Balancing pool

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weatherillgrp

weatherillgrp

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May 19, 2014
28
Cortez, CO
I just changed the water in a 18/36 Vinyl IG pool with 18,000 gal capacity. It has a 1/2 hp pump; sand filter; and pentair 300 Chlorine 3" tab feeder. When I first tested after the refill FC: 0, PH 7.2 and A: 120,

I used the pool math to determine what I needed to add to the pool. I use granulated Trichloroethane in addition to the 3" tabs of trichloroethane in the feeder. For the past three days I have added 10 oz in volume granulated Trichloroethane dissolved in a bucket and added to the pool. After the first application the next day my test readings were FC: 0, PH :7.1, A : 140. The third day ( today) the readings were FC: 0; PH 6.9 and A: 160.

I am aware that the trichloroethane can lower the PH. I just don't know what to do to get the FC up to a 4 reading, maintain a PH of 7.2 - 7.8 and the A below 120. Would appreciate any guidance you can give me. I read that because I have a vinyl pool I should not be concerned about CYA. Does the trichloroethane have it in it anyway.

Thanks
 
Welcome! :wave:

Trichloroisocyanuric Acid does indeed raise CYA and lower pH. It will also lower the TA.

The solution is to chlorinate with something that doesn't contain CYA -- bleach!

A vinyl pool is unaffected by low Calcium Hardness. It will still suffer if CYA gets too high.

You should be reading
http://www.troublefreepool.com/content/134-recommended-levels
http://www.troublefreepool.com/content/142-how-to-chlorinate-your-pool
http://www.troublefreepool.com/content/139-recommended-pool-chemicals

That should explain things better.

You will need to add chlorine every day, just like feeding a pet. And until you raise the CYA level up to a reasonable level, you will lose virtually all your chlorine to sunlight every day.
 
Okay, according to the pool math software I needed to put 107 oz. of 8.25% bleach in my water. I did yesterday morning. I ordered a TF-100 Test Kit on Friday and it will not be here until next week. In the meantime I am using test strips. The results from them are as follows this morning:

FC - 0
PH - 6.4
CYA - indicates low
TA -120

According to the calculations for FC I needed to once again put 107 oz. of bleach in the pool. I did that about 30 mins ago. Is the low FC levels because of the PH being so low? If so, should I attempt to bring up the PH prior to trying to increase the FC? How sson after putting the bleach in the pool can I check it again. Sorry but I am going to get this right. I can not wait to get the new test kit so I can be more exact.
 
No, the pH has nothing to do with the disappearing chlorine. But it should be raised anyway for eye and skin comfort.

Two things consume chlorine: sunlight and organics. With low CYA, you'll lose a whole lot really fast to the sun if the cover was open. So it could just be that. The ugly alternative is that something is growing in the water and the chlorine is being consumed in the killing of it. The way to be sure is to do an overnight loss test, which you can't until you get the kit.

Thirty minutes should be enough time to allow it to mix before retesting. If you brush vigorously all the way around, it should be mixed up even better, sooner.
 
I have kept the pool covered except for when I am checking for chemicals so I don't think the sun is consuming the FC. Also, last Saturday I drained the pool 80%. I can not drain it completely in fear of getting air under the vinyl floor. The water is crystal clear. So I just don't get why the FC has not come up with over 214 oz of bleach in the past two days.

Also, would you also tell me how to place my equipment info at the bottom of my thread as others have?
 
The other alternative is that your FC is so high that it's bleaching out the test strip! Try diluting the sample water with some bottled water (no chlorine) and see what the test strips say then.

To change your profile and/or signature, select "Settings" (top right under Pool School button). Scroll down (left side) to "My Settings" & select Edit Profile or Edit Signature. Tips
 

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weatherillgrp said:
what levels would be okay for FC and CYA with the cover?
Click to expand...

I have an automatic cover as well as a SWG. I keep my CYA aprox 55 which is a bit lower than usually recommended for a SWG but I lose so little CL with the cover that it works well for me. If anything I sometimes just leave the cover open on bright sunny days to burn off some excess CL. My SWG set to 5 or 10% at 8 hours run my CL rises more than necessary, heck sometimes I can turn it off for a week or more and still never get too low! You might find you also get some long term CL presence too with the cover even though you're using liquid chlorine.
 
Yesterday the grandkids where here for Memorial Day Picnic. They enjoyed the pool. After they left I checked the chemicals. They were:
TC .09
PH 6.8
TA 180

Since the PH was low I decided to increase in some. I calculated the need for soda ash with the pool calculator and it called for 8.1 #'s of product. Following advice I used less then suggested and mixed 5.3#'s and applied it in interval over had an hour. After an hour I checked the chemistry again.

TC: 2.8
PH: 7.7
TA 190

I was pleased that the TC and PH were up where I wanted them. TA was too high.

This morning I opened up and cover and was disappointed to see that the water was still clouded as it was after I hades the PH UP. I checked the chemistry again and it was as follows:

TC: .9
PH: 6.6
TA 210

What is happening? I thought I had it last night and then this morning I don't know. I have not added any more chemicals today.
 
weatherillgrp said:
The CYA in the pool is 20. Should I use a stabilizer like trichloroethane to raise it?
Click to expand...
No. The best way is just adding Cyanuric Acid aka CYA aka Stabilizer. Using 1,3,5-Trichloro-1,3,5-triazinane-2,4,6-trione will raise CYA as you chlorinate, but it's also very acidic and you'll end up juggling three or four parameters instead of one.

Have you read
http://www.troublefreepool.com/content/139-recommended-pool-chemicals
http://www.troublefreepool.com/content/142-how-to-chlorinate-your-pool
 
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