Opening pool-Low FC, High CC...ammonia?

[STL]

Hello, lots of great info on this site. Our 30k gallon Pebble sheen pool was new last season. The pool company closed it and came by a few times over the winter to do who knows what.

I filled the pool the 2.5 feet or so to make it full yesterday and started the pump. I’ve brushed it a few times and used my TF-100 kit. CYA was zero, I could see the black dot like I was lookig thru tap water. After the pump ran for 30 minutes I added 54oz of muriatic acid as my PH was over 8.2 at 7:00 PM. Then an hour later added almost 3 gallons of 10% chlorine. Put some CYA in the skimmers in socks but removed that after about 45 minutes of doing some reading here on my CL #s and wondering if I had ammonia. Since I started yesterday evening I’ve added 14 gallons of 10% chlorine. My numbers 30 minutes after adding 3 gallons at 7 this morning were:

FC 1
CC 9

I added another 3 gallons at 7:40 am had to do some work stuff then re tested twice from different spots in the pool at 10:45 am and had:

FC 1
CC 7.5

i added another 3 gallons at 11 am and figured I’d post here to make sure I’m not missing not something.

 

[Texas Splash]

Hello and welcome to the forum! Ammonia? ... maybe, maybe not. Not enough info at this point really. The elevated CCs are definitely an indication of the chlorine removing something. But going back to the winter closing, what was added to the water back then do you know? Antifreeze, algaecides, etc? Any of those could also be a reason why your CC are elevated.

Either way, the treatment is about the same ..... maintain that FC level. Since your CYA is assumed to be zero, increase the FC to "10" and test every 10 minutes. Whatever dropped, add it back to maintain 10. Continue that cycle every 10 minutes until the FC stays at 5 or above after 10 minutes. Once you get that far, then you can add stabilizer for a CYA goal of "30" and increase the FC to "12" for a regular SLAM.

For now though, don't add anything but bleach and follow that 10 minutes drill above until it holds. Good luck!

 

[STL]

Thanks. Added 340 oz and after 10 minutes was at 4 FC. Added another 226 oz and will test here in a few minutes. I’m waiting on my wife to show up with more chlorine.

If im at or above 5 FC at this next test I will add to get me to 12 and add some CYA to the skimmers. How often can I go between tests and additions at that point?

 

[Texas Splash]

How often can I go between tests and additions at that point?

Start again at 10, but then you should back-off slowly spreading out to perhaps 20-30 min, then eventually an hour or so. You're in the fight right now, in time that volatility will slow down. Massive chemical reactions going on right now.

 

[STL]

Thanks. Hopefully my wife gets her with chlorine. I’m all out. I don’t know what they did chemical wise at close or throughout the winter. Just tested after 10 minutes and was at

FC 6.5 and CC 1.5

I added the last of my chlorine which was within 6 oz of what the pool math called for to bring to 12 and put some CYA in the skimmers in socks.

Should I be regularly brushing the pool after each dosing? It’s looking clearer and I can see the bottom at about 5 feet now.

 

[Texas Splash]

FC 6.5 and CC 1.5

There you go! Much better.

Should I be regularly brushing the pool after each dosing? It’s looking clearer and I can see the bottom at about 5 feet now.

You will need to brush, but not after each chlorine dosage. Just once a day would be good. Inspect everywhere in the pool where water might get stagnant and not circulate like behind a light, or inside hollow steps/ladders. Watch your filter pressure too. Know your beginning (clean) pressure, and when the filter gauge increase by 20-25%, it's time for a rinsing or backwash. Review that SLAM page guidance, maintain the FC of 12, and you'll do fine.

Don't stop the SLAM until you pass all 3 SLAM criteria!

 

[STL]

I will continue with the SLAM process but wanted to know if or when I should add acid to bring my PH down since the SLAM page says the PH test isn’t reliable when SLAMing.

 

[Texas Splash]

Ahhhh rats. I thought we already talked about that, obviously we did not. Yes, at some time when you feel it good for you, let the FC fall just under 10 long enough to grab a water sample for the pH. Since I'm assuming you'll be using muriatic acid for the pH, just make sure to never pour the acid and bleach in the same area at the same time. Your pump should be running, so add the acid, confirm your new pH level between 7.2-7.4, then go ahead and resume the SLAM of 12.

 

[STL]

Thanks. It’s falling back to 7.5 FC very 30 minutes. I add chlorine to get me back to a 12 (don’t test to verify) then check after 30-35 minutes and it’s back to 7.5. I’m hoping it starts to gain some ground here. Thanks for your help!

 

[STL]

Well it’s starting to work! My FC only dropped from 12 to 10 in 3 hours (7-10PM) this evening and my CC was 0.5. I added more chlorine to get up to 12 and will check it tomorrow morning. The pool is looking much better in the first 24 hours.

My pH was down to 6.9 from 8.2+ On its own so I’m not sure what caused that. Should I bring it back up? I was thinking of adding acid to bring it down earlier today only to retest it when my FC dropped to 8.5 and find out it’s now on the low side.

 

[Texas Splash]

Well it’s starting to work! My FC only dropped from 12 to 10 in 3 hours (7-10PM) this evening and my CC was 0.5.

Outstanding!

My pH was down to 6.9 from 8.2+ On its own so I’m not sure what caused that.

That is odd as the pH will increase when the FC is over 10. In this case, the higher FC level is working in your favor. I'd leave it for now and re-test after the SLAM.

Keep up the great work! I hope you are taking a picture of the water changes each day.

 

[STL]

An update:

The pool water looks great. It’s crystal clear. I’ve been increasing FC to 12 anytime it gets down to 9.5 or 10. There is some brown dust when I brush the pool that I can see directly around the brush as it moves. I’m not sure if this is some sort of algae or pollen. We have a lot of trees around but none directly over the pool.

I ramped the FC up to 14 overnight and it was 10.5 this morning before the Sun was directly on the pool. This morning I took out the 3 light fixtures and scrubbed the niches and housings and wiped down the wires. They were all slimy with a light white residue on them. I then added enough chlorine to get it back up to 14 and left the lights on the bottom of the pool for now to get some fresh water in and around them. I just checked the water and it was 9.5 FC and 0 CC after 4 hours. Added more chlorine to get up to 12 again but am not sure if I’ll pass an OCLT yet. My CYA yesterday was just less than 20 as the black dot was still visible but barely when doing the test. I still had some undisolved CYA in the skimmer sock and possibly some in the filter. I used the amount the pool math calculated to get the pool from 0 to 30 but maybe it’s taking longer to adjust/dissolve.

 

[Texas Splash]

You're doing exactly what needs to be done - good job. Stick with it consistently and patiently. As you approach the tail-end of the SLAM, this is where it can be most difficult for some as they simply want to quit. Don't do it! Make sure to continue until you pass all 3 criteria. Getting closer! It will all be worth it.

 

[splashpad]

This was a fun read!

... My CYA yesterday was just less than 20 as the black dot was still visible but barely when doing the test. I still had some undisolved CYA in the skimmer sock and possibly some in the filter. I used the amount the pool math calculated to get the pool from 0 to 30 but maybe it’s taking longer to adjust/dissolve.

If there is still some undissolved, your CYA won't read at full amount Try not to backwash for a few days, so you don't lose your undissolved CYA

 

[STL]

Well I’m at day 8 of the SLAM and still lost 3 FC overnight. The water has been crystal clear since the end of day 2 but I cannot pass the OCLT. I’ve scrubbed the lights, skimmers, niches, brushed the pool and cleaned the cartridge filters and housing on Saturday. I’m consistently losing 3-3.5 FC each night. My CYA has been below 20 every time I’ve tested it so I’ve been using 12-14 as my SLAM chlorine level. Should I increase the amount of FC? It’s getting old looking at this crystal clear pool with 0.5 or less CC but not being able to pass the OCLT.

 

[splashpad]

Well I’m at day 8 of the SLAM and still lost 3 FC overnight. The water has been crystal clear since the end of day 2 but I cannot pass the OCLT. I’ve scrubbed the lights, skimmers, niches, brushed the pool and cleaned the cartridge filters and housing on Saturday. I’m consistently losing 3-3.5 FC each night. My CYA has been below 20 every time I’ve tested it so I’ve been using 12-14 as my SLAM chlorine level. Should I increase the amount of FC? It’s getting old looking at this crystal clear pool with 0.5 or less CC but not being able to pass the OCLT.

If you're water is clear, you can bump the CYA up (per PoolMath) +10 for a goal of 30 to help stabilize your chlorine (you will also increase your required shock value per [FC/CYA][/FC/CYA]). We've got some good UV happening in the mid-west (in-between storms, lol)

The last part of SLAM is the hardest, because it takes perseverance! You. will. get. there!

 

[STL]

How long do I need to wait for the CYA levels to increase after adding? I put another 3 lbs in 2 days ago but don’t want to add so much that my levels get too high if it takes a week for it to show up on the test.

 

[splashpad]

How long do I need to wait for the CYA levels to increase after adding? I put another 3 lbs in 2 days ago but don’t want to add so much that my levels get too high if it takes a week for it to show up on the test.

And it's still not registering? What is your water temp?

Was the 3lbs to get you to 20 OR after you were already at 20? (just verifying)

 

[Texas Splash]

I’m consistently losing 3-3.5 FC each night.

That's a lot of nighttime loss. Something somewhere is eating chlorine. Your signature doesn't show it, but what type of filter do you have? Also, do you have a main drain? The stabilizer shouldn't take more than a couple days to register. As Splashpad notes, the water temp might be a factor in the testing.

Now might be a good time to post a pic of your pool and/or your equipment pad area so we can see what you have to work with.

 

[STL]

My water temperature is 75 degrees at the moment. I haven’t turned the heater on during the SLAM but water is flowing through it. The pump has been on 24 hours a day since I opened the pool.

I have a Sta-rite System 3 cartridge filter. I have a main drain and 2 skimmers. I haven’t had a CYA test reach the 20 mark on the tube. I’ll test again today when my wife gets home as I have 1 year old and 4 year old helpers that are hard to wrangle while I mess with the pool. Let me see if I can figure out how to post a pic of the pool and equipment.

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Photo attached

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