New Home, New Pool

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#1
Hi, all. I purchased a six year old home with a small kidney shaped pool a week or so ago. I've never had a pool before and so this is new to me. We had a few freezing days here and so we've kept main pool pump running (and SWG) just to address the freeze, but I finally received my TF-100 test kit and so I performed my first tests this morning (Happy Thanksgiving!). Results were as follows:

FC 26.5
CC 0
TC 26.5
PH 8.2 (or higher -- off the chart)
TA 120
CH 275
CYA 20

Given what I've read, I went ahead and dropped the SWG output from 60% to the lowest setting of 20%. I also happened to have some muriatic acid and so I added the suggested amount using the pool calc template here. It's circulating as I type.

In any case, I'm trying to get this thing under control. I've ordered some "trippers" for the two Intermatic mechanical switches which control the main pool pump and the booster pump for the Polaris vacuum. That should allow me to set some standard times (and therefore standard amount of chlorine addition via SWG). I haven't read enough to tell me how to address some of the other tests which are out of range, but wanted to post this here before I leave for Thanksgiving festivities.

Any and all comments are welcome! Thank you.

gk
 

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
#2
Welcome to TFP and Happy Turkey Day !!
First your FC level is very high. Have you added any other chlorine source besides your SWG ? Did you use the 10 ml sample and each drop is worth 0.5 ppm ? You can just let that FC level drop down on its own if the test result is true. It may take sometime but it will drift down. You can turn your SWG off until it does.
What is your water temp ? Is your pool closed, covered ? SWG's won't produce chlorine when the water temp gets cold. Low 50's I think. You would have to manually add chlorine at that point via bleach.
Second your PH test is invalid with your FC that high. The test will read a false high with FC level's of 10 or more. So just let your FC drift down to below 10 and retest.
Third your CYA level is low. For a SWG we recommended that level to be 70-80. If your water is too cold for your SWG to function you can bring that level up to 40 and use bleach for your chlorine. Your target FC range will be 7 and never below 3. Then in the spring you can raise your CYA level up to 70-80 for your SWG. There are some good articles in Pool School on SWG's.
Your TA is a bit high also but with keeping your PH In check that will also start to lower that level albeit slowly. For a SWG that level should be around 60. Here is another way to lower TA. How To Lower TA
How much reading in Pool School have you done ? I'm going to suggest you do some reading to get a grasp on your water chemistry and what your test results mean and how to manage your levels.
Here are a few good articles to start with.
ABC'S Of Pool Water Chemistry
How To Chlorinate Your Pool
Recommended Levels
When you have anymore questions don't hesitate to ask. 😎
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
35,961
Tallahassee, FL
#4
Welcome to TFP!

You are so far ahead of the game with the test kit you will be fine!

Jeff has you going in the correct direction. It is a learning curve but so worth it!

Let us know if you have any questions or need any guidance.

Kim
 

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#5
First your FC level is very high. Have you added any other chlorine source besides your SWG ?
I didn't add any other source of chlorine. I did add salt when my Intellichlor told me the salt concentration was low (this was right when I purchased the home). One thing I did note to myself is that the Pentair IC40 literature says it's designed for pools with up to 40k gallons and mine is a lot smaller than that. With excessive use I guess it might be easy to heavily dose this pool with chlorine if it was running for long periods of time.

Did you use the 10 ml sample and each drop is worth 0.5 ppm ?
Yes. The 10ml took 53 drops. Ouch. As I added each drop I knew I was way above the target levels. I just read that one more push of that button would have gotten me to 0% on the SWG so I'll do that and monitor the FC as it falls. :)

What is your water temp ? Is your pool closed, covered ?
I don't have a thermometer, but the short answer is "cold". The pool is outside and is not covered. I'll get a thermometer and read up on my Intellichlor to see if it's working or not.

Second your PH test is invalid with your FC that high. The test will read a false high with FC level's of 10 or more. So just let your FC drift down to below 10 and retest.
Oops. I hope I didn't add too much acid... I guess we'll see.

Third your CYA level is low. For a SWG we recommended that level to be 70-80. If your water is too cold for your SWG to function you can bring that level up to 40 and use bleach for your chlorine. Your target FC range will be 7 and never below 3. Then in the spring you can raise your CYA level up to 70-80 for your SWG. There are some good articles in Pool School on SWG's.
I'll get some cyanuric acid and adjust the CYA. I'll also get to readin'! :)

Thanks for the links! I'll dig in.
 

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
#6
That's a good thing your SWG is oversized for your pool. It'll cut down on your runtime and the SWG won't have to be set as high. Bigger is better in this case !! 😎
 

Divin Dave

TFP Expert
LifeTime Supporter
Oct 2, 2013
5,189
Longview, Texas
#7
Hi gk
the chlorine only goes into the pool while the pump is running. So, depending on how long the pump runs each day, combined with a high % output on a IC40, being used on a 9K gallon pool, and add some 'cold' water to the mix, its conceiveable to me the FC could get pretty high over a period of several weeks.

The colder the water, the less chlorine the pool uses because the stuff the chlorine is there for just doesnt like cold water. (I consider cold water to be about 65ish and below). As a FYI on the IC40, when the water gets down to about 50 degrees, the Cold Water light will get lit up and all the other lights on teh IC40, will go off. It turns itself off, so dont freak out if that happens.
 

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#8
That's a good thing your SWG is oversized for your pool. It'll cut down on your runtime and the SWG won't have to be set as high. Bigger is better in this case !! ��
Good to know. I've got some experience with process controls in the chemical industry and sometimes "too big" is a problem...
 

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#9
Thanks to everyone with the replies! I'll try to get a photo of the pool sometime. The volume calc for the pool is a bit problematic given its shape and the "steps" at various areas, but I was hoping to use the calc template to eventually "zoom in" on the volume.

I guess I should have stated, but I do have the magnetic stirrer for my TF-100 and so at least I don't think inadequate mixing could be an issue.

Thanks again!
 

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#10
Just a quick update.

The pool's water temp as of this morning is a balmy 66 deg. F. It has warmed up over the past few days, but I imagine the pool temp lags significantly with ambient.

I performed the quick chlorine and pH tests this morning with similar results. I've had the SWG output at zero since Thanksgiving. I'm not going to bother running the higher resolution chlorine test until it comes into range on the quick one.

I just received my cyanuric acid, so I'm going to add half of what pool calc says and retest later in the week.

Thanks for reading.

gk
 

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#12
I put about 3 lbs of cyanuric acid (solid) in a hose sock and it's been in my skimmer for a few days now. I can lift the sock and very small granules of the acid will exit through the sock pores. I'm just surprised it's taking as long as it is to dissolve into the water. Will probably take over a week at this rate. Not a problem -- just an observation.
 

MarianParoo

Well-known member
Aug 16, 2014
4,615
Northern IL
#13
I have to say that I am very impressed with your knowledge of pool chemistry, having a signature line, etc.

For a first time pool owner, you are way ahead of the curve! Congrats, and best of luck!
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#15
Colder temps will take longer to dissolve the CYA. Some brands have finer grains than others, just squish that sock whenever you get a chance and it will go.

If you can find any paperwork from the installation of the pool, perhaps you can contact the builder and figure out a more exact volume for the pool. You could also get a good estimate using a chemical addition test, which you're actually doing right now. 3 pounds of CYA should raise your CYA by 40. If it only raises it actually by 30 you know your volume is higher and can calculate the volume based on that actual ppm level raised.

Welcome to TFP! :wave:
 

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#16
No, I haven't been running it 24/7. Maybe I should do that. I've got my switches set to run twice a day for about 3-4 hours. Sometimes I have turned it on manually. I figured the cooler temps weren't doing me any favors re: dissolving.

My CYA test results was between the 20 and 30 marks on the tube, but more toward the 20 so that's how I got there. Don't know if that 'extra' volume between the 30 and 20 mark represents a lot of error or not when I back-calculate the volume of the pool -- but I certainly will give it a shot!

@MarianParoo: I've no experience with pools, but plenty with piping systems and chemistry. :) As far as my signature line goes, I just read the instructions that told me to do so! :)
 

JVTrain

TFP Expert
Feb 3, 2014
5,080
Central Minnesota
#17
CYA isn't the best measurement for trying to calculate a pool volume because of the resolution and subjectivity of the test but it should give you a ball park number that you can work with. An FC addition test done at night with cool water would be a pretty good measurement as the test is much less subjective with a FAS-DPD test and can be done repeatedly (after you let the FC drop down over a few days). Raising it by 10 FC with bleach to test when it's at the low FC for your CYA level won't hurt anything. Just make sure you turn off the SWG when doing so!
 

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#18
Okay, so I'm reading and trying to think ahead. I'm going by the Water Balance for SWGs article. Here are my thoughts / ramblings and then a question:

After a quick chlorine / pH test today the FC appears to be close to the top number of 5 ppm (I think it's still higher, but getting closer) and the pH seemed to be close to 7.8.

As reported, I've added some cyanuric acid to start moving the CYA toward the recommended 70-80 for a SWG pool. It's recommended to wait a week or so after addition to re-test the CYA, so I'm going to do that. I'm anticipating having to add more acid but won't do that until I confirm with the actual CYA test.

It looks like I will be ready to add some "output" to my SWG to see where my FC lines out soon.

My TA was 120 ppm when I did my first series of tests which is much higher than the recommended 60 to 80 ppm. The 'water balance' doc says in very clear terms that this is important.

This article on how to lower TA says not to mess with it unless you are suffering from high rate of pH rising (unconfirmed on my end) or if you've got a high CSI putting yourself at a risk of calcium scaling. All I know is that my pH was definitely high when initially tested. I added some acid and it appears to be around 7.8. My CH was 275 which I thought was in range for my pool -- not sure if/how this relates to CSI, but I do know that the water in my area has very little hardness.

My pool has a "water feature" which is basically water over rocks into the pool. It's not crazy aeration, but it's not too bad either. What does this group think about the capability of my water feature to lower TA using the aeration method? And is it possible I don't have a compelling reason to worry about adjusting TA downward?

Thanks...!

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IMG_0832.jpg
 

zethacat

LifeTime Supporter
#19
I think the waterfall should be sufficient aeration but aeration does not lower your PH, it increases it. If you want to lower your TA, you bring the PH down to 7.2 and aerate it back up so that you can do it again. You can use pool math to determine what your current CSI is and play with the numbers to see how they all affect it. The temperature of your water can cause significant changes in CSI.
 

gkennedy3

LifeTime Supporter
Nov 21, 2014
19
Prairieville, LA
#20
Thanks, zethacat.

Performed second set of tests today.

FC 6.5
CC 0
TC 6.5
pH 7.8 (did not test again -- value from yesterday)
TA 110
CH 275
CYA (did not test because I added cyanuric acid recently)

Looking at the rate of FC loss (going from 26.5 to 6.5 over 9 days), right now I'm losing a little over 2 FC per day. I'm going to give it another day and then will start giving the SWG some output. Haven't done any calcs to figure out how much output is needed as I would have to define a lot of stuff I don't have time to do right now. Anyway, once I drop into the range of the quick FC test I should know if I'm falling off the low end or not and will make changes accordingly. I am running the pump probably more than I need to (3 hours at a time, twice a day), so I'm hoping a low output to the SWG is all that is required.