Bleach Usage

[brownchristian]

I am trying to get an understanding on how much bleach I will be using on a regular basis. I have been treating the pool with bleach for four days now. Daily I have had to add between 100 - 130 oz of bleach to maintain an FC of 10 due to a CYA of over 100. So here are my questions.

1. I assume that I will be able to determine an amount of bleach that I typically add daily to maintain my FC in the proper range. Basically after a week or two if I am typically adding 120 oz daily I should be able to learn that without testing daily I can just add 120 oz and be done.

2. I think I understand that with a CYA over 100 it uses the bleach faster than if the CYA was lower in the desired levels. So does this mean with an FC of 10 and a CYA over 100 I will be using substantially more bleach then I would be if the CYA was lower and therefore being able to lower the FC?

3. If my understanding of question 2 is correct how much bleach can I expect to use once I get my water to the desired CYA?


I guess my main reasoning for these questions is because in my initial thoughts I didn't realize I would be adding over a gallon of bleach daily. If I bought bleach weekly I would have to keep on hand a minimum of 7 gallons of bleach which could be a pain to store. How much do you guys typically have at any one time?

I hope all of this makes sense. Woke up in the middle of the night pondering these things and wanted to get them written down so I didn't forget.

 

[supertune]

I'm too new to be able to tell you about your chlorine consumption.
Do you have a place to buy liquid chlorine (10-12.5%) from a pool supply?
I'm lucky to have a pool supply 6 blocks away and get 12.5 % liquid chlorine, 2.5 gal. carboy for under $5.
The jug deposit was only $4.
My small 4200 gallon pool at a CYA of 40 uses between 16-18 oz per day with 12.5% liquid chlorine in 70% direct sun, no rain.
With our afternoon rains I go up to 20-22 oz.
I have never had to shock again and my pool #'s are always good except and little acid to keep the PH in check and 2 oz polyquat about every 10-12-days from being half under the neighbors trees over into my yard.

However... I did get Sparklypoolitis from this site!

Chuck

 

[Siamese]

I've used the BBB method for a few years and after the pool is fully balanced, you'll have a general idea of how much your pool "eats up" on a daily basis. However, this amount will vary based on the bather load, the amount of sun, and how much stuff (leaves, algae, etc.) fall into the pool. That's why you must test the pool for the free chlorine level EVERY day and add the amount of bleach/liquid chlorine to bring the FC up to the target level for your corresponding level of CYA. The poolcalculator.com site is great for identifying the precise amount needed.

Having a high level of CYA like you do, doesn't use up more chlorine per day, in fact it will better protect the chlorine in the pool from being destroyed by the sunlight than a low CYA level will. However two bad things happen when you have a high CYA level: 1) Your target FC level is going to be a high number, much higher than you can test with a standard drop based kit and 2) if you ever get an algae bloom, your shock level (the amount of FC you'll need to get to and hold) is going to be astronomical.

It would be helpful if you could post a full set of test results . If you don't have a good test kit, I'd recommend getting one right away -- www.tftestkits.net sells the kit that most of us use. Based on the results, we can give you further advice, but know that it's likely that one of the first steps might be to drain a portion of the pool to lower the CYA level.

 

[Richard320]

I've used the BBB method for a few years and after the pool is fully balanced, you'll have a general idea of how much your pool "eats up" on a daily basis. However, this amount will vary based on the bather load, the amount of sun, and how much stuff (leaves, algae, etc.) fall into the pool. That's why you must test the pool for the free chlorine level EVERY day and add the amount of bleach/liquid chlorine to bring the FC up to the target level for your corresponding level of CYA. The poolcalculator.com site is great for identifying the precise amount needed.

Having a high level of CYA like you do, doesn't use up more chlorine per day, in fact it will better protect the chlorine in the pool from being destroyed by the sunlight than a low CYA level will. However two bad things happen when you have a high CYA level: 1) Your target FC level is going to be a high number, much higher than you can test with a standard drop based kit and 2) if you ever get an algae bloom, your shock level (the amount of FC you'll need to get to and hold) is going to be astronomical.

It would be helpful if you could post a full set of test results . If you don't have a good test kit, I'd recommend getting one right away -- http://www.tftestkits.net sells the kit that most of us use. Based on the results, we can give you further advice, but know that it's likely that one of the first steps might be to drain a portion of the pool to lower the CYA level.

Yep!

The tester can only read to 100 - it might be 150. In which case you have been skimping on chlorine, algae is starting to get a foothold, using up all your bleach. Try diluting the sample 50/50 with tap water then test CYA and double it. Does it still come out close to 100? Or is it higher?

What is the CC?

Even accounting for temperature, that's a lot of bleach. Something's going on. A full set of test numbers would help.

 

[woodyp]

I suggest you start a log of your tests results and what you add so you have some reasonable idea of what to expect over time and varying conditions. Wish I could give you a hard answer.......but every pool here is different. My pool is call it 12,500 gallons and I use a 96 oz. jug per day on "average". Bather load, rain, heat, all change that. We all work off of "averages" and "ranges" to start with. Your mileage may vary as they say!

 

[brownchristian]

Here are my test results from Sunday. I have not done a complete test since then. I have since maintained the FC around 10 and lowered the PH.

FC - 5.5 (There have been tabs in the chlorinator and I have been adding bleach so I assume that is why this is high)
CC - 0 (Not sure how accurate this is. When I added the drops it clouded the water but didn't change the color. Is it common for this to be zero?)
TC - 5.5
PH - 8.2 (After the test I added 3/4 gallon of acid and after 2 hours I retested and PH was 7.2)
T/A - 260
CH - 400 (This test is VERY inaccurate. I got tired of counting after 30 and just started releasing drops til the color changed.)
CYA - 100+ (Again I am not sure how accurate I was with this test. Pretty sure the black dot disappeared before I stopped pouring but when I stopped the water was right on 100.)

 

[aa62579]

I thought that amount of bleach was high at first, but really, I guess that is just enough to raise chlorine by 2.5 - 3.5 each time for a pool your size. Seems like a lot of pools on here lose 1 - 3 per day, and those with a high CYA use slightly more than those with a lower CYA.

I have a light bather load, but full sun, and have averaged 1.5 loss per day with 0 CC and a CYA of 55.

So, even after you get your CYA down, you still might expect to lose 1-3ppm per day and need to add 38 - 115 oz of 6% per day.

Use a good test kit and determine you CC and if you are losing chlorine overnight. You might need to shock. If not, 3ppm per day might be the amount of chlorine you can expect to lose each day and you could probably get by with adding the same amount each day and occasionally skipping the test.

 

[anonapersona]

Several things... if you are going to test, you really do want to be patient and count it all, particularly for the CYA test since that one uses a lot of reagent.

Remove those tabs from the inline chlorinator right now. It is not easy, put on a rubber glove and get some small sticks to help.
You seem to be requiring a bit too much bleach, I suspect you may need to shock. An overnight test will tell you if that is so.

Before you do, be sure that the pool is as clean as possible. In my pool the waterfall collects sand (rocks are decaying) and algae starts there, all is better when I keep that clean. You may need to scrub the pool water line or corners of the steps or something, check around to see if you have some spots that need attention. Give the pool a good brushing all over, all the nooks and crannies and while you do this keep the FC at the upper end of the range. That may be enough to clean it up, or not. At that point, do an overnight chlorine loss test (very carefully) and report back to the forum.

Personally, I too find it hard to test and dose every day although I keep promising myself I will do that. So I keep to the every other day plan where I add 4 to 5 ppm above the min FC, expecting the hit the min on the second day. But I got to that point AFTER I got the pool in top shape and learned exactly what it required. And when I mess up I pay the price in extra attention. I will admit that my records show that in the winter I sometimes go a few weeks without working on the pool. But I do notice if it gets dull and I jump to it then and have to play catchup.

So, for now, I suggest that you be obsessive about testing and dosing daily. Give it a few weeks of daily attention. Make a chart that records what you tested, date and time, and what you added and what your goal was for each addition. That sort of record will show you exactly what is going on. Then you can see how the pool changes as water temps go from 65 to 85 to 90+ and what rain and falling leaves do to the chemistry.