Always low chlorine

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,012
Bedford, TX
You just need to test FC and CC.. CC's should be zero or close to zero.

I would not worry about pH just for the OCLT..

I assume you are using the powder to turn the sample pink the the drops to turn it clear...???

I would want to run the OCLT at a higher level than 4 ppm. More in the 8 to 10 ppm range to start.

Jim R.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
You just need to test FC and CC.. CC's should be zero or close to zero.

I would not worry about pH just for the OCLT..

I assume you are using the powder to turn the sample pink the the drops to turn it clear...???

I would want to run the OCLT at a higher level than 4 ppm. More in the 8 to 10 ppm range to start.

Jim R.
Thanks Jim. I did buy 4 gallons of chlorine today. Should I add 2 gallons tonight and then do my overnight test tomorrow night?
 

Fast7

Well-known member
Aug 8, 2018
180
Plainfield, IL
Add 1 gallon, make sure pump is on and SWCG is off, wait 30 minutes and test FC. That will be your starting point for OCLT. Next test needs to be done in the morning around sunrise.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Tested this am. Overnight drop in chlorine from 10 to 8.5. CYA of 30. Lower than last time but old results accuracy questionable as I was using strip. Sounds like a SLAM is in order.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Still unsure about CYA. Got out my Poolmaster 5 way test kit and it tested 80-90 ppm. Then retested with the Taylor k-2006c. I follow the procedure adding reagent to water. It’s mildly cloudy. Add to comparator and view from top to watch black dot disappear. Seems very subjective. I still think I am close to 30 as over 17k gallons, 1 gallon of 10% chlorine took me from 4-10ppm in the pool last night. Is 30 CYA too low to slam? How much fc am I aiming for to start
 

Mr Bruce

TFP Guide
Mar 24, 2014
2,438
Greenville, SC
Look at this chart. First you find the row with your CYA. It has your min, target and SLAM numbers. Then use the pool calculator to determine how much chlorine to add.

For what it's worth, the CYA test needs to be done with your back to full sun, vial at waist height. Just noting your location and what time it is.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
I’ll test CYA in an hour or so as mentioned. Sorry for all the newbie questions. Struggling with both your links. When I go to your first link the min CYA for salt pool is 60 with an asterisk. I’m possibly half that and there are no values given. On the second link I don’t see the option for 10% sodium hypochlorite to adjust my FC. thanks for your time
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,012
Bedford, TX
Terry,

If you are going to SLAM, the lower the CYA the better... Once you get the algae cleaned up, then get your CYA back up to 70 or so....

When you SLAM use the non-saltwater part of the chart to see what your SLAM FC level should be... Follow these instructions to the letter... SLAM Process

As a side note... if your CYA was 30 or less, there is no way that your SWCG would have been able to keep up... This is the main reason that the required CYA for saltwater pools is so much higher.

Thanks,

Jim R.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Terry,

If you are going to SLAM, the lower the CYA the better... Once you get the algae cleaned up, then get your CYA back up to 70 or so....

When you SLAM use the non-saltwater part of the chart to see what your SLAM FC level should be... Follow these instructions to the letter... SLAM Process

As a side note... if your CYA was 30 or less, there is no way that your SWCG would have been able to keep up... This is the main reason that the required CYA for saltwater pools is so much higher.

Thanks,

Jim R.
So correct me if I am wrong here. CYA is 30. 17k gallons. I’m at approximately 8ppm chlorine now. To slam I need 12. By my calculations it’s .67 gallons of 10% liquid chlorine.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Ok thx. So I would like to start before leaving for work. I’ll unplug the swg. Run pump continuously through process. I have a variable speed. What’s a good RPM? I’ll add my chlorine. Checking min twice a day to maintain 12ppm. Once I no longer have overnight drops I’m done with the slam.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,012
Bedford, TX
Since the CYA test is so subjective, I always recommend moving up to the next CYA level and using that SLAM number.

You don't need to be perfect with this, as long as you get above the recommended amount.

Edit.. your basic plan sounds good to me...

Thanks,

Jim R.
 

IceShadow

Gold Supporter
Jun 8, 2019
1,063
Milwaukee, WI
Since the water is clear the pump is just running to circulate around the chlorine and make sure it gets everywhere. You're not filtering out a ton of dead algae like someone with a cloudy pool. RPM on the low side should be fine.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Ok folks. Ready for next steps. Passed the overnight test. No drop in FC and no CC. Pool is currently at 13ppm chlorine. CYA 30. PH 7.9. SWG off. What is the best order to get things in check. Let the sun bring down chlorine to 5? Won’t take more than half the day here. Then kick in SWG and work on bringing up CYA levels? How fast and best way to bring them up to 70? Thx!!
 

gonfishin

Gold Supporter
Jun 13, 2017
282
Rochester, MN
Your pH reading is likely off due to FC over 10. Let your chlorine drift down to 10 or less, then test pH again.

If you’re confident your SLAM is done, you can start raising your CYA by adding the appropriate amount in a sock suspended in the pool before the chlorine drifts down. Adding stabilizer will also reduce your pH some.