Help needed with pool chemistry

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richardmac64

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Jul 16, 2014
21
Evansville, IN
Hi all, been lurking in this forum for a couple years now. But now need some help. Not sure what to do.
Pool has been clear until last week and became very cloudy where you couldn't see the bottom. Took water sample to pool store and they said I had no chlorine and salt level was low. Left with pool shock. Water didn't clear up in a few days. Came back to this forum and started looking at Slamming info.
I've been using a LaMotte 2056 ColorQ Pro 7 Digital Pool Water Test Kit, but don't really know if test are accurate. They never match what the pool store says.
It does tests for FCL and TCL and my results both showed Hi, (so much for a digitial tester, I guess 9.99 is the highest it goes).
I've added 12 gallons of pool shock water never cleared up, tests still show Hi.
So I stopped and order the TFTest kit recommended hear. It arrived today. Here are the results and pool info

18K fiberglass pool with SWG
FCL = 13ppm
CCL = at 100 drops it still never changed back to clear (is this possible)
ph = 6.8
Ta = 110
CYA = 45
CH = I got 650, don't know if I did this right. The ColorQ tester shows 250

Also I did start adding some DE to my sand filter 3 days ago and the water is clearing up, I can see the bottom in the deep end now.

Not sure what to do with the CCL being so high. Do I start the SLAM process up again? What shock level do I need to get at?

I'd appreciate any help that I can get on this.

Thanks
 
Welcome to TFP!

I'm not sure what you are referring to here, CCL = at 100 drops it still never changed back to clear (is this possible). If you are trying to measure CC, combined chlorine, then it seems you are not doing something right with the test. Tell us what reagents you are using to run this test.

The pH needs to be increased but it is difficult to say how much with the FC above 10 ppm.

What chemicals have you put in the pool and what is the color of the water?
 
I've just added pool shock (12 gallons). Water is still cloudy, getting clearer though. Don't know if the DE added to the sand filter, or just on its own.

For the chlorine test I did the following
10 ml of pool water in cylinder
1 scoop of R-0870 powder and mixed (turned pink)
R-0871 until clear (26 drops) = 13ppm FC
add 5 drops of R-0003 (turns pink again)
add R-0871 and stopped adding at 100 drops
 
If you have read around here much you have probably seen that not much credence is given to pool store testing. But, not many like the LaMotte ColorQ either.

Good choice on the TF-100. Time to SLAM you r pool.

You should read the directions on SLAMing your pool in the How To section of Pool School and follow that procedure completely to the end.
 
How big is your pool? You might put your pool information in your signature line so we have a better idea what we are working with.

12 gallons sounds like a lot of shock to be adding at any one time unless you have a very large pool or your CYA is very high.

How long have you had your test kit? Seems something isn't right.. with the CC part of your test. I certainly wouldn't go with the pool stores tests whatever you do, they are notoriously inaccurate. If you have had the test kit for awhile, it might be worth re-stocking some fresh reagents as they may not be as accurate as they once were.

DE will help to clear up some of the finer particulates in the water but will wash out when you backwash.

Salt is not necessary in a pool unless you have a SWG (salt water generator). Some also use it because they like the way it makes the water feel.

I would check the pool calculator with all of your pool information and keep your pool at SLAM value until you meet all of the criteria for SLAMming. It may take awhile, patience is key!
 
richardmac64 said:
I've just added pool shock (12 gallons). Water is still cloudy, getting clearer though. Don't know if the DE added to the sand filter, or just on its own.

For the chlorine test I did the following
10 ml of pool water in cylinder
1 scoop of R-0870 powder and mixed (turned pink)
R-0871 until clear (26 drops) = 13ppm FC
add 5 drops of R-0003 (turns pink again)
add R-0871 and stopped adding at 100 drops
Click to expand...

Seems like you are doing the test correct, and you have an extremely high CC value. I'll let some of the more experienced experts handle this one.
 
Just to make sure I did everything correct I ran the tests again. Here are the results

FC = 12.5
CC = 53
TA = 110
CYA = 60
CH = 360

So from this I need to SLAM and keep shock levels at 24 until CC < .5. (this is a SWG pool)
How do I figure out how much chlorine to add to get to 24. (18000 gallon fiberglass)

The gallons of shock I've been buying is 10% sodium hypochlorate.

Thanks
 
Use Pool Math to figure out how much chlorine to add to get to your SLAM level.
In your first post your CYA was 45. Now your CYA is 60. Did you add CYA or testing error ? It matters for your FC SLAM level.
What does your water look like ? Visible algae ? ?
 
I didn't add anything, so I'm assuming testing error. These new bottles get bigger drops sometimes it seems.
No algea, never have seen any, just last week it turned cloudy.

I didn't know pool math did all this. It is pretty neat. Says I should add 253 ozs of 10% chlorine to get to 24.
Add then I just keep it there until CC is < .5
 

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Pool math is your friend !!
You need to maintain your SLAM level by testing FC every hour if you can and bring it back up when FC falls below SLAM level. When your FC holds longer you can back of on testing some. Every two hours. Then less as FC holds longer. Make sure you read the SLAM Process and follow it to the T.
Your done when
1 water is crystal clear.
2 you have CC of 0.5-0.
3 you can pass the OCLT Test.
 
When adding the powder are you using a "heaping scoop"? It should be about the size of two scoops if you leveled off the scoops. It's ok to be slightly over on the amount of powder. I'm curious to see how this turns out and if the CC value of 53 is really valid.
 
just did the test again with a big heaping scoop of powder,
FC = 13
CC = 50

Not sure what happened to make the water cloudy. Talked to a few other people and their pools ended up cloudy as well during the same period.
I do live in a rural area, but there were no spraying in the fields and I always keep the cover closed. My uncle took a sample to a pool store and they told him is PH was low and calcium, so he did that and his cleared up. Not sure about the other person.

I'm going to start the SLAM process, but if anybody has any other thoughs/suggestions I'll be glad to try.
 
Before you do anything else, adjust the PH up to at least 7.0. PH levels below 6.8 can read as 6.8, so there is no telling just how low the PH might be.

You should have an OTO chlorine test, inside the blue K-1000 kit that comes with the TF100. It would be interesting to know what the OTO test does. If the FAS-DPD test is correct, the OTO test should start a brilliant yellow, perhaps with some slight orange tint, and then turn orange, then red, then brown. If it does something else there may be something interfering with the FAS-DPD chlorine test.

When doing the FAS-DPD test at very high FC and/or CC levels, you need to move through the test fairly quickly, adding drops at something like one drop a second through most of the test. You can slow down when the pink starts getting pale so you don't overshoot, but you need to complete the test fairly quickly. If you take too long you can get false high results.

From the description, the CC level must be quite high, certainly at least 30, but it is possible it is noticeably below 53.

You can do the test with just 5 ml of pool water, and each drop will count as 1 ppm. That will allow you to complete the test more quickly and hopefully avoid this issue, as well as saving on reagents.

CC levels that high with non-zero FC levels are quite unusual. It is certainly possible, but we don't run into a case like this more than once every few years.

One question, have you been using any non-chlorine shock products? MPS, a common non-chlorine shock, can read as CC on the test.
 

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