How Much Bleach = How Much Dichlor?

[trendle]

Hello, I have been doing a lot of reading about water quality and the dichlor/bleach method. I have had issues with cloudy water (ph and TH are OK) and wonder if it isn't the CYA levels causing it. Rather than keep using dichlor granules I would like to switch to bleach now rather than wait for water change time (winter is a bad time to change water).

Is there a simple equation for how much 6% bleach is equal to how much dichlor? I have read a lot of articles and some seem to skirt around a 1:10 ratio for dichlor to 6% bleach but never any "concrete" answer. Is this the case?

If so, 1 oz dichlor = 10 oz 6% bleach, 1/2 oz dichlor (1 tbsp) = 5 oz 6% bleach, and so on...

Just wanting to make sure I am getting this right before I make the switch. I currently use Nature2 and dichlor for "shocking" as my wife seems to be sensitive to MPS and only use MPS when we have heavy use.

[chem geek]

The rough rule-of-thumb for how much oxidizer you need to handle bather waste when there is no ozonator is that every person-hour in a hot (104ºF) tub requires around 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of non-chlorine shock (43% MPS). 1 teaspoon of Dichlor is roughly equivalent to 1-1/2 fluid ounces of 6% bleach; 1 tablespoons of Dichlor is around 4 fluid ounces of 6% bleach; 1 ounce of Dichlor is around 8-1/2 fluid ounces of 6% bleach.

Don't forget to lower your TA level to around 50 ppm and to add 50 ppm Borates since that will be needed for pH stability since Dichlor is net acidic when accounting for chlorine usage/consumption while bleach is not.

[trendle]

Thanks for the quick reply!

[trendle]

One more question... The rates you suggested are much more than what the product directions state. For example my MPS says 1 tbsp per person after soaking and doesn't indicate that it changes based on length of soak. Your suggestion is 2 1/3 tbsp per person-hour (2 people for 1 hour = 4 to 5 tbps). For the dichlor my directions state to superchlorinate with 1 tbsp and your suggestion would be to dose at least 2 tbsp.

For reference my tub is rated at 380 gal so probably has 350 gal in it during normal operation. Also we almost never go over 102 degrees and usually are at 100 so we are a little cooler than the worst case scenario.

Could my cloudy water issue be because I have not been using enough of the product (MPS or dichlor)?

[chem geek]

If you have an ozonator, you can use less, perhaps half as much or maybe even less. However, without an ozonator, the amounts I gave are roughly correct for most people. And yes, you are probably not using enough oxidizer to get rid of your bather waste and cloudy water can be a result. Note that non-chlorine shock (MPS) doesn't oxidize everything to prevent cloudy water so you usually need to shock with chlorine every week or so if you are using MPS regularly, say in a Nature² system. You'll know if you are using enough oxidizer/sanitizer if you are able to measure a reasonable minimum residual (1-2 ppm FC) before your next soak. If you get to near zero for an extended period of time (say, 8 hours or more), then your water can go south in a hurry and significant biofilms can form.

[trendle]

Thanks again!