Hi, I'm new to TFP and I have a question. My CYA is 0 and my FC was 0 even after putting a whole jug of bleach in the pool. I have since shocked the pool and FC is now at 5 and CYA still 0. I have added CYA to pool in a sock resting in skimmer basket. Is it safe to swim in?
CYA & FC
- Thread starter Debs Pool
- Start date
- May 3, 2014
- 63,067
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Welcome to the forum!
Chlorine in a pool with 0 CYA has a half life of less than an hour. So you do need CYA of between 30-50 ppm to protect the chlorine. How much have you added? How are you testing your water chemistry?
I would say the pool is safe to swim in. But it is preferred that it is holding at least a minimum FC based on FC/CYA Levels prior to swimming.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
Chlorine in a pool with 0 CYA has a half life of less than an hour. So you do need CYA of between 30-50 ppm to protect the chlorine. How much have you added? How are you testing your water chemistry?
I would say the pool is safe to swim in. But it is preferred that it is holding at least a minimum FC based on FC/CYA Levels prior to swimming.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
Hi thanks for your help. I added 27 oz as instructed by the pool math app. FC was high around 10 this morning...shocked last night. Now it's about 5 or 1 below highest level according to Accucheck test strip. CYA I just added now and put in sock in skimmer basket.
- May 3, 2014
- 63,067
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Please fill out your signature. Without a pool volume, etc, we cannot help you out if you want us to check your chemical add volumes.
Also, you need a proper test kit. See Test Kits Compared. I suggest the TF-100
Also, you need a proper test kit. See Test Kits Compared. I suggest the TF-100
Thank you for the signature suggestion. Didn't even know it was there, lol. So do you think it was ok for me to put the CYA in sock and rest it in skimmer basket?
- May 3, 2014
- 63,067
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
That is a great method to add CYA. You are targeting 40 ppm. Good plan.
Be sure to order your test kit now.
Be sure to order your test kit now.
Hi again. So I have gotten my CYA level up and now my pool is green. PH is 7.2, FC is 5 (after putting 2 gallons of bleach in pool last night), ALK is 100 and my CYA is 60 - 70. Please help 
- Mar 24, 2014
- 2,455
- Pool Size
- 32000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool SJ-55
SLAM - Shock Level and Maintain - Trouble Free Pool will clear your algae although with your small pool a drain/refill might be quicker.
It's important to keep your FC above the minimum in this chart at all times. Chlorine is consumed during the day so it needs to be replenished just about every day.
It's important to keep your FC above the minimum in this chart at all times. Chlorine is consumed during the day so it needs to be replenished just about every day.
Thanks for your reply Mr Bruce. So according to the chart my minimum sb FC of 5 and that's what it was this morning after adding 2 gallons of bleach last night. I guess I can add more tonight since I shouldn't do it during the day, correct? It also needs to be much much higher for the SLAM, right? How much bleach should I add? I use bleach with 6% chlorine in 121 oz jug.
- Mar 24, 2014
- 2,455
- Pool Size
- 32000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool SJ-55
You can add chlorine (bleach) to your pool anytime. In fact, if you read the SLAM article you should be doing it several times a day during the SLAM. Use the pool calculator to determine how much chlorine will raise you to SLAM levels and then how much to add as you are maintaining that FC level.
I was under the impression that if I add bleach during the day it will just burn off. But I did read that during SLAM you have to keep adding so I was a little confused...lol. Also my PH seemed to drop a bit overnight? is that normal during slam
- Mar 24, 2014
- 2,455
- Pool Size
- 32000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool SJ-55
7.2 is perfect pH to start a SLAM. After you start though, the pH test will be unreliable with a FC over 10.
Some of the chlorine will burn off during the day, but some will work on the algae too. You need to raise FC to SLAM level (toggle the slider in the app) and maintain that level as often/much as possible. Some are able to test and add chlorine every 1 hour, which can speed up the process, but if you can't do it that often do it as often as you can. 3x a day is about the minimum though.
What test kit are you using?
What test kit are you using?
Hi, as of right now all I have are the Accucheck Dipsticks. I know I need to get the TF test kit but I don't have the $ right now. I'm doing the best I can with these dipsticks...lol
- Jun 8, 2019
- 4,581
- Pool Size
- 20000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
The dip sticks won't be able to help you. You have to have a reading on FC more than "somewhere between 5 and 10ppm" or "above 10ppm".
In a well managed pool that has always had adequate free chlorine, adding bleach at night is the most efficient use of liquid chlorine. But I think that bit of advice has been turned into “never add bleach at night” in some pool maintenance circles. Following TFP methods, you add bleach when it’s needed. And if your FC levels have dropped to 0 or dropped below recommended levels for your CYA......it is needed. Algae can reproduce really freakin fast in low chlorine/ warm water/daylight conditions.
Thanks for your words of wisdom. I am going to look at adding chlorine differently from now on.