Combined Chlorine Craziness

[applebag]

I'm at my wit's end here... I've been chasing a combined chlorine problem for about a month.

20,000 gallon pool.. water only just slightly cloudy looking down to the deep end
DE Filter
In-ground
Vinyl liner

FC 0.64
CC 5.31
TC 5.95
CYA 77
Ph 7.8
TA 110
CH 146
68 degrees

I'm hesitant to shock it again because every time I do, the combined chlorine level spikes. I'm worried about throwing everything completely out of balance and causing a bigger problem by adding too much shock. Any guidance is greatly, greatly appreciated.

 

[Mike1162]

Most likely you haven't been keeping the chlorine level high enough for the level of CYA you have.
https://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

Get some liquid chlorine (aka bleach) & bring the chlorine level up to shock level. The pool math link above will tell you how much to use.

- - - Updated - - -

Oops - Here' the link for the SLAM process you'll be following.
https://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl
What kind of test kit do you have?

 

[Richard320]

Bleach is an oxidizer. So is fire. So bleaching the pool is chemical combustion.

When a fire smokes, it's because either a) it's not hot enough or b) it's short on oxygen. What do you do? Blow on it. It starts to get hotter and the smoke pretty much disappears.

CC is like the smoke from the bleach fire. If you're getting a lot of CC, you need to turn up the heat by blowing on it. Which means: more bleach. Yes, you'll get some "smoke" initially, but then things will speed up and burn all that ash and soot and it will go away.

Not chlorinating because it makes more CC is just inviting whatever is in the pool grow more, so you'll end up with more CC when you add chlorine again.

 

[duraleigh]

What are you using to "shock"?

How are you testing?

 

[applebag]

I got a fever! And the prescription is more bleach! Hard to go wrong with that meme.

For testing, I've been taking samples in to the pool store where they run it through their computer. I have test strips that I use for rough estimates.

I've been using the 3-inch tabs in the chlorinator and pretty sure I've been using CalHypo bags for shock. I ran through the Pool Math calculator and it's saying I need about 9 gallons of bleach to get to 30ppm FC.

 

[applebag]

I've bought ten gallons of 6-7% bleach. How long should I maintain a FC level of 28?

 

[mknauss]

You can not do a SLAM without a proper test kit - sorry. The Pool Store tests are not good, nor are they available every hour to start and several times a day at the end of your SLAM. The links in Post #2 are for the SLAM. You do not add once and forget.

You will need to decide if you want to follow what we at the forum can guide you in, or to use the pool store. Mixing them will lead to frustration and failure.

Take care.

 

[applebag]

You can not do a SLAM without a proper test kit - sorry.

Can you point me in the right direction for a proper test kit?

 

[borjis]

Taylor K2006c or TF-100 from tftestkits.com

 

[applebag]

On it! Thanks!

 

[planoattorney]

Applebag,

I just got the TF-100 today. Pretty impressive box of stuff and on advice I saw elsewhere on this forum, I added the Speed-Stir. You want the Speed-Stir!

I am no expert, in fact, pretty much ended up on this forum the same way you did, chasing chlorine following bad advice from the kid at the local pool store - how was that explained to me here . . . I was going to my local drug dealer and asking if I had an addiction, he says "you got cash" of course I got cash, so he says "you got no problem". Seriously, I wound up here because like you I kept adding chemicals and did not get any result only to learn that my CYA was so high, it was binding the chlorine - so I would add tri-chlor which added more CYA which bound up my chlorine and the only thing that survived was the green water.

I am still trying to wrap my grey-matter around the relationship of CYA and chlorine though. I gather it is like sun block, your pool needs it to keep the chlorine from burning up in the sun but some reason if it gets too high it keeps the chlorine from working. Maybe I should think of it like beer - a bar with no beer is boring and can't keep customers, but too much beer and the customers don't get anything accomplished, now if I can just find a thread to help me determine at what point my pool's BAC is too high.

 

[Richard320]

Applebag,

I just got the TF-100 today. Pretty impressive box of stuff and on advice I saw elsewhere on this forum, I added the Speed-Stir. You want the Speed-Stir!

I am no expert, in fact, pretty much ended up on this forum the same way you did, chasing chlorine following bad advice from the kid at the local pool store - how was that explained to me here . . . I was going to my local drug dealer and asking if I had an addiction, he says "you got cash" of course I got cash, so he says "you got no problem". Seriously, I wound up here because like you I kept adding chemicals and did not get any result only to learn that my CYA was so high, it was binding the chlorine - so I would add tri-chlor which added more CYA which bound up my chlorine and the only thing that survived was the green water.

I am still trying to wrap my grey-matter around the relationship of CYA and chlorine though. I gather it is like sun block, your pool needs it to keep the chlorine from burning up in the sun but some reason if it gets too high it keeps the chlorine from working. Maybe I should think of it like beer - a bar with no beer is boring and can't keep customers, but too much beer and the customers don't get anything accomplished, now if I can just find a thread to help me determine at what point my pool's BAC is too high.

 

[applebag]

I got my TF-100 and today is shock day! How long should I maintain a FC level of 28?

Thanks!

 

[Richard320]

I got my TF-100 and today is shock day! How long should I maintain a FC level of 28?

Thanks!

You are done when:
CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test (ie overnight FC loss test shows a loss of 1.0 ppm or less);
And the water is clear.

When all three are true, you are done SLAM Processing and can allow the FC to drift down to normal levels.

 

[applebag]

Thanks a million! Crazy about this internet. Not sure how folks shared info easily before it.

 

[applebag]

Okie doke - pH was at about 7.5, FC was nil, CC was 0.5ppm. I've added the recommended amount of bleach and started the SLAMing process.

How soon should I test for FC and CC? I'm assuming I test every hour after that.

I'm going to grab a few more bottles of bleach, in case I need to maintain for a while.

 

[Flying Tivo]

Hello:

You need to run the full set of test from the TFT and post like this:
FC
CC
PH
TA
CH
CYA

As you can tell by now you did not have a CC problem, it was just a Pool $store problem! When in SLAM mode you need to test every 1-2 hours depending on FC consumption, after it start to hold you can test every few hours. You really need the CYA number to know your slam level of FC, if not the slam is not going to work.

Felipe

 

[applebag]

Felipe,

I cross-checked the CYA pre-SLAM on the chart mentioned above to determine what FC I needed to hit (it had changed slightly since my original post). I'll test in 30 minutes to see where the FC and CC levels are! Thanks!

 

[domct203]

During a SLAM focus on FC. You can't check pH accurately when FC >10ppm & CYA should not change unless you are doing a lot of backwashing/top offs.

 

[applebag]

I just tested the FC and it was at about 14 instead of 25! I counted the amount of bleach correctly, but my accuracy of some other measurement must have been off. Or maybe I need to pull a water sample from deeper than six inches. I went through the pool calculator and added some more bleach. I'll test again in an hour.