equipment, so I wanted him here on schedule one last time to learn some stuff. Well, he was VERY ANGRY about the state of the pool and my use of the testing kit. All I need are the little strips he uses, he has plenty of crystal clear pools with CYA over 300, blah, blah, blah... Mocked my testing kit multiple times. Whatever, it's MY pool. He did show my husband how to use the manual vacuum before he left, so at least we got something out of it.

Anyway, the guy was flipping out about the pH and alkalinity, which I have not been testing during this SLAM process. He told me my pH was 6.2 (just tested, it's about 7.8) and my TA was 20 (it's about 60). My current values seem reasonable to me mid-SLAM, but now I need some reassurance or direction, since I'm new at this. Do I need to be doing something else to make the water not so cloudy now that the green hue is gone? The pool guy said we need to add "Revive" and vac to waste. I don't even know what comprises Revive and definitely am not inclined to follow his advice.

I have the robot vacuum in there right now after reading an old TFP thread about FC levels, CYA, and vacuums. I hope it's okay in there. Once again, I appreciate all of the advice and support. I really appreciate any and all feedback from people who don't mock my testing kit. :)

This is what the pool looks like now:
IMG_3400.jpeg

IMG_3401.jpeg
 

Newdude

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Jun 16, 2019
10,873
NY
When should I start testing things other than FC and adjusting them
We will get there after the SLaM is complete. As a quick example to the techs lack of knowledge, A FC at 10 or above skews the PH test and makes it invalid. He can test it all he likes but his answer isn’t right. So why treat something that you can’t tell ?
Do I need to be doing something else to make the water not so cloudy now that the green hue is gone
Nope. All to plan. Green is alive algae. Milky/cloudy is dead or dying algae. Usually here it shifts from a chemistry fight to a filtering fight. You’ve killed most the Algae, but you keep the FC up just in case. It’s much easier to do now than at the beginning of the process. While still maintaining the FC you now need to be patient and let the filter do its thing. This stage can drag on and seem miserable. Rest assured, you’re making progress, just not at a largely visible rate. Keep an eye on the psi and backwash at a 25% increase.
I have the robot vacuum in there right now after reading an old TFP thread about FC levels, CYA, and vacuums. I hope it's okay in there
It’s ok to swim in too if you can see the bottom for swimmer safety. The robots skin is way tougher than ours.
The pool guy said we need to add "Revive
No magic potions. Ever. Everything you need is in pool math. If it’s not listed, I don’t care that the name is PoolFixer9000Clear911. It’s crud.
I appreciate all of the advice and support.
We are here for you and taking the journey by your side. Ask away at anytime.
 

cowboycasey

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You are doing great.. No need to test PH or TA right now during the SLAM..

The PH test will read high with FC above 10, so your PH is still close to 7.2 to 7.4 right where you dropped it before the SLAM. That is why we have everyone do that.. He really has no clue if he did not know that..

*** changed **** :)
 
Last edited:

Wolfepack88

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You are doing great.. No need to test FC or TA right now during the SLAM..

The PH test will read high with FC above 10, so your FC is still close to 7.2 to 7.4 right where you dropped it before the SLAM. That is why we have everyone do that.. He really has no clue if he did not know that..
You mean PH or TA right, not FC or TA?? you have to keep testing FC correct? I'm new and expect to be here as well so I am reading this and that comment threw me off. Assuming a typo?
 

cowboycasey

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first cup of coffee :)

Should have read like this..

No need to test PH or TA right now during the SLAM.

The PH test will read high with FC above 10, so your PH is still close to 7.2 to 7.4 right where you dropped it before the SLAM.

Sorry about that, I hate it when I switch things like that..
 
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Wolfepack88

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first cup of coffee :)

Should have read like this..

No need to test PH or TA right now during the SLAM.

The PH test will read high with FC above 10, so your PH is still close to 7.2 to 7.4 right where you dropped it before the SLAM.

Sorry about that, I hate it when I switch things like that..
No worries I thought, Dang I have to go back to pool school as I don't get it yet.
 
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