Need some help with chemicals

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Kittson

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Jul 17, 2017
17
Thief River Falls, Minnesota
Hi! I am just getting started with our pool. Pool stats are in my signature.

Last night we filled it with city water from the fire hydrant. I put the sand pump on filter without backwashing first, so there is some sand on the bottom of the pool. edit to add: I caught it after about 30 seconds and shut the pump off. I then backwashed, turned off, rinsed, turned off, and then it's been filtering ever since (about 24 hours now.)

I did a test today with strips from a friend. The test strips are Hach brand AquaCheck 7. I am currently waiting for the HTH 1173 6-Way test kit, but it won't be here until Thursday.

Here are the results:
FC: 20
PH 8.4
TA 120
CYA 100?!?!?!

I put in 1 gallon of 12.5% Chlorine yesterday and another gallon today. I have a sock with 17 oz of CYA hanging on a noodle near the output of the pool.

Can I trust the CYA reading right now? Our pool is CLOUDY and not looking so great right now. Should I just sit tight until the other test kit comes?
 
Just a heads up, that kit only tests for Total Chlorine, not Free Chlorine, and maxes out at 5ppm. When testing your pool, you need to know how much Free Chlorine (FC) and Combined Chloramine (CC) are in your pool. FC is the Chlorine that's free to sanitize your pool, and CC is a measure of how much organic matter is in your pool. You want FC to be in balance with your CYA according to the chart in my signature, and CC should always be 0.5ppm or less.

The recommended test kit is the TF-100 (link in my signature), that tests for everything you need to balance your pool.

Also, test strips are horribly unreliable and its not recommended to make adjustments based on the results of them.

Assuming that test strip results for CYA are even in the slightest way close to accurate, you need to remove that CYA sock now! Your CYA should be around 40ppm and can only be lowered by partially draining your pool. CYA that's that high will require a huge amount of chlorine to remain effective, and be extremely difficult to slam should you start having issues with algae.
 
And this is why test strips are worthless ... if you have not added any CYA, then it is 0.
17oz of stabilizer will only raise it to ~32ppm and that is after it is all dissolved.

You went WAY overboard of the chlorine. Each gallon is adding 31ppm of FC and with no CYA in the water, that could be damaging your pool. Starting a fresh pool you only want to add about 2ppm of FC until you get some CYA in it. Do not raise the FC above 10ppm any more.

So your high FC could be messing up all the results from the test strips ... just do not even bother with them.
 
City water does not have CYA in it, so unless you added 100 ppm of CYA in the last 24 hours your CYA is not 100. Just another example of the worthlessness of test strips. Why people insist on trusting them despite all the evidence... Er, sorry, that is a general rant not aimed at you ;)

I would say to sit tight and wait for the kit, but are you planning to run your pool as a temporary pool? Typically for a pool larger than 3000 gallons we recommend treating it like a permanent pool and getting a k-2006 or TF-100 to care for it. With the kit you are waiting on you won't be able to test FC or CC which is important in performing a SLAM to correct cloudy water. Running the pool as a temporary pool means dumping water when it gets cloudy since you can't SLAM properly.
 
Kittson said:
Hi! I am just getting started with our pool. Pool stats are in my signature.

Last night we filled it with city water from the fire hydrant. I put the sand pump on filter without backwashing first, so there is some sand on the bottom of the pool. edit to add: I caught it after about 30 seconds and shut the pump off. I then backwashed, turned off, rinsed, turned off, and then it's been filtering ever since (about 24 hours now.)

I did a test today with strips from a friend. The test strips are Hach brand AquaCheck 7. I am currently waiting for the HTH 1173 6-Way test kit, but it won't be here until Thursday.

Here are the results:
FC: 20
PH 8.4
TA 120
CYA 100?!?!?!

I put in 1 gallon of 12.5% Chlorine yesterday and another gallon today. I have a sock with 17 oz of CYA hanging on a noodle near the output of the pool.

Can I trust the CYA reading right now? Our pool is CLOUDY and not looking so great right now. Should I just sit tight until the other test kit comes?
Click to expand...
There's no way you have 100 CYA already. There is none in tap water. The test strip is just plain wrong.

I don't think you want to trust the pH reading with the FC so high.

The cloudiness could just be the dust from the sand filter blowing in. Shouldn't be algae so quick, not with as much bleach as you've added.
 
PoolMath says to lower CYA from 100ppm to 40ppm, you'd have to drain and refill 60% of your water. With an already high TA, and only 4,000 gallons in your pool, it might be best to just drain it and refill completely, and start over doing it right from the start. Again though, this is making the big assumption that those test strips are even remotely accurate.

EDIT: missed the part about having just filled the pool last night, sorry
 
Ok, thank you for your help. I am going to leave it alone until I get my better kit. I thought CYA would be impossible to mess up, since I followed the recommendations in Pool Math for the size pool that I have. Yikes, looks like I overdid the chlorine big time. :( Luckily that will go down on its own.

I have added CYA, 17 oz (weighed out on a digital kitchen scale) for a 4000 gallon pool.
 
Kittson said:
Ok, thank you for your help. I am going to leave it alone until I get my better kit. I thought CYA would be impossible to mess up, since I followed the recommendations in Pool Math for the size pool that I have. Yikes, looks like I overdid the chlorine big time. :( Luckily that will go down on its own.

I have added CYA, 17 oz (weighed out on a digital kitchen scale) for a 4000 gallon pool.
Click to expand...
That will get you to 30 CYA.

Now you know why we dislike test strips.

Have you read Pool School - Guide for Seasonal/Temporary Pools
 

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Richard320 said:
That will get you to 30 CYA.

Now you know why we dislike test strips.

Have you read Pool School - Guide for Seasonal/Temporary Pools
Click to expand...

Yes, I did read Pool School. I am just totally overwhelmed with all the numbers. I am not a math person and am feeling a lot of anxiety with learning this new stuff. I know I'll get it, I am just afraid of messing up - lol which I totally did anyway by ODing the chlorine.
 
Except for Chlorine (since it is burned up by the sun), its always best to add half the adjustment amount, then retest, then half the amount from the new results. Work your way up to the target so you don't over shoot. CYA and CH can only be lowered by partial draining and refilling, and TA can be lowered through a process of adding acid and waiting for pH to naturally raise back up (haven't done that myself, so let someone else give you some better instructions on that).

Making adjustments based on test strips is more like a blind guy trying to play darts. I made that same mistake at the beginning of the summer, and realized how bad the strips are when I took 3 tests back to back and got 3 different pH readings ranging from 6.2 up to 8.2. Found out when I got my TF-100 kit that the pH was below the minimum reading for the tester. Later bought a digital pH meter from the test kit site linked in my signature and found out my well water has a pH of 4.8, very far from the 6.2-8.2 the strips claimed.
 
You will get it figured out! Having the test kit makes a big difference. I spent a few weeks fighting algae, testing with strips. The pool cleared in about 5 days once I started using the test kit. Don't worry about the math. As long as your data is correct, the PoolMath page will tell you how much of each chemical you need to add.
 
Marie2375 said:
You will get it figured out! Having the test kit makes a big difference. I spent a few weeks fighting algae, testing with strips. The pool cleared in about 5 days once I started using the test kit. Don't worry about the math. As long as your data is correct, the PoolMath page will tell you how much of each chemical you need to add.
Click to expand...

Thank you Marie!! <3 I wish I would have had the kit from the get-go, but when the Fire Dept is ready to fill the pool, one says OK. :) One more day and the kit will be here. I will test tomorrow evening and update everyone with the numbers.

For the time being, I am going to backwash the sand filter pump this morning and then leave the pool uncovered until I can see where I'm at tomorrow.

Thanks again everyone!
 
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