Dichlor Readings?

[drober30]

A level of 3-5 parts per million of Dichlor is needed at all times?

It seems every time I check my tub with a test strip that the chlorine does not register.

I add after every use which is every night.  About 1 1/2 tsp

So if I add Dichlor at night should I have the 3-5ppm reading before entering the tub the next night?

I'm wondering if I need to add more Dichlore at night when I get out so I get a good reading the next day?

[bulmer4nc]

We add dichlor after each use in the evening.  We add enough to get it to around 3-5ppm like you say and then by morning it's around .5-1.   By the time we use it the next evening it reads 0 if I test.   Best part of this type of method is that there's no chlorine smell when you use the tub.  You're adding the sanitizer after you leave to kill anything that was introduced.  The only time that there's still chlorine in the water is if I had shocked the night before.  We use about 3tbsp of Dichlor to superchlorinate as a shock and it's usually in the 3-5 range by the next evening.

[Bill_Stevenson]

Dichlor does not live long at the high temperatures found in a hottub.  The 3-5 ppm reading should be about 10 minutes after you treat the water.  Within hours the amount of free chlorine would be well below that level.  

The smell that most people associate with dichlor is actually caused by chloramine, also called combined chlorine.  By shocking once per week this stuff is burned off.

From your post, it sounds like all is well with your tub.

Regards,

Bill

[drober30]

Thanks!

Sounds like I was doing it right.

Except when I was shocking I was using 3tsp. Sounds like I should switch to 3 TBSP

[Vinny]

The amount to shock with is 7 to 10 times the combined chlorine amount. This amount is different for all tubs. If you tub takes 1 teaspoon to get to 2 PPM then you may be able to get a shock value from 3 teaspoons (which is 1 tablespoon).

If you have a Taylor kit, it measures free chlorine FC and total chlorine TC, the difference is combined chlorine CC.

So if CC value is 0.5 PPM: 7x is 3.5 PPM and 10 x is 5PPM, if 3 teaspoons give you 6 PPM then you would have done the shock. But if the CC was at 1 the 3 teaspoons wouldn't be. Or you can use MPS to shock and the calculations go away(I haven't used MPS yet myself)

Hope this helps.

[Soakin]

It seems every time I check my tub with a test strip that the chlorine does not register...I add after every use which is every night.  About 1 1/2 tsp...
I'm wondering if I need to add more Dichlore at night when I get out so I get a good reading the next day?

Don't get hung up on tsp/tbs formulas.  Situations differ based on size of tub, number of users, water chemistry and the like.  I'm a little more conservative about sanitizer residuals, preferring to see a small but measurable value right before using the tub.  I personally shoot for 0.5 to 1 ppm the next day, and that takes a dose of 2-3 tsp after using our 525 gallon tub (that gets the levels up to 5 ppm+ half an hour after dose).  If you are using a supplemental sanitizer like Nature2/Frog or ozone you can get by with less, but having a measurable residual is a good indication that you are using enough sanitizer to stay ahead of any nasty invaders.  Since you are not getting any reading, I would try a higher regular dose.

[drober30]

For the first time I had a perfect reading before getting in my tub.

I just was not adding enough.

I will increase the amount added at night till I find that I get a proper reading prior to getting in the tub the next night.

I am using ozone and HS Silver Ion cartridge. I know I'm supposed to be using MPS with these extras but feel more comfortable with Dichlor. You have to use Dichlor anyway and it will oxidize and sanitize at once.

But if I can maintain a proper/constant level of sanitizer then what does shocking do?

Does overdosing/shocking the tub kill off stuff that a proper level of Dichlor won’t?

[Soakin]

...But if I can maintain a proper/constant level of sanitizer then what does shocking do?  Does overdosing/shocking the tub kill off stuff that a proper level of Dichlor won’t?

 If you haven't read it already, the Vermonter post in the FAQ on Doc's site (rhtubs.com) addresses this in detail.  The main reason to shock was addressed by Bill and Vinny:  to oxidize the combined chlorine (chloramines) and any other organic material present in the tub.  The chloramines create what everyone associates with "chlorine smell", but provide no sanitizing effect.  Shocking frees up the chlorine to do its job again.  This can be accomplished with either Dichlor or MPS, but I prefer Dichlor for the reasons you stated (get both oxidation and sanitation) , and one less chem to store.  The "supersanitation" of a chlorine shock, is a side benefit, and at least in theory could help kill off any chlorine resistant organisms that might be present.  IMO the main benefit of MPS is that you can enter the tub shortly after dosing, while a chlorine shock requires several hours before levels drop.   You should also be aware that MPS has a low pH, so regular use may cause your pH to drift down over time.  It may also increase your TDS.

[drober30]

 If you haven't read it already, the Vermonter post in the FAQ on Doc's site (rhtubs.com) addresses this in detail.  The main reason to shock was addressed by Bill and Vinny:  to oxidize the combined chlorine (chloramines) and any other organic material present in the tub.  The chloramines create what everyone associates with "chlorine smell", but provide no sanitizing effect.  Shocking frees up the chlorine to do its job again.  This can be accomplished with either Dichlor or MPS, but I prefer Dichlor for the reasons you stated (get both oxidation and sanitation) , and one less chem to store.  The "supersanitation" of a chlorine shock, is a side benefit, and at least in theory could help kill off any chlorine resistant organisms that might be present.  IMO the main benefit of MPS is that you can enter the tub shortly after dosing, while a chlorine shock requires several hours before levels drop.   You should also be aware that MPS has a low pH, so regular use may cause your pH to drift down over time.  It may also increase your TDS.

Great explanation! Thanks!

You know, I read those posts once over at Doc's and I have been back there several times to re-read them but for the life of me I cant find the FAQ link again.

[jsimo7]

I have looked also and cant find that thread. Does anyone have it stored??

[Vinny]

Go to Doc's site, go to his forum and it's under the FAQ.