help understanding cya and shock

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SJ1193#

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May 6, 2017
30
Baton Rouge, Louisiana
I am helping my parent's balance their pool. It has been green most of summer even though they supposedly have a pool guy that comes every other week.
19x38 3'shallow, gradual slope to 9ft sand filter, currently using hypo/cal bags of shock and tablets.
ph 7.5
alk 120
cya 90
I live 30 min away and don't have readings for chlorine right now. 4 days ago I put in 3 bags of their shock. The next day, I poured in 6 gallons of liquid 10% chlorine and 2 bags of their shock. I was just guessing. when I got home and looked at pool calculator it said with 90 cya their shock level would be 30. Is that correct. I will go their today and get fc level. I never did cc level because it was evident at time that there was algae.
Let me know if I am on the right track. Also, they are older and will not be able to check water everyday, so I will have to do some powdered shock. I can check pool balance once a week.
Thanks for your suggestions.
Also, wondering if I should drain and lower that cya level?
 
Hmmmm...that's such a dilemma. Once every two weeks for the pool guy isn't enough obviously, yet they're not really up for frequent testing.

SLAM Process
FC/CYA Levels

First off everyone needs to stop using any granular or sold forms of chlorine. They're just compounding the problem. Liquid chlorine all the way from now on.

I would suggest a salt water chlorine generator be placed after you SLAM the pool. A SWG would provide daily chlorine and less daily care by them. If you are testing with the right tester and can trust those results, I mean? That way their high CYA could work to their benefit BUT the SLAM would require a MESS more liquid chlorine to clear the green.

Otherwise yes, drain half and retest. Then do a SLAM process with the lower CYA level. Then figure out how to have the folks add x amount of liquid chlorine daily/every other day and do as much testing/tweaking as possible.

I feel for ya...trying to fix a chlorine pool and you yourself manage your Bacqua pool <cough cough> ;) Your parents are blessed to have your help. Holler back with questions.....

Maddie :flower:
 
Hi SJ,
the SLAM level for FC is about 40% of whatever the CYA is. So with CYA of 90, the SLAM FC is actually 36.

FYI if the powder shock you are adding is trichlor, then every time you put some in, its also increasing the CYA. The same goes with the pucks.

The reason we dont recommend slamming with high CYA, is because it takes a LOT of bleach to get to those high FC levels. It also takes a lot of test regent to test chlorine that high too. TFP is not only about how to take care of our pools chemistry wise, but economically.

If you can bear it, it would be best to drain at least half of the water and refill. That would get your CYA down to a more manageable level. Less chlorine, less test regents, less $$.

You are going to have to do it soon any way if you want to be able to economically manage the pool long term.

Back to the slam part of my reply to you.
the M in slaM means to Maintain The FC Level. That means testing and adding chlorine every single day to get the FC back up to SLAM level. If someone cannot do that, then its going to be very tough to get rid of the algae. A pool full of algae will take the FC from 36 to zero in very short period of time.......
 
First let me say, thank you for all your advice. Also, this will definitely be a nonconventional trouble free pool because (without going into too much detail here) there is no physical way my parents can pour chlorine every day in pool and it is not the time to change system. I definitely understand that it will be a challenge but hope your advice can help me conquer it to some degree.
19x38 3'shallow, gradual slope to 9ft sand filter, currently using tablets.
So, this was the readings when I checked pool 3 days ago. Pool is crystal clear, but needs to be vacuumed. I have a couple of questions.
ph 7.5
alk 120
cya 60
cc .5
fc 14
1. Pool Guy will not come until Friday to vacuum. In meantime should I brush and stir up junk on bottom to go to filter or just let it sit.
2. I should be there once a week and pool guy bi weekly. I have the tablets in dispenser going in pool constantly.
 
oops posted too soon
2. what do you suggest I do when I test water weekly (bring to swim level or shock level?)
3. what do you suggest I have pool guy do. He only uses the dip strips and I think he's been throwing a couple bags of shock in. I come to realize he does not understand pool chemistry, but I want to keep him for brushing and vacuuming if necessary. (I have a lot on my plate and trying to have a"trouble free pool" from a distance LOL!
 
SJ1193# said:
First let me say, thank you for all your advice. Also, this will definitely be a nonconventional trouble free pool because (without going into too much detail here) there is no physical way my parents can pour chlorine every day in pool and it is not the time to change system. I definitely understand that it will be a challenge but hope your advice can help me conquer it to some degree.
Click to expand...

As Maddie suggested above, you need to consider converting the pool to a salt water pool.
 

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Sorry if it is confusing. This is a chlorine pool. (I am using bacquacil in my own pool, this is my paren'ts pool). I am trying to get my parents pool situated, because due to some events, they have been unable to keep it clear this summer. As I stated previously, it is not a situation where I can change system. I have done TFP in my own pool, but just like a diet or exercise program, sometimes I deviate. I like a change now and then...But, that doesn't mean I don't like TFP.
the facts in my parents' pool remain the same, and will.
there is no physical way my parents can pour chlorine every day in pool and it is not the time for them to change a system. I definitely understand that it will be a challenge but hope your advice can help me conquer it to some degree.
I know tablets add CYA, I understand. But I am only here one time a week. I cannot change any of the situation. I understand if you don't have a clue how to help my specific situation, but please don't tell me to convert or just use chlorine... I wish I could. Someone must understand the difficulties of helping elderly parents and know that sometimes you have to make due. If you don't know, just say you don't know. Don't judge.
I am asking, if I have the tablets during the week, should I add liquid chlorine up to shock level once a week when I am here or just use tablets.
And should I brush bottom of pool or wait till pool guy can vacuum in 4 days.
I respect your TFP process, understand it and like it. But, am unable to use it at this pool
19x38 3'shallow, gradual slope to 9ft sand filter, currently using tablets.
Pool is crystal clear
ph 7.5
alk 160
cya 70
cc .5
FC 11
Is there another pool forum you would suggest if I need help with the tablet aspect, as I know it is not your thing, but I also am trying to figure out if I can use less tablets as to not raise CYA so high. Thanks
 
Can they add cal hypo?

Then when you check the pool each week, drain sufficient water to get CH and or CYA back in line.
 
For every 3 ppm of FC you are adding with trichlor you are adding 2 ppm of CYA.

If you plan on using trichlor you need to plan on a 50% drain or doing a Water_Exchange about every month.

The higher you let the CYA go the more pucks you will need to use to keep the correct FC/CYA ration. See FC/CYA Levels

The more you or the pool guy brush and vacuum the pool the healthier it will be. You cant brush a pool too much.
 
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I would change to a different pool service which will do what you want, and have them come weekly instead of biweekly. If you go weekly and the pool service comes weekly, meaning the pool gets 2 visits each week, you can keep the pool in shape.
 
Cal Hypo is Calcium Hypochlorite. They add calcium and chlorine to your pool water. No CYA.
 
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