HELP

[Mr. Muriaticacid]

Unfortunately, I had to close my pool early last year and open late. Just the opposite of what is recommended. Needless to say, when I opened this past Thursday 4/25/24 it was a swamp. I had zero chlorine, and zero CYA and pH was very high. A half gallon of MA and my pH was 7.6. I next brought the chlorine up to what I thought should be 10ppm (2 gallons of 10% bleach). My initial set of numbers was this:
CL 4.5
CC 1
pH 7.6
TA 80
CH 400
CYA 0
BOR 0
Salt 2200
CSI negative .100

I proceeded to vacuum the swamp and was done for the day. Next day the CL was zero so thinking I needed some CYA I added 8 pounds of conditioner per Pool Math. I know I know, Pool Math is only a guide and I should have used half of the recommended dose and then checked it, but I didn't. The Pool Math calculation said I would be at 48 but I ended up at 70 which is pretty high for a slam. I added 3 more gallons of 10% bleach and then 2 more gallons to bring it up to slam because I kept losing chlorine. This brings us to today. I bought 12 gallons of 10% bleach from Wally. Starting at 10am today I added 5 gallons of bleach and every 30 minutes when checking the level if, it dropped, which it did, I would add 2 or 3 gallons more to try and find where the chlorine would hold but, it never held. I went all the way up to 54 ppm CL and 1 hour later it was 50. An hour and a half after that it was 44. Total of 11 gallons of bleach and still losing chlorine. To complicate things even more, we are under a severe weather threat and could get up to 5" of rain. I decided to wait until the weather passed before going any further, most likely on Monday, the 29th. I should point out that the CC is consistently at zero now. I bought an ammonia test strip kit and the ammonia is at zero per test strips for what they're worth.

So, now what. I am asking for help with this problem. This is the first time this has happened to my pool. The TFP method has kept things running smoothly since I joined but this is beyond my skill level. My guess is that I should drain to get the CYA down to around 30 and go at it again but even with a CYA of 70, shouldn't a 54 CL been enough to kill nearly anything? I really am baffled, and I surely could use some advice. Thank you in advance.

 

[ajw22]

Be patient.

54 CL is not a nuke that incinerates all algae immediately.

SLAM FC for CYA 70 is 28. There is little benefit to going above that.

Follow the SLAM Process step by step rather then freelancing.

Maintain FC of 28 until you meet the 3 exit criteria.

 

[Mr. Muriaticacid]

Thanks ajw, do you think it’s possible to do this with all the rain we have coming?

 

[ajw22]

Rain does not affect the SLAM process.

 

[Mr. Muriaticacid]

You mean that even though the rain is diluting the pool water I just need to keep it at 28 or higher? How will I know if I pass the OCLT if the rain is diluting the water? Should I wait for a rainless night for the OCLT?
I just checked and the CL is at 44, the same as it was over 2 hours ago. That’s a good sign, right?
I appreciate your comment to “be patient”, that’s not my strongest suit especially with everything else going on.

 

[ajw22]

I would be patient and wait until the rain passes for the OCLT.

As much as you can maintain the SLAM FC level during the rain.

 

[DaveTheAccountant]

Your pool is marginally smaller than mine. My math indicates my pool loses or gains 400 gallons per inch of water. If you’re adding an inch of rain you add 400 gallons to the pool, or 1.6% dilution. This will cause your FC to fall from 44 to 43.29 (although realize you can’t measure that). That’s certainly within MOE.

Hope this helps.

 

[ajw22]

Your pool is marginally smaller than mine. My math indicates my pool loses or gains 400 gallons per inch of water. If you’re adding an inch of rain you add 400 gallons to the pool, or 1.6% dilution. This will cause your FC to fall from 44 to 43.29 (although realize you can’t measure that). That’s certainly within MOE.

Hope this helps.

Glad we have an accountant on the frequency to crunch the numbers.

 

[Sunny Blues]

I wouldn’t mess with your CYA. We keep ours right at 60 all season long. Sometimes it’s at 70. We don’t like to run closer to 30 because backwashes and occasional fills or rain will lower it anyway and we don’t want to be on the lower border like that. Plus when you are at 4-5 ppm it’s quicker to lose chlorine and courting danger, especially if you get busy and a day or two goes by without testing. Keeping it at 50 or 60 gives you a little more wiggle room with a higher chlorine level and it doesn’t drop to danger zones as quickly.

After your rains and some backwashing you no doubt will have to do it might drop down to 60? Maybe? But even if it doesn’t you can do fine at 70 for a while. Just follow the CYA chart for your recommended chlorine levels and slam levels. After a few backwashings and maybe some more rain or adding water later in the year it will no doubt drop to 60 at some point.

 

[Mr. Muriaticacid]

I wouldn’t mess with your CYA. We keep ours right at 60 all season long. Sometimes it’s at 70. We don’t like to run closer to 30 because backwashes and occasional fills or rain will lower it anyway and we don’t want to be on the lower border like that. Plus when you are at 4-5 ppm it’s quicker to lose chlorine and courting danger, especially if you get busy and a day or two goes by without testing. Keeping it at 50 or 60 gives you a little more wiggle room with a higher chlorine level and it doesn’t drop to danger zones as quickly.

After your rains and some backwashing you no doubt will have to do it might drop down to 60? Maybe? But even if it doesn’t you can do fine at 70 for a while. Just follow the CYA chart for your recommended chlorine levels and slam levels. After a few backwashings and maybe some more rain or adding water later in the year it will no doubt drop to 60 at some point.
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I’m not worried about the CYA except as it relates to a SLAM. When doing a SLAM you would like the CYA to be around 30 so you can use less chlorine. Since my pool has a SWG I typically shoot for around 80 CYA normally.

 

[Lake Placid]

You seem to be significantly overreacting to chlorine loss/use. You lose chlorine the minute you apply it to your pool. Whether it be to UV degradation, organics that need to be sanitized, CC that needs to be oxidized, they all contribute to “loss” of chlorine. You opened to a swamp, of course you’re going to see a loss of chlorine to destroy the unwanted visitors in your pool. Run the SLAM as prescribed until the OCLT indicates you aren’t using chlorine in the sanitization/oxidation process. The chlorine loss just indicates it’s doing its job, try to relax and maintain the process. It won’t happen overnight and will likely take longer than the storms headed your way.

 

[Mr. Muriaticacid]

Thanks Lake Placid, you’re right about my over reacting. I didn’t think this through logically. For the last 10 years upon opening I would bring the chlorine to 10ppm and things would be good. I’ve never opened to this much algae and I went about it the wrong way. I appreciate all of the constructive feedback.

 

[Mr. Muriaticacid]

After approximately 6” of rain over the last 2 days I was able to maintain SLAM level reasonably well. I am definitely using less chlorine but my OCLT showed a loss of 3ppm CL this morning. As bad as I want to believe that my algae is gone I know that unless my OCLT is 1 or less that I’m not done yet. I plan on maintaining SLAM level for at least 1 more day.

SLAM Question 1: if the sun is rising but not shining on my pool yet, is that okay or should I check the chlorine even earlier?
SLAM Question's 2: how critical is it to remove and clean the bottom drain cover during SLAM? I don’t have a a way to remove the cover. Thanks!

 

[ajw22]

After approximately 6” of rain over the last 2 days I was able to maintain SLAM level reasonably well. I am definitely using less chlorine but my OCLT showed a loss of 3ppm CL this morning. As bad as I want to believe that my algae is gone I know that unless my OCLT is 1 or less that I’m not done yet. I plan on maintaining SLAM level for at least 1 more day.

Patience, patience...

Don't bother with the OCLT until your daily FC loss stabilizes at about 3PPM.

Why are you in a rush to complete the SLAM?

The OCLT can fool you and look good for a day and then have the algae come roaring back. It is better to keep the water at SLAM FC level for a few extra days while at SLAM level then stop the SLAM and then find out you need to start again from the beginning.

Run the SLAM for a few extra days and make sure your water is truly algae free.

SLAM Question 1: if the sun is rising but not shining on my pool yet, is that okay or should I check the chlorine even earlier?

Check the chlorine when you can. The chlorine does not immediately vaporize as soon as the sun peaks over the horizon.

SLAM Question's 2: how critical is it to remove and clean the bottom drain cover during SLAM? I don’t have a a way to remove the cover. Thanks!

It should not be unless you had a real muck situation at the bottom of your pool and think mud is stuck under the cover.

 

[Mr. Muriaticacid]

Why are you in a rush to complete the SLAM?

Just one more thing to deal with but I get your point. Since I’m already at SLAM it’s easier to maintain it than to start over. We’re not swimming yet anyways.

It should not be unless you had a real muck situation at the bottom of your pool and think mud is stuck under the cover.

It was pretty mucky, worst I’ve seen. I’ll close the main drain and try to get the vacuum hose down there and work it really good.

Thanks again for talking me down, lol

 

[ajw22]

Since I’m already at SLAM it’s easier to maintain it than to start over. We’re not swimming yet anyways.

Even if you were swimming, it is safe to swim up to SLAM FC level.

So before swim time let the FC drop by a PPM or two, go swimming, then raise FC back up to SLAM FC when done swimming for the day.

 

[Mr. Muriaticacid]

Due to the high chlorine I diluted the test sample 1:1 with distilled water which would give me a CL of around 15ppm. This might still be too high to be accurate. But let’s just say that it’s close. How long can my CSI stay like that before my plaster starts to suffer?

 

[ajw22]

How long can my CSI stay like that before my plaster starts to suffer?

About 6 months.

 

[Mr. Muriaticacid]

About 6 months.

lol, thanks man, you’re the best!!

 

[Mr. Muriaticacid]

Great news! I passed the OCLT! Zero chlorine loss overnight. I’m going to maintain SLAM for one more day, just in case. Thanks to all who have helped me, not only with my current problem but every problem over the years. This site is simply amazing and it has saved me countless time and money. Thanks again TFP and also to ajw22 who reinforced in me the importance of patience when it comes to our pools.