conflicting water test numbers

[keithpgdrb]

Hey all, new guy here. I have a ColorQ 2x for testing my water. took my water to the local trusted pool store to get my water tested. These guys are the best available in the area, even though they mostly try to push their chemicals on me. anyway, the results from them, and from my color q are pretty different in important ways.

Disclaimer: I have an automatic cover, and pulled water to test right after opening. then I left the pool open for an hour or so and used that water on my color Q.

Color Q numbers: water temp around 80-85 degrees
FC - 2.51
TC - 2.98
PH - 7.8
Alk - 123
adjusted alk - 98
CH - 447
CYA - 85

Pool Store: water temp around 78 degrees
FC - 2.5
TC - 5
PH - 7.8
TA - 120
adjusted alk 103
CH - 600
CYA - 55

what do you think? which Alk number to I use?
Thanks, and sorry if its too noob.

 

[Texas Splash]

"keith", welcome to TFP! @Jimrahbe can speak more on the ColorQ, but honestly I don't think the disparities in the TA is your biggest issue right now. The questionable CYA test is. I'll let Jim speak for the validity of a ColorQ CYA test, but you can almost certainly rule-out the pool store testing. They are never dependable.

Be sure to visit our Pool Care Basics page, and look for the "Test Kits Compared" section. If you have any questions let us know. Enjoy the forum.

 

[ajw22]

Welcome to TFP.

Use the Color Q numbers and stay out of Pool stores.

The PS alkalinity is adjusted with them subtracting 1/3 of the CYA. Adding that back in and they pretty much agree.

TA - Further Reading

www.troublefreepool.com

The ColorQ is ok except that it cannot test FC over 10 ppm. Which means it cannot be used for our SLAM Process

Also LaMotte actually measures Total Hardness and not Calcium Hardness, no matter what LaMotte calls it in their paperwork. Total Hardness depends on a lot of other hardness factors other than just Calcium. Total Hardness depends a lot on your local water.

Pool Test Kits - Further Reading

www.troublefreepool.com

 

[keithpgdrb]

I threw some info in my profile. I also ordered up one of the recommended test kits. I will test the CYA again today. I also read somewhere that CYA tests are also temperature sensitive. the pool sits around 85. but gets much hotter in the summer sun.

I Have an automatic cover. I was told that keeping it closed too much is bad. this seems true. yes? i've really only been opening it when we use it. which is mostly on the weekends.

Closing the pool mid October. If I'm going to have to do some draining and rebalancing, I better hurry up. pool party though next week. ugh.

 

[ajw22]

I also read somewhere that CYA tests are also temperature sensitive.

CYA Testing - Further Reading

www.troublefreepool.com

Cold Test Water Should be Room Temperature for CYA Test​

If the water temperature is below 70F degrees let the water warm up inside before you do the CYA test.

The standard instructions to mix for 30 seconds is not enough time when the water is cold. You can either mix longer, or allow the sample to warm up to room temperature. Best solution is to allow the the sample to warm up first and then shake it for 30 seconds.

Taylor Technologies has run the pH, total alkalinity, calcium hardness, free chlorine, and cyanuric acid tests on known standard solutions at approximately 104°F, 75°F, 60°F, and 40°F. Only at 40°F did the CYA standard solution test higher than its actual value (after accounting for test variability). All other tests were unaffected by temperature differences.

I Have an automatic cover. I was told that keeping it closed too much is bad. this seems true. yes?

You need to open the cover to let the sun burn off the CCs.

CC - Further Reading

www.troublefreepool.com

Closing the pool mid October. If I'm going to have to do some draining and rebalancing,

What do you think needs to be rebalanced?

 

[Mdragger88]

Keith,
If the water is room temp or above then the cya test should be accurate (as accurate as the color q can be)
For now, you should count your cya as 90 & chlorinate accordingly until your kit comes & you get an accurate cya reading FC/CYA Levels
your fc is currently too low. It is too low even if your cya was only 60. Dose with liquid chlorine now to get into target range for your cya.

Leaving the cover on traps cc’s which is probably the reason you are seeing that disparity between the sample taken immediately after removing the cover & the one later. To prevent cc’s from building up, leave the cover off a little while after swimming is done to give them a chance to dissipate. If you haven’t been using the pool for an extended period open the cover every now & then for a bit to let the cc’s escape. This should help prolong the life of your cover as well.

 

[keithpgdrb]

Keith,
If the water is room temp or above then the cya test should be accurate (as accurate as the color q can be)
For now, you should count your cya as 90 & chlorinate accordingly until your kit comes & you get an accurate cya reading FC/CYA Levels
your fc is currently too low. It is too low even if your cya was only 60. Dose with liquid chlorine now to get into target range for your cya.

Leaving the cover on traps cc’s which is probably the reason you are seeing that disparity between the sample taken immediately after removing the cover & the one later. To prevent cc’s from building up, leave the cover off a little while after swimming is done to give them a chance to dissipate. If you haven’t been using the pool for an extended period open the cover every now & then for a bit to let the cc’s escape. This should help prolong the life of your cover as well.

thanks man. I'll admit I'm confused about the relationship between stabilizer and chlorine. I thought chlorine should be kept between 2-4. the chart here implies min 4 up to 6.

I dont have any liquid chlorine, I do have powdered shock that I disolve with pool water before I add it. Unfortunately it is supposed to storm tonight, so I cant shock tonight.

I pulled a new sample just now and will check everything again. cover has been off for an hour or so.

 

[keithpgdrb]

New numbers. chlorine is low. it was open in the sun for a good amount of time.

FC - 1.47
TC - 1.84
CC - .37
pH - 7.8
Alk - 104
Adjusted Alk - 81
CH - 437
CYA - 76

 

[gingrbredman]

I Have an automatic cover. I was told that keeping it closed too much is bad. this seems true. yes? i've really only been opening it when we use it. which is mostly on the weekends.

As already mentioned, good idea to open it up and let it breath more often. As the temps begin to fall quickly at night around here, the cover is great for keeping that heat in, but the CCs as well.

I dont have any liquid chlorine, I do have powdered shock that I disolve with pool water before I add it.

Best bet is to go grab some, it is a far better choice than any powdered "shock". There is no real good use for the powdered stuff, the local stores around still have liquid chlorine on the shelves.

Unfortunately it is supposed to storm tonight, so I cant shock tonight.

You can add the right amount of liquid chlorine in spite of any rain or storms. You need chlorine ASAP

 

[wireform]

Don't worry about your CC but in your case you're skirting/flirting with algae with the low FC.

 

[ajw22]

Your CYA is high for a covered pool and your FC is too low for your CYA level.

What size IntelliChlor cell do you have?

What is your pump runtime?

What is your cell %?

You can use your SWG and get your FC up to 9 in day.

Forget about using your powered shock. You don't need more CYA or calcium in your pool.

 

[Bperry]

I thought chlorine should be kept between 2-4. the chart here implies min 4 up to 6.

It used to be the standard many years ago and is still often used by companies that don’t know better. Technically it still is a reasonable standard when there is no CYA in the water, but once CYA is added, that standard goes out the window.

 

[keithpgdrb]

Your CYA is high for a covered pool and your FC is too low for your CYA level.

What size IntelliChlor cell do you have?

What is your pump runtime?

What is your cell %?

You can use your SWG and get your FC up to 9 in day.

Forget about using your powered shock. You don't need more CYA or calcium in your pool.

My intellichlor usually runs about 8 percent. I leave the pump on 24/7. I can crank up the swg. I already turned it to 20 when I saw the low chlorine. I’ll look into the liquid shock. I have a bunch of powder that doesn’t have cya in it. At least I think. Pretty sure I looked for that. It’s the hth stuff.

 

[keithpgdrb]

sorry, double posted.

 

[keithpgdrb]

Salt generator is the pentair lc40

 

[ajw22]

8% gives you 1.1ppm of FC/day

20% will give you 2.8ppm of FC/day

I would up your % to 60% for 24 hours and raise your FC by 8.4 ppm. Then reduce it back to 8% and see which way your FC moves over a few days.

 

[Bperry]

My intellichlor usually runs about 8 percent. I leave the pump on 24/7. I can crank up the swg. I already turned it to 20 when I saw the low chlorine. I’ll look into the liquid shock. I have a bunch of powder that doesn’t have cya in it. At least I think. Pretty sure I looked for that. It’s the hth stuff.

If the powder doesn’t have CYA, then it has calcium which looks like you already have enough of that.

 

[keithpgdrb]

Ok. I bumped it to 60 percent. After the chlorine is back up. What should I do next?

 

[keithpgdrb]

If the powder doesn’t have CYA, then it has calcium which looks like you already have enough of that.

Dang. I assumed the shock would just shock. Not add minerals. Now I know why my calcium is higher. I’ll check the packaging.

 

[ajw22]

After the chlorine is back up. What should I do next?

Lower the SWG % to around 8% and find the setting that maintains your FC at 7-9 ppm.

I would do a Overnight Chlorine Loss Test with your SWG at 0 and see if it shows you have algae and need the SLAM Process.

Otherwise maintain your FC at 7-9 and pH in the 7's and let your CYA naturally degrade. With a covered pool you don't need more then CYA of 30-40. As your CYA comes down you can reduce your FC target following the FC/CYA Levels.