Pool Opening SLAM - FC Immediately Used Up (Ammonia?)

AR762

Member
May 20, 2024
5
New England
Hi TFP, I've been a long time lurker and this year decided to go all in on the TFP methodologies after two years of pool store ambiguity and hardships. I read pool school multiple times, and got started opening my pool on Wednesday.

I ordered my TF-Pro test kit, practiced with the samples, then got started. After opening day, PH was below 7 and CYA was below 30 (assumed to be 0) as I could fill the entire view beaker with the black dot clear as day. I then started to follow SLAM procedure, raising PH to 7.2, and adding socks with CYA to raise it to 30 CYA. I retested CYA after dissolving and circulating for a day, it measured just shy of 30 PPM. Great, time to start the SLAM, so I thought. The pool opening condition was rougher than last year, definite algae bloom and dark green color to it from our mild winter.

I vacuumed the majority of visible debris to waist. Then, I added my initial shock - 4 gallons of Liquid Chlorine to raise my 30k gal pool to roughly 12.8 PPM FC. Immediately after, I brushed a whole lot to suspend the algae and circulate the chlorine, pump running 24/7 at this point. I went back out to test the chlorine after 2 hours to make sure it was still in the appropriate SLAM target levels for 30 CYA, and I was shocked to see a 0.5 to 1 PPM of Free Chlorine. The test only required one drop to go from pink to clear. I tested a second time, and even compared against test strips I had left over from last year, all the same results.

Upon further pool school research, I stumbled upon Ammonia problems in the pool at opening. I'm concerned I possibly screwed up as I added 30PPM of CYA and it could be getting turned into Ammonia. I went to the store to prepare to break the lock, and I have 29 gallons of Liquid Chlorine on hand. Before taking next steps, I just wanted to confirm that adding such a large amount of chlorine to the pool won't be harmful. My understanding is that I should raise the FC by 10-12PPM every 30 minutes until it holds at less than a 50% loss after 30 minutes. Does this all have to happen synchronously, or can I break it out over the next couple of days?

Despite the FC being used so quickly, there have been noticeable improvements since opening - pictures attached.

PH: 7.2
CYA: 30
FC: 0.5-1
TA: Untested before SLAM
CH: Untested
 

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No, I do not suspect ammonia. You're just eating up chlorine like candy with that heavy algae. It will require a bit ore babysitting on day one, but you'll break through. Test a bit earlier this time and eventually it will spread out.
 
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Hi TFP, I've been a long time lurker and this year decided to go all in on the TFP methodologies after two years of pool store ambiguity and hardships. I read pool school multiple times, and got started opening my pool on Wednesday.

I ordered my TF-Pro test kit, practiced with the samples, then got started. After opening day, PH was below 7 and CYA was below 30 (assumed to be 0) as I could fill the entire view beaker with the black dot clear as day. I then started to follow SLAM procedure, raising PH to 7.2, and adding socks with CYA to raise it to 30 CYA. I retested CYA after dissolving and circulating for a day, it measured just shy of 30 PPM. Great, time to start the SLAM, so I thought. The pool opening condition was rougher than last year, definite algae bloom and dark green color to it from our mild winter.

I vacuumed the majority of visible debris to waist. Then, I added my initial shock - 4 gallons of Liquid Chlorine to raise my 30k gal pool to roughly 12.8 PPM FC. Immediately after, I brushed a whole lot to suspend the algae and circulate the chlorine, pump running 24/7 at this point. I went back out to test the chlorine after 2 hours to make sure it was still in the appropriate SLAM target levels for 30 CYA, and I was shocked to see a 0.5 to 1 PPM of Free Chlorine. The test only required one drop to go from pink to clear. I tested a second time, and even compared against test strips I had left over from last year, all the same results.

Upon further pool school research, I stumbled upon Ammonia problems in the pool at opening. I'm concerned I possibly screwed up as I added 30PPM of CYA and it could be getting turned into Ammonia. I went to the store to prepare to break the lock, and I have 29 gallons of Liquid Chlorine on hand. Before taking next steps, I just wanted to confirm that adding such a large amount of chlorine to the pool won't be harmful. My understanding is that I should raise the FC by 10-12PPM every 30 minutes until it holds at less than a 50% loss after 30 minutes. Does this all have to happen synchronously, or can I break it out over the next couple of days?

Despite the FC being used so quickly, there have been noticeable improvements since opening - pictures attached.

PH: 7.2
CYA: 30
FC: 0.5-1
TA: Untested before SLAM
CH: Untested
Welcome! Even if it is on unpleasant terms.

A couple comments:
1. Do the TA and CH tests. If the CH is overly high (likely wont be) you’de want to decide between just dumping the water and trying to live with it.
2. The FC test doesnt provide a range. Its either 0.5 or its 1. Dont complicate it trying to guess. If 1 drop didnt make it go clear but the second drip does, its a 1.

Ill let someone else comment in detail on the ammonia test, but it generally will hold zero chlorine if you have ammonia. Theres no 50% thing needed. In the future, open your pool earlier so uou dont have to go through that kinda mess.
 
No, I do not suspect ammonia. You're just eating up chlorine like candy with that heavy algae. It will require a bit ore babysitting on day one, but you'll break through. Test a bit earlier this time and eventually it will spread out.
Thanks - Thats what I'm hoping for (especially seeing progress on the color change as well), fingers crossed! I'll babysit it very closely this evening when I can get back to shocking it.
 
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Welcome! Even if it is on unpleasant terms.

A couple comments:
1. Do the TA and CH tests. If the CH is overly high (likely wont be) you’de want to decide between just dumping the water and trying to live with it.
2. The FC test doesnt provide a range. Its either 0.5 or its 1. Dont complicate it trying to guess. If 1 drop didnt make it go clear but the second drip does, its a 1.

Ill let someone else comment in detail on the ammonia test, but it generally will hold zero chlorine if you have ammonia. Theres no 50% thing needed. In the future, open your pool earlier so uou dont have to go through that kinda mess.

Thanks, I will test for those two to confirm this evening.

I appreciate the advice! I will try next year, though we do run freeze warnings just about up until mid May so timings a bit challenging. This winter we had tons of rain and warmer weather, and I probably didn't dedicate to enough winter defense (other than having a good safety cover on).
 
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