High CYA- Process after Draining Half my Pool?

[erodriguez215]

Hello community, I received my test kit over the weekend, results below.

FC= 12
PH= 7.8
TA= 130
CH= 380
CYA= 100+
CC= 0.5
Water Temp= 68F

According to TFPC method my CYA was way too high, I decided to drain half my pool 7K gallons. Interestingly during this process I measured and discovered I only have a 15,000 gallon versus a 24,000 gallon pool. Will be much cheaper to purchase a SWG system now. Enough ranting, I am confused about how much chlorine to add now that I replenished pool with fresh water. I am at work right now finished filling last night, I want to swing by store and pick-up liquid bleach. Should I begin the S-L-A-M process or test water and balance out. I plugged in some numbers on Pool Math and found if I wanted to shock at a level of 18 starting from 0 FC, I would need to add 3 gallons + 1 quart of 8.25% bleach. Seems kind of low for slamming. I read another post "1st SLAM" the guy is using 30 gallons of clorox and still cant raise the FC high enough for his 24000 gallon pool. I appreciate your help with this.

 

[jblizzle]

You need to test the water ... at least FC, pH, and CYA ... so that you know how to proceed with the SLAM.

Why do you think a FC of 18ppm is the right shock level? The required level is a function of your CYA as shown in the FC/CYA Chart.

You do realize you have to keep adding bleach to maintain the shock level right?

That person must be dealing with something in the water, like ammonia which will consume the FC quickly.

 

[tim5055]

Well, lets get another set of testing with all the new water.

Is there a reason you need to SLAM, like cloudy water, visible algae or it's a green swamp?

 

[erodriguez215]

My water is pretty clear, I just thought lets start off with a good S-L-A-M for sanitary purposes. Since replacing half my water thought I may need a stronger treatment.

Jbizzle I was playing with some numbers assuming my CYA dropped to 50 and FC was at 0 shock treatment according to CYA chart is at 20 FC. I was being conservative at 18 FC.

I will test my water this evening and post new results. Thanks

 

[jblizzle]

You want to maintain the FC at or just above the shock level, not below it.

 

[erodriguez215]

Just ran the numbers:
FC 6.5
CC less than .5
PH 7.6
TA 120
CH 280
CYA 45
Water temp 74

What next?

 

[jblizzle]

Lower pH and then follow the ShockLevelAndMAINTAIN Process

 

[erodriguez215]

Jbizzle I plugged in the numbers on pool math says everything is balanced do you still suggest slamming PH is the only number out of wack.

 

[Richard320]

Just ran the numbers:
FC 6.5
CC less than .5
PH 7.6
TA 120
CH 280
CYA 45
Water temp 74

What next?

You're almost there. A little acid to get pH to 7.2, let it mix half an hour or so, then jugs away! If you check the FC after the sun goes down and check it again tomorrow morning before it comes up, you might discover you've already passed all 3 tests and the SLAM is done. Wouldn't that be handy?

 

[erodriguez215]

My thoughts as well, I never slammed the pool, these are my numbers since refilling after draining. I am using the pool pucks right now but will be switching to bleach method. I have not done anything to my pool since refilling.

One question when testing CYA with K-2006 kit. Instructions indicate adding drops until black dot not visible. I have pretty good eye sight can see reminance of black dot completely goes away at 40 could barely see at 45 am I reading this correctly?

 

[jblizzle]

Dot should be completely gone.

 

[Isaac-1]

The CYA test is best done in full sunlight with the sun to your back, see this you tube video for guidance https://www.youtube.com/watch?v=NxaqoW-_MCs

 

[Richard320]

My thoughts as well, I never slammed the pool, these are my numbers since refilling after draining. I am using the pool pucks right now but will be switching to bleach method. I have not done anything to my pool since refilling.

One question when testing CYA with K-2006 kit. Instructions indicate adding drops until black dot not visible. I have pretty good eye sight can see reminance of black dot completely goes away at 40 could barely see at 45 am I reading this correctly?

I think you're getting your tests confused. The CYA test is 50-50 sample and reagent, and then you dribble it down into the view tube until the dot disappears



You DO understand that the pucks are why you had to drain your pool, right? Every single puck you add increases the CYA. http://www.troublefreepool.com/content/142-how-to-chlorinate-your-pool

 

[erodriguez215]

Yes, I did the CYA test 50/50 like the video.

I also realized the pucks were my issue with high CYA. Will be abandoning pucks getting bleach.

Thanks for all the help.