Chlorine Issues

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M

MLSaylor

0
May 15, 2011
11
I started using the BBB method last year and had no problems. This year is a different story. I've been fighting my pool since I opened it three weeks ago to maintain a FC reading. I am trying the shocking method right now described on this website, but don't know if it will ever work! I thought I had it yesterday, but I dropped to 0 FC while I was at work today, so I started again.

My water is clear. My CC is .5, but I am dropping about 5 ppm overnight. How long will this go on? I am adding chlorine tonight every 2 hours tonight to maintain 20 ppm. It dropped about 4 ppm in 2 hours this evening (with little sun). I am really afraid that I'll bleach my new liner. Any advice??

Here's my numbers using the TF-100 kit:
FC - 20 ppm
TA - 120
PH - 7.5
CC - 0.5
CYA - 50

20,000 gallon inground pool/vinyl liner
DE Filter
 
ML Welcome to TFP, it sounds like you are really close. I wouldn't worry about bleaching the liner, but your plan of attack tonight is sound, you can even bump FC up to the 22-24 range so that when you return in two hours the water is at orabove 20ppm (ie shock level).
 
With a CYA of 50 you won't bleach your liner at an FC of 20ppm. Keep in mind that it goes much faster the better you're able to keep it at shock level. But you already know that. You should make progress pretty quickly now. Keep it at shock level as often as you can and until you pass the OCLT.
 
I don't have anything to add to the advice the mods gave you, but I wanted to say that more than one of us have been there. Whatever is causing the problem isn't going to survive the chlorine and it will come to an end! Hang in there!!

Good luck!

-- Pete
 
Okay... I did my readings every 1-2 hours last night. I stayed above 21 ppm. Before bed I was at 22 ppm and this morning I was still at 21 ppm. I went up to 22 ppm before leaving for work at 8 am. By 4 pm when I got home I was down to 3 ppm. What is going on? I don't want to do this all over tonight to have it drop again while I'm at work. What should I do?

20,000 gallons/vinyl liner
inground pool
DE filter
 
:scratch: you are sure your CYA level is 50? Just to rule out any testing error, test your pool water's CYA again and then perform the same test on your tap water. The pool water should remeasure close to 50 and the Tap water test should remain clear.
 
I retested CYA. It still looks like 50 to me... I then checked with a test strip for a ballpark estimate, and it came up "low." I tested the tap water, and I could see through to the bottom.
 
Sorry...one more idea. Test TC with the yellow OTO drops, next to the PH vial...if FC is at 4ppm and CCs are 0.5 or below, the solution should be a nice solid yellow, not dark burnt yellow or orange as it would be with FC at 15+
 
Now the FC using the OTO drops is down to 0.5. PH is 7.2. So we dropped from 5 to 0.5 in about 2 hours. Any ideas what I should do? I'm afraid to start the shocking sequence again, because it will drop below shock level while I'm at work tomorrow. I'm spending a small fortune on bleach!
 

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Regardless, you will need to fix it with chlorine. Chlorine is consumed by only two things.....sunlight and organics in your pool.

Since you have (partially) protected your chlorine from the sun, then organics in your pool is the conclusion.

The only way to get rid of them is with more chlorine. That you drop below shock level is not a deal breaker but it slows the process.

Was your CYA at or near 50 when you opened the pool?
 
I just dumped 7 gallons of bleach in the pool to try again. That should get me above 20 ppm. Thanks for your help. I really appreciate it. This is just frustrating. I had this problem all the time before going to the BBB method. When I got a new liner last summer I switched to BBB and had a beautiful pool all summer. This is the first season that I opened the pool using BBB.
 
Hang in there. You'll eventually "kill" what is causing you this headache.

Since your CYA was low when you opened, some or all of it may have converted to ammonia. I don't understand why this opccurs but the result is it will take a really huge amount of chlorine to get the ammonia out of your pool

Richard (chem geek) and Jason are both very knowledgeable about this not-very-often phenomenon but it does exist and the only solution is lots and lots of chlorine.

Once the chlorine demand is met, your pool will setlle down nicely and consume roughly 2ppm daily. That'll make your pool chores much more palatable. :-D :-D
 
duraleigh said:
Since your CYA was low when you opened, some or all of it may have converted to ammonia. I don't understand why this opccurs but the result is it will take a really huge amount of chlorine to get the ammonia out of your pool
Click to expand...

What converts to ammonia, the chlorine because of a lack of CYA?
 
How did the pool store test for CYA? Was it a black dot based test, strips, etc.? Most of the time you will be more accurate than the Pool Store so I'm not sure if you should drain just yet. Some others with more experience will chime in soon.
 

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