CYA help please

[sealy99]

So started a slam three weeks ago. 40k gal pool. Fighting green and cloudy where I couldn't see the second step for a year and a half. Finally fired the pool company a month ago. Start of the slam, had zero cya. Brought cya up to 40 and waited three days, held at 40. Brought ph down to 7.2 and started the slam. I've gone through in the neighborhood of 300 gal of bleach in three weeks. I've been brushing about every other day, but this morning got aggressive with it and used a wire brush. (Gunnite pool). This morning (8 hours ago) when I checked my FC level before brushing, my FC lvl was 25. Just checked it and it's down to 4. Added three more gal of 8.25% bleach and then out of curiosity, checked CYA levels again due to the high chlorine consumption during the day. CYA is back at zero after testing it twice. This would explain the excessive chlorine loss over the last 3 weeks as well as the slow results on the slam I think due to the wild swings in FC levels. But what would cause the CYA consumption? I do not have a leak in the pool and have added minimal water over three weeks due to evaporation.

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[Wildcat]

I am not the resident expert here but let's start with the obvious.... you are right, these numbers don't make sense. From 25 to 4 FC level in 8 hours? CYA of 40 to zero?
From what we know, nothing causes CYA to disappear. What test kit are you using to measure FC and CYA?

300 Gal of bleach in three weeks?


Please put pool specs in your signature

 

[aussieta]

as i found out recently ammonia will burn through your cya and fc very quickly
but to fix it you slam at a reduced level for no cya until fc holds for a few hours
which yours appears to do
have a quick read of this post, and see if there is anything useful
LAST DITCH EFFORT....and I don't know what to do now
i am sure one of the experts will be along soon to help you out

 

[pooldv]

Yes, it is possible that there are bacteria in the pool eating CYA and consuming much higher than normal amounts of chlorine. Test and add chlorine to 10-15ppm every hour or so to kill the bacteria and it holds chlorine better. Once it holds chlorine level for a couple of hours add 30ppm CYA and resume your SLAM. Keep chlorine at shock level (12ppm) at least 2-3 times per day to avoid the bacteria returning.

 

[sealy99]

I've read that thread. Found it encouraging. Can't seem to update my signature with the mobile version of this site, but:
40k gal in ground Gunnite
Hayward Sand Filter
Well water

Maybe it's ammonia causing it?
I miscalculated the bleach consumption. I'm going through an average of 50 gal a week. So 150 total over three weeks. When I had the cya at 40, shock lvl should be 18 I believe. I'd bring it to 20 to 22 in the evening g after work and it would be at about 15 by the time I got back out there in the am. By the time I'm back at 7 or 8 that night, it's back down to between 4 and 6. I'm using the Taylor TF-100 test kit doing the drop test. Pool has improved over three weeks to the point where I can just make out the bottom drains looking at the deep end , but it's still a bit cloudy with a distinct green tint to it

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[Donldson]

Your situation does not indicate ammonia. Would you mind posting a complete set of results?

Typically in this situation there are only 2 possibilities: a leak or testing error. Since you have ruled out a leak then I am inclined to believe you may have made an error during one of your tests. If you are certain your current CYA is zero then you need to get that back up.

From my HTC One via Tapatalk

 

[sealy99]

FC-12
CC-.5
TC-12.5
CH-100
TA-320
CYA-0
PH-8.2 (or higher. Can I trust results with an FC reading of 12?)

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[Wildcat]

FC-12
CC-.5
TC-12.5
CH-100
TA-320
CYA-0
PH-8.2 (or higher. Can I trust results with an FC reading of 12?)

Sent from my SAMSUNG-SM-G870A using Tapatalk

Are your CH and TA numbers reversed?

PH will read false high usually with FC over 10

 

[Donldson]

The high FC will skew your pH, but with your TA that high it will creep up quickly. If you have been SLAMing for a while then you might want to let your FC drop below 10 and get your pH readjusted before continuing.

Ammonia does not cause CYA loss. There is a very specific situation where bacteria can consume CYA and convert it to ammonia but it can only happen if your FC is zero. There is a possibility that you had the bacteria in your pool before you started the SLAM and it consumed your CYA before you got rid of the ammonia it produced (which could explain your massive chlorine usage) but your ability to hold FC now indicates that the bacteria and ammonia are both long gone. So adding CYA and continuing the SLAM from here is the way forward.

 

[sealy99]

This pool was pretty bad before I started, so there's a good chance that cya was eaten up in the beginning. I'll check ph after fc drops. Should only be a couple of hours at this point. This has been a long journey so far.


Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[sealy99]

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[epro05]

Re: LAST DITCH EFFORT....and I don't know what to do now



OK, no more CalHypo You were at 380 before you did that, so you are probably way too high. You want bleach, lots of bleach. 10 or 12.5% chlorinating liquid would be better, but I don't know about sources in PA.

Go to WalMart tomorrow. Buy lots of bleach. They will think you are crazy, but you need it. Buy stabilizer, but don't put it in the water just yet, I want to test something.

When you get home with the pump running add 2 gallons of the WalMart bleach. 30 minutes later test the water for chlorine. As you opened the pool with no CYA (it was there last year, correct?) it had ot go somewhere. There is a bacteria that can consume CYA and at times convert it to ammonia. If after 30 minutes the FC is back down to "0" you have ammonia in the water. The way to get rid of ammonia is the same as getting rid of algae, chlorine. But, ammonia consumes a lot of chlorine as it is oxidized, so you will be going through a lot, quickly. Ammonia will consume the chlorine almost as quickly as you pour it in the water. But, once the chlorine begins to hold and you get a reading the ammonia is generally gone.

Once we have verified no ammonia, or you have removed it with bleach you need to add CYA via the sock method to get your level up to 30. It won;t registeron the test for a week, so don't bother testing. Just put the correct amount in a sock and hang it in front of a return.

Now the SLAM begins. The pump should run 24/7

With a CYA of 30 your target for FC is 12. maybe stretch that to 15 at times, but 12 is your goal. Starting with "0" FC that is 3 121oz bottles of 8.25% bleach. Wait at least an hour and test for FC again and add whatever chlorine Pool Math tells you you need to get back to 12. You will repeat this multiple times a day until your pool is clear. At least once a day you need to brush the entire pool.

A SLAM takes a lot of effort, but when you are done you will have a beautiful pool.

Post#5 above in the link, by tim5055, could explain this. A type of bacteria eats CYA. The CYA you added could have given it more to eat. This could explain the FC loss and the CYA loss.

 

[sealy99]

I'm assuming the green is from algae being present still?

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[Texas Splash]

You are correct. The pics looks like you are still battling a healthy dose of algae. Until your CYA begins to build to protest your FC, chlorine will disappear faster than normal along with the fact it is battling algae in our hot Texas sun. Stay aggressive and consistent. As Tim noted above, keep your FC at a SLAM level of 12, possibly even 15 at times. Continue with the pump on 24/7, and scrub the pool as much as you can to keep the algae from getting a grip on your pool surfaces. Hang in there!

 

[sealy99]

FC at 9 now. PH still reading between 8.2 and 8.5. Going to bring it back down to 7.2. Do I understand this correctly? High PH will reduce the effectiveness of chlorine?

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[sealy99]

Thanks for the replies btw. This site has been helpful. Even with the issues I'm having, pool still looks better than when it was "professionally" cared for

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[Donldson]

Your statement about pH is correct for water with no CYA in it. Once you add CYA then pH has minimal affect on chlorine efficiency. You mostly want to drop your pH because it will often trend upwards during a SLAM but you won't be able to accurately measure and adjust it.

I have to say, if the picture you just posted is better than it looked while it was professionally managed then I highly question the term "professional"... You are going to be pretty awestruck when things really start to clear up.

 

[Divin Dave]

Hi Sealy,

Its important to know whether or not the ammonia or whatever it was, is gone before adding anymore CYA.
Weve been discussing behind close doors how best to do this, and I'm presenting it to you. Since you seem to be holding some FC now, you may be over the hump, but better safe than sorry.

Step 1. Test your CYA with your test kit.
Step 2. Bring the FC to SLAM Level. (Slam is 40% of your CYA level)
Step 3. Test FC 10 minutes after you bring it to SLAM
Step 4. Test FC again the next 10 minutes

Post the results here please.

Fingers crossed that you have defeated whatever it is the consumed 300 gallons of bleach. Geesh!

 

[sealy99]

I can do that. With CYA at 0, what would be the correct FC to have at SLAM level. This will likely be tomorrow as I am again out of bleach

Sent from my SAMSUNG-SM-G870A using Tapatalk

 

[Divin Dave]

Hi Sealy,

with 0 CYA, slam FC is 4ppm.

Tomorrow will be fine

Here is the procedure for how to proceed. We believe that if you loose 50% of your SLAM level FC in 10 minutes, then the culprit is ammonia.
The procedure is basically the same as a SLAM, but for ammonia, test and add chlorine every 10 minutes. Waiting longer just gives the ammonia time to increase.

Procedure written by BoDarville

Symptoms:
1. A sudden drop in CYA that is unexplained by any other phenomenon. NOTE: CYA level does not necessarily have to drop all the way to zero.

Diagnosing:
1. Test CYA level and record result
2. With pump running, dose FC to Shock (SLAM) per level per Pool School - Chlorine / CYA Chart, then retest FC after 10 minutes. If FC level drops by more than 50%, then proceed with treatment for ammonia.

Treatment for Ammonia:
1. Begin a SLAM and dose FC up to SLAM level. Do not add additional CYA at this point.
2. Retest FC at 10-minute intervals.
a. If FC loss is greater than 50%, add FC to bring back up to SLAM level and continue retesting FC @ 10-minute intervals.
b. IF FC loss is 50% or less, add FC to bring back up to SLAM level. Go to Step 3.
3. If CYA is below 30 ppm, add enough CYA to bring level up to 30 ppm.
4. Continue SLAM as directed in the SLAM article until the SLAM Criteria of Done are met. Test as directed in the SLAM article - no longer need to test FC at 10 minute increments at this point.