Can I SLAM with 87 CYA?

[bsgross]

Hello! Readings today:
FC: .66
CC: 1.11
pH: 7.9
TA: 78
CH: 323
CYA: 87

CYA was 130 yesterday, I drained about 50% and refilled, targeting 55-60 CYA, ended up at 87. I reallllly don’t want to repeat that process but to SLAM pool math says bring FC to 34ppm. That seems VERY aggressive… can I tone that down or do I really need to bite the bullet and drain/refill again to cut CYA below 60?

Also I just added 3lbs of sodium

bicarbonate to boost that alkalinity a bit and will add some acid this evening to drop pH to 7.5-7.6. Then I’m going to SLAM.

Using 12.5% liquid chlorine as sanitizer.
Picture is from refilling last night.

 

[mknauss]

You need a proper test kit to perform the SLAM process. Post test results from your own test kit.

 

[bsgross]

You need a proper test kit to perform the SLAM process. Post test results from your own test kit.

Darn, my TF Test Kit will arrive on Tuesday 5/30. Guess I will have to wait until then to SLAM… but I know I have algae and was hoping to use pool some this weekend.

What should I do until Tuesday when I can start SLAM? Try to keep chlorine at a certain level to avoid more growth? Should I stay out of water until I can complete SLAM? Thanks!

 

[mknauss]

Add 5 ppm FC worth of liquid chlorine each day.

Is that the picture of your pool? Looks pretty clear to me. Algae is not an issue to swim in. Just be sure you have 5 ppm FC or more when you plan to swim. You must be able to see the bottom of the pool in the deep end.

You should never need to add baking soda to a pool in Phoenix. Your fill water TA is 130 ppm.

 

[duraleigh]

+1 what mknauss said.

 

[bsgross]

Add 5 ppm FC worth of liquid chlorine each day.

Is that the picture of your pool? Looks pretty clear to me. Algae is not an issue to swim in. Just be sure you have 5 ppm FC or more when you plan to swim. You must be able to see the bottom of the pool in the deep end.

You should never need to add baking soda to a pool in Phoenix. Your fill water TA is 130 ppm.

Yes that is my pool. It is pretty clear, but the walls and steps continue to turn green after a day or so I think algae is still present somewhere. I can keep it at 5ppm until Tuesday and then do a OCLT to determine if I need to SLAM.

Also, I have thought the same thing about TA in my fill water.. but my test from pool store read 78 today. Is that any indication of an issue that TA is lower than expected?

 

[mknauss]

Pool store test. Do not use them to make chemical adjustments.
Their TA is 'adjusted'. So now you will be adding lots of acid to consume the alkalinity you added.

 

[bsgross]

Pool store test. Do not use them to make chemical adjustments.
Their TA is 'adjusted'. So now you will be adding lots of acid to consume the alkalinity you added.

Hahaha of course… I knew better than to listen and buy what they suggested. I’ve read a lot this week on being Pool Stored. I went strictly to get a CYA reading after yesterdays drain/refill. I’m impatient and didn’t want to wait on this test kit. But from what I had read here I thought I should bump TA up in range, I did not consider their readings being adjusted.

I am actually hesitant to add more acid because I just read about ammonia. I highly doubt I have it but want to be sure, if I do have any I understand that process will add a lot of acid as byproduct.

I’m going to wait on my kit and try my best to maintain 5ppm FC until then.

 

[mknauss]

You do not have ammonia. You would have 0 CYA, 0 FC, high CC, and very low pH.

 

[bsgross]

You do not have ammonia. You would have 0 CYA, 0 FC, high CC, and very low pH.

Ok then I will add some muriatic acid to get pH in range before I chlorinate.

Back to my original question, with CYA of 87 do you recommend I drain/refill more or should I SLAM at 34ppm? Or can I also not trust the pool stores CYA reading?

It’s becoming clear I should have opted to pay for express shipping on that TF-100 test kit!

 

[mknauss]

When you get your test kit, run a full set of tests and post the results here.

 

[Newdude]

The good news is that the pool store is arguably worse at the CYA test than they are at the others. It may not be as high as you think.

I reallllly don’t want to repeat that process but to SLAM pool math says bring FC to 34ppm. That seems VERY aggressive…

With chlorine being bound to the CYA, every level on each of these 2 charts are equal. If you have more CYA, you need more chlorine to accomplish the same sanitizing.






But let's wait and see what the real test kit says.

 

[bsgross]

When you get your test kit, run a full set of tests and post the results here.

Hello! Test kit arrived! I kept at 5ppm over the weekend and did my OCLT last night at 10ppm. That test failed, FC was around 3ppm this morning. So as I understand, time to SLAM. I retested this afternoon, results below:

FC: .5
CC: 0
pH: 7.8
TA: 110 (you’re gonna get me on this one lol, my posts above can explain this)
CH: 375
CYA: 50

So as I understand I need to SLAM, FC at 40% of CYA or for me 20. About 6 hours ago I went ahead and started that by adding 213oz of 12.5% liquid chlorine. I need to read up more on SLAM process because I am not certain the process to properly maintain. I tested again about 3 hours later and FC was already down to 12.5. Probably a combo of sun and algae but wasn’t sure if that’s normal or how often I need to bump it back up to 20. I will do my reading on that now but just wanted to update you and see if you have any guidance. Thank you!

 

[JJ_Tex]

I need to read up more on SLAM process because I am not certain the process to properly maintain. I tested again about 3 hours later and FC was already down to 12.5. Probably a combo of sun and algae but wasn’t sure if that’s normal or how often I need to bump it back up to 20. I will do my reading on that now but just wanted to update you and see if you have any guidance. Thank you!

Please read the SLAM documents a couple of times, but in quick summary:
- Step 1 is dropping your pH to 7.2. I didn't see where you did that. Add enough acid to drop it to 7.2 from your 7.8 reading.
- 20 is your FC target, test and add chlorine multiple times a day to maintain the FC at 20. Generally the more times the better, since as you can see the FC will be consumed by the algae fairly quickly at first.

 

[PoolStored]

Probably a combo of sun and algae but wasn’t sure if that’s normal or how often I need to bump it back up to 20.

Normal.

I will do my reading on that now but just wanted to update you and see if you have any guidance. Thank you!

Print the instructions out. Read them three times. Keep them in your back pocket. If a question comes up, read it again first. I found having paper copy available for reference really helped and answered most if not all my questions! If you can't find answer there, post up!

 

[bsgross]

@JJ_Tex @PoolStored thank you both! Will read it over and over and over and print it out to read again!

Also JJ you’re right. I didn’t do that. Will add my acid now and re-chlorinate in about an hour. Thankfully I did buy the SLAM kit with my test kit so I’m prepared to do 50+ tests this week! I sourced my own stirrer from Amazon but wow that is a must. Appreciate you guys!

 

[PoolStored]

wow that is a must

No Question!

 

[Newdude]

CYA: 50

Yet once again, a considerable difference between testing methods. And proof yet again that if we advise on the method thats routinely off, it's bad advice. They were off by almost a factor of 2.

You're sitting pretty going forward. We got you now.

 

[bsgross]

We got you now.

Yes I’m in good hands now. Just ran another set of tests to ensure pH is down to 7.2 to start SLAM. Had to add 30 oz of acid last night, just did another 13 oz to drop it a bit more. That is also helping drop my TA too.

FC 4.5
CC .5
pH 7.4
TA 100
CH 375
CYA 50
I will retest pH in an hour or two and if I’m down to 7.2 I will start my SLAM at 20 ppm. Gotta say the pool already looks wonderful. Woo!

 

[PoolStored]

You can test pH 30 minutes after you add it...