Bleach vs calcium hypo smell

[cj133]

Hi all,

I'm not sure if this is the best category for this, but I think it may be.


My CYA is around 30% and I run between 2-3.5PPM FC. My CC is 0.
PH is steady at 7.6 and TA is 120 after a gallon of muriatic acid. My tap water has a very high TA and the pool is around 8500 gallons.
Pool is an above ground steel wall with vinyl liner and I use a solar blanket.

I'm using a Taylor 2006C test kit and I check the water daily, sometimes twice daily.

I've been using Walmart brand unscented 6% bleach in our pool and I have a very sensitive sense of smell and it kind of bothers me. No one else notices it but me. It doesn't smell bad, I just can tell there's bleach. I just asked a friend and he specifically said it didn't smell chlorinish or anything to him, it was great.
Growing up, my dad always used HTH powder in our pool which I believe is just calcium hypochlorite. I don't remember it bothering me like the bleach although it's been 20+ years so who knows. Maybe I've just changed.

There's no other issues that I know of. Everyone else loves the pool, the water is crystal clear and doesn't burn your eyes. I'm using between 8oz and 14oz of bleach in 24 hours depending on the weather I usually add at night after everyone is out so when people are actually swimming the level is closer to 2 ppm.

I'm wondering if I switch to calcium hypochlorite, will the pool water smell different vs bleach or will the results be the same?
What options do I have?

 

[Arizonarob]

Hang tight. @JoyfulNoise

 

[mknauss]

Chlorine is chlorine. Liquid chlorine has a smidge of lye in it for stability.

I suggest you actually are smelling CC. You may not be testing any, but it is there. From the sweat and oil and XXX on your body. Also, you are low in FC, even with a 30ppm CYA. Follow the FC/CYA Levels

 

[cj133]

Chlorine is chlorine. Liquid chlorine has a smidge of lye in it for stability.

I suggest you actually are smelling CC. You may not be testing any, but it is there. From the sweat and oil and XXX on your body. Also, you are low in FC, even with a 30ppm CYA. Follow the FC/CYA Levels

Hi Marty,
I was concerned about the solar blanket having issues with higher chlorine.
If the CC is lower than 0.2ppm, then the breaking point must be lower than 2.0 FC using the 10X rule, no?

 

[mknauss]

TFPC does not subscribe to 'breakpoint'. We use the FC/CYA ratio.

The FC with CYA will have no additional effect on your solar cover.

 

[JoyfulNoise]

The industry “breakpoint chlorination” rule of 10X is mostly incorrect because they use the wrong mass basis for calculations. It’s closer to 5X and even that is mostly unnecessary as UV from the sun combined with proper chlorination will virtually eliminate CCs. Simply uncover your pool for a few hours each day when the sun is on it and that will eliminate any CCs.

Everyone has differing sensitivities to chlorine odor. I smell it in my attached spa when the water is heated and the air jets are running while others say they can’t. Chlorinated water on its own has virtually no smell. What you are sensing is chlorinated water vapors hitting your mucous membranes and then the chlorine reacts with organic compounds on the surface of your nasal cavities producing chloramine odors. Your cover is also likely contributing to your senses because they are dirty and can easily harbor all kinds of biological and organic contamination.

Switching to cal hypo will likely make no difference.

 

[cj133]

The industry “breakpoint chlorination” rule of 10X is mostly incorrect because they use the wrong mass basis for calculations. It’s closer to 5X and even that is mostly unnecessary as UV from the sun combined with proper chlorination will virtually eliminate CCs. Simply uncover your pool for a few hours each day when the sun is on it and that will eliminate any CCs.

Everyone has differing sensitivities to chlorine odor. I smell it in my attached spa when the water is heated and the air jets are running while others say they can’t. Chlorinated water on its own has virtually no smell. What you are sensing is chlorinated water vapors hitting your mucous membranes and then the chlorine reacts with organic compounds on the surface of your nasal cavities producing chloramine odors. Your cover is also likely contributing to your senses because they are dirty and can easily harbor all kinds of biological and organic contamination.

Switching to cal hypo will likely make no difference.

Do you agree with Marty regarding raising my FC level to 4-6ppm due to the 30 ppm CYA?
I thought as long as I was above 2.25ppm I should be fine and occasional drops wouldn't matter. I could be very wrong though.

I'm thinking cleaning solar blankets etc is an entirely different subject but it is something I've wondered about.

 

[JoeSelf]

Minimum FC is 2 for 30 CYA. You need to account for losses. Why do you keep FC so low? You never want to go below 2. The range accounts for daily losses, so you don't go below.

 

[cj133]

Minimum FC is 2 for 30 CYA. You need to account for losses. Why do you keep FC so low? You never want to go below 2. The range accounts for daily losses, so you don't go below.

I would have to claim ignorance on this one.
I thought low was good. I've also been concerned about corrosion with all of the AGPs I see rotting out on here.

 

[mknauss]

Low pH from trichlor tablet/puck use is what accelerates corrosion.

 

[cj133]

As of last night I've increased my FC to 5PPM and I'll keep it above 4 as a minimum and see how it goes.
I'll also make sure the solar blanket is removed for a few hours per day as well.

 

[cfherrman]

FC is safe till 40% cya, so keep it under 12

 

[cj133]

FC is safe till 40% cya, so keep it under 12

At what point does it start to fade a liner?

 

[mknauss]

Well above 40% of CYA level.

 

[cj133]

Well above 40% of CYA level.

Just to see if I understand correctly.
If, in theory my CYA was 100. An FC of 50 PPM would be harmless to the liner? And an FC of 7.5 PPM would be harmless to people, eyes etc?

 

[mknauss]

With a CYA of 100, a FC of 39ppm would be of no issue to people.

We do not recommend maintaining a CYA of 100 nor going to SLAM level FC. But chemically, it would have less active chlorine than 1 ppm FC in a pool with 0 CYA.

Your liner would not fade.

Out of control pH is most damaging to liners. Same with eyes being irritated, except that CC also will irritate your eyes.

 

[cj133]

Ok.. I'm sorry if this comes across really stupid.

But since raising my FC to between 3-5 ppm my bleach usage has gone way up. I've gone from 8oz a day to 24+-. I raise it to 5ppm each night and I'm down to about 3.6 the next evening.

Is this from the sun burning more off or because the pool really needed the higher level and is actually consuming more? Or both?

Temperature is basically the same.

 

[mknauss]

You were not maintaining a high enough FC based on your CYA in the past to keep the pool water sanitary. You are now. Keep the FC above minimum at all times.

 

[Arizonarob]

CJ, just to give you an example, I use 28oz per day in my pool. Sun, swimming, organic debris, etc, all consume chlorine.

 

[cj133]

CJ, just to give you an example, I use 28oz per day in my pool. Sun, swimming, organic debris, etc, all consume chlorine.

What size pool?
I'm betting it's in your signature but my phone doesn't show signatures for some reason.