Thinking of switching to Bleach as Chlorine...

[Cbed1013]

I am thinking of making the switch from Chlorine Tabs/Shock to liquid bleach chlorine. From what I have read on this site and others, the bleach is one of the simplest ways to chlorine the pool w/o adding extra chemicals which can cause adverse effects.

My first question is since I live in Phoenix, AZ and the temps are very high in the summer, would the liquid bleach stand up to the high temps or be relatively ineffective because of the sun eating away at it?

Additionally, approximately how much 6% liquid bleach would it take to maintain a proper chlorine range? My pool is approximately 25k gallons. I know that this is going to be a pure estimation because each pool is completely different. I am just trying to get in the ball park to see how much bleach I need to have on hand to ensure I can keep my chlorine levels in the proper range.

Thanks!

 

[duraleigh]

Chlorine is chlorine. The chlorine in bleach is no different that the chlorine in the tabs.

You would likely use somewhere around 1 gallon daily.

Read "The ABC's of Pool Water Chemistry" up in Pool School to get a better understanding of the FC/CYA relationship

 

[Cbed1013]

I got a test kit and have tested my water. The big thing that is standing out to me is that my CYA is off the charts...100+. Now from reading the Pool School I have found out that the only way to lower the CYA is to drain and fill...However, being in Phoenix and having a plaster pool, I can't drain in the summer due to the risk of cracking my plaster.

According to the CYA/FC chart I found on the website, with a CYA level of 100, the minimum amount of Chlorine I need at all times is 7 ppm (with a target of 12 ppm). I have 2 questions:

1) Is there anything else I could do in order to help w/ the CYA w/o draining? Maybe a temporary solution until I can drain. Also, what temp is safe to drain w/ a plaster pool w/o risk of cracking?

2) Am I interpreting the CYA/FC chart correctly? Do I need to maintain a FC level of at least 7 ppm to keep the water sanitary?

Thanks for all the help!

 

[Bama Rambler]

Draining is about the only effective way to lower the CYA. Since you're in Phoenix you may have reverse osmosis available to you, but it's pretty expensive, and unless you're on severe water restrictions, it's probably better just draining and refilling. You can do the drain and refill a little at the time. It just takes a little longer and uses a little more water than an "all at once" drain/refill.

Have you ran the CYA test using half pool water and half tap water and doubling the result to get a better idea exactly how high the CYA really is. It could be much higher than 100.

You are reading the chlorine/CYA chart correctly. If the CYA is just 100, you can never let the FC get below 7 ppm.

 

[Cbed1013]

I will try your idea of testing half pool water and half tap water then doubling it tonight and report back. In the meantime, in terms of chlorine to use, I am guessing liquid chlorine/bleach would be my best bet, because the powder shock and tabs would continue to raise the CYA, right? I may have to bite the bullet and slowly drain and re-fill the pool a little at a time. Otherwise, Ill be spending tons of money on chlorine trying to keep it up around 7-12 ppm.

 

[Bama Rambler]

Liquid is the best. I'd add enough to get to about 10 ppm FC and keep it there for the time being.

 

[Cbed1013]

the test kit I have only has a max reading of 5 ppm for chlorine. Can I utilize the same method you mentioned about testing the CYA with half tap water and half pool water then doubling it for Chlorine as well?

 

[Bama Rambler]

I'm sorry. When I read "I got a test kit and have tested my water". I assumed that you had one of the recommended kits.
Which kit do you have?

You'll need the FAS-DPD chlorine test to test at the levels you need to maintain. I suggest you go ahead and order the TF-100 from Pool supply world and get the SpeedStir option too. That will make your life a lot easier.

You can't do the FC test like the CYA test as the tests don't work the same and most tap water has chlorine in it so it in itself would throw the reading off.

 

[chiefwej]

It's just as sunny and almost as hot here in Tucson. I just did a full drain and refill on my pool. Starting early am, I drained through the day and by that evening had the pool empty then using three hoses had the pool back over 1/2 full by the time sun was on it the next am. You can use a hose or even a garden sprinkler to spray down the surface to keep it from over heating in direct sun. It just takes a little planning and some of your time and attention.

BTW: I was going to do RO treatment, contacted local company (quote $375). Just to avoid wasting water here in the desert, I OKed it. They scheduled it over a month out, then called a day or two before saying they had to reschedule due to their equipment breakdown. Didn't know when, they would call. I cancelled, did a full drain and refill <$100 for water.

 

[Cbed1013]

Alright...so I just got my TF-100 Test Kit in the mail. I have performed my first test and the readings are below.

FC: 7 ppm
CC: .5
TC: 7.5
TA: 110
CYA: 150
PH: 7.2

Now according to the CYA/FC chart, with a CYA of 100, I would need a minimum of 7 ppm chlorine. However, it does not go up to 150 on the CYA. What do you think I should keep my FC at to maintain it at a proper level? Once I know that, I can utilize the pool calculator to figure out how much liquid chlorine to add. Secondly, the Pool Calculator is asking for a target TA level. The Pool School states TA between 60 and 120 is acceptable, so I guess I am good there. Finally, the PH being 7.2 is on the low end of the range, so I think I would like to raise it up to around 7.5. My question is, the Pool Calculator mentions "Washing Soda" can anyone explain what that is? I have seen soda ash at the pool store, but never heard of washing soda. Any idea on where I may be able to pick some up?

 

[duraleigh]

I think I would leave your pH right where it is. It'll tend to rise naturally on it's own and even at 7.2, it's very acceptable.

If you decide to raise it anyway, I suggest using 20 Mule Team Borax. fewer side effects than washing soda and more easily obtained....(grocery store)

Before I comment on your CYA and FC relationship, did you test CH? What was/is it?

 

[Donldson]

Soda ash and washing soda are the same thing. Since your TA is good you would be better off using borax as it will affect your pH while barely touching your TA. Soda ash raises both. Also at 7.2 you are fine, it will likely rise on it's own.

How did you get your CYA level? If the dot disappeared before it reached 100 and you are guesstimating, you cannot do that. Because of the way the test works it cannot measure about 100 CYA. If that is the way you did it you need to retest and instead of straight pool water you mix 50% pool water with 50% tap water and use that to rerun the test. Whatever number you get with that, double it and that is your CYA.

The reason the chart only goes to 100 is because it is very difficult or impossible to properly maintain a pool with that high of CYA. For an example of why it gets unreasonable, if you really have 150 CYA you would need to maintain about 10-17 FC at all times. Shock level would be about 60 FC.

 

[Cbed1013]

I just tested my CH...coming in around 900. Question regarding the test. Am I supposed to stir the vial after I add each drop of the R-0012? When I did the test, I added 10 drops at a time and then stirred. The red liquid clearly turned to blue at 90 drops...

In terms of the CYA...I did use half pool water and half tap water. It was a reading of 75, so when doubled the CYA is 150. I understand the CYA is very high and I am going to have to maintain very high FC levels, but being in AZ in the summer the only way to replace water would be to drain and add slowly to avoid plaster damage from the heat. Also, I have plaster issues I need repaired while the pool is empty so I am going to hold off until it is cool enough to drain, have the plaster repaired and then fill with fresh water. In the meantime, I'm going to be using a LOT of liquid chlorine!

 

[Donldson]

Sorry to assume you did the CYA test wrong, a lot of people try to guess it. you are ahead of the curve!

I was going to say, being in Arizona, reverse osmosis is an option for you to reduce both CYA and CH. However, if you are in need of some plaster work and will have to drain your water anyway, I suppose waiting a few months will be doable. Please keep in mind that with an FC above 10 you will not be able to test pH correctly so you will need to let your FC drop down occasionally to test and adjust your pH.

 

[linen]

I just tested my CH...coming in around 900. Question regarding the test. Am I supposed to stir the vial after I add each drop of the R-0012? When I did the test, I added 10 drops at a time and then stirred. The red liquid clearly turned to blue at 90 drops...

The CH test is a tough one, a speedstir really helps, but I think your method is okay to get a rough estimation of CH...and your CH is obviously very high.

Is water expensive for you? You could do small drain refills daily...it will waste a lot water though. Another approach is to pump water out form main drain while filling water at the other end of the pool...though this still wastes a lot of water though maybe less.

What does your water look like? If it is crystal clear, then you could just maintain a higher FC level. You can use the poolcalculator.com to give you suggested FC levels up at 150 ppm cya. It gives me 11-13 ppm for the normal FC range.

 

[Cbed1013]

My water is clear. But, I have been fighting green/yellow alge growing on the sides every couple of weeks (but now I know that is most likely due to not having enough FC in the water).

I will probably stock on on liquid chlorine and keep the FC between 11-13 for the next couple of months before I can do a complete drain. Will swimming in water with FC that high cause negative side effects (i.e. very dry skin, odor, etc)??

Thanks for everyone's help!!

 

[duraleigh]

With your CH too high and your CYA too high as well, I would drain/refill at least 50%.

In the hot AZ sun, you can do so and never change your water level. Siphon off the top at one end and then refill from the bottom at the other end. Match the flow of your refill water to the outflow of your siphon and the water level will not vary.

The cold refill water will also tend to stay at the bottom of your pool allowing you to drain CYA from the top, warmer water.

Test the CH of your fill water as well so you'll know how much improvement you will have.

Do you have a whole house water softener?

 

[linen]

Is the algae mainly growing on the sides that are shaded?

I agree with duraleigh, if it is mustard algae, you would need to keep FC at 15% of the cya level which in your case is 22.5 ppm FC just to keep it at bay

 

[Cbed1013]

I know it grows in certain areas, but not only the areas that are mostly in the shade. Usually on the vertical areas of the steps and the bench seat within the pool. I am going to start raising up the FC level and see how quickly it diminishes to see what I would be up against to keep the FC somewhere in the 11-13 range. If I still see the alge growing with FC that high, I may have to utilize Dave's suggestion of siphoning it off slowing and replacing with fresh water.

Thanks again for all the suggestions!

 

[Bloomfield]

Is the algae mainly growing on the sides that are shaded?

I agree with duraleigh, if it is mustard algae, you would need to keep FC at 15% of the cya level which in your case is 22.5 ppm FC just to keep it at bay

What kind of algae grows mainly in the shade? I had that once in my pool.