Completing partial drain

May 13, 2020
17
Phoenix, AZ
I have been a pool owner for 2.5 years and it has been very frustrating. I drained the pool 1.5 years ago and after following everything the pool store told me to do, I now have to partial drain again because CYA is sky high. I finally got fed up at this and have ended up on this forum, excited to go in a new direction. I have read the beginner articles like ABCs of chemistry, Pool 101, and others. I am wondering where to start after this partial drain is complete this afternoon. I am (hopefully) getting a Taylor 2006c of TF-100 test kit this afternoon. I went to 3 stores looking for them and the last store said he could have it delivered to his store this afternoon. If I am not able to get it today, would Leslie's free testing be acceptable for the first week before I can get a kit in the mail?

I will update this afternoon with either my home test or a Leslie's test result after the partial drain and see where to go from there. All my pool info is in my signature!
 

mariane

Bronze Supporter
LifeTime Supporter
May 8, 2012
1,096
Southeast Michigan
Welcome to the forum! You will be so glad you found TFP!
I can address a few questions but the mods will give you even more help.

Stay out of Leslie's for water testing. That is how this mess all started. Your own testing will be more accurate.
Since you've read the beginner articles, you already have more info than all those school kids they hire to do water testing.

Since you've done a partial drain, you don't know how much cya is in the water, but you probably have very little chlorine. Start using liquid chlorine and put the powders and pucks in the back corner of the garage and save them for some other time (when you understand what they add to your pool). Go to the pool math on this forum and plug in all the size information about your pool. . It will let you know how much chlorine to add to keep it at a good level. You won't know for sure until you test your water.
Go to TFTestkits.net and order a TF-100 kit. It is the best bang for your buck and they ship quickly. I don't think you'll have to wait a week.

Liquid chlorine, add ~1-2 quarts per day at 10 % strength if you have it, more or less if it's stronger or weaker, to get you started while waiting for the test kit. The mods might have a change in that number so they will let you know if different.

For test results post:
FC
CC
CYA
pH
TA
CH

Total chlorine is not needed, CYA will be very important.

You'll be glad to see the TFP sparkly water that you've never seen while going to the pool store.
Welcome again!
 
Last edited:
May 13, 2020
17
Phoenix, AZ
Thanks for the reply. Yes, I am done going to Leslie's for good. I just meant to test my CYA post drain, since it was only a partial drain, until my kit arrives in a few days. But I figured a Leslie's CYA level would be decent enough for a few days while I have to add chlorine back in instead of just guessing/hoping it is low enough. I have the pump rented, I may as well do another quick partial drain if my CYA is still high. Then I can test manually next week.
 

Mdragger88

Bronze Supporter
Jun 1, 2018
1,353
Hernando, Ms
I wouldn’t add / remove anything based on a Leslies test. They are known to be all over the place. Also not sure what sky high is but in general if u want 50% less cya you need to replace 50% of your h2o & so on.
 
May 13, 2020
17
Phoenix, AZ
Okay good to know. Well the last Leslie's test said the CYA was 180, so I removed roughly 60% of my water, but didn't want to drain too much at once and leave it exposed to sun. So I am thinking I may be close to 70 CYA after the refill is complete. So I guess something around 70 would be manageable for a few days before my good test kit comes and I can adjust/partial drain again after that? At 180 I was not holding any chlorine and had to do this to break the cycle. Even a CYA of 80 is not ideal but at least I would be able to maintain chlorine better before I get a better test.
 
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mariane

Bronze Supporter
LifeTime Supporter
May 8, 2012
1,096
Southeast Michigan
By "not holding chlorine" do you mean the FC keeps dropping? If so that is because your CYA is so high, you need a massive amount of chlorine to kill any organics in the pool. For ex. if you need (just a guess number) 30 FC to maintain clear non algae water, you would have to add 3 gallons of 12% chlorine DAILY to maintain your FC level of 30. So if you're loosing chlorine, its because the organics are using it up faster than you can put it in. It will result in a green pool quickly. So its very important to get the CYA level down to where your chlorine usage is manageable.
 
May 13, 2020
17
Phoenix, AZ
Yes I ordered the TF-100 kit today.

My current predicament is that yes my CYA was so high yesterday I simply could not add enough chlorine to get my FC above 1. The pool was starting to get a very slight amount of algae around steps. I knew it was teetering on the edge. So I decided to do a partial drain last night. I have just completed filling the pool now but all pool stores are closed and I do not have a home test kit because I just ordered it. I didn't feel I could wait to do the drain until the kit showed up because it was already turning on me. So I plan to shock it tonight with 10% chlorine using pool math assuming my FC is 0. The only problem is I am flying blind as far as current CYA, alkalinity, PH, etc. In my mind my best option now is to shock tonight and get a test at Leslie's in the AM to see new levels. Even if it is inaccurate, it is something other than a total guess. My best guess is my CYA is in the 50-70 ballpark given it was 180 before the partial drain and I was able to drain roughly 70% of the pool.I will then do my best until my home kit comes and adjust from there. Does this sound reasonable?

Pool currently is pretty clear and blue other than the small patches of algae beginning in corners and all numbers were testing in range other than a low FC and high CYA via Leslie's testing before the partial drain today.
 

Flying Tivo

Well-known member
Jan 24, 2017
1,895
Monterrey, NL, Mexico
You are in AZ and your fill water has high CH. Since you already have algae you will most likely need a slam. I would wait until the new test kit arrives and test. You will find out you will probably need another drain refill, so no need to waste on chlorine just now. Just add half a gallon of liquid chlorine 12% per day so it does not get worse.