Why use Dichlor if spa is covered?

[BigBlue]

My spa is always covered except when I use it, which is usually at night after the sun has set.  So do I still need to use Dichlor with CYA in it.  I thought the only reason you needed CYA was to prevent the chlorine from being broken down by UV rays from the sun.  If the spa is always covered, do I still need to use Dichlor, or can I just use Clorox instead?

[mpkelley20]

The main reason you want some CYA in the tub is because it regulates/controls chlorine strength.  If you had no CYA, the chlorine would be too strong initially and then dissipate very quickly which would make it difficult to maintain some level of sanitizer between the time you add it and the time you use it.  There is some math I've seen that explains what free chlorine levels look like with stabilizer and without and you do want/need stabilizer in order to control the oxidation/breakdown of the chlorine.  Something like 4ppm chlorine with stabilizer is equal to less that 1ppm without stabilizer...

If you want to maintain a minimum level of chlorine (enough to kill stuff right after use and you are using the tub daily), you can probably get away with not using stabilizer but you would need to be testing your water a lot to make sure no baddies are in the water.  I say give it a try and report back how well it works our for you.

[The Wizard of Spas]

You have to use a sanitizer.  It does not have to be DiChlor.  But you have to use a sanitizer of some sort. 

I may be a contrarian on this so here goes...  I don't use any CYA in my tubs and I sell DiChlor.  I also don't use bleach either.

I get all the points made about water chemistry when it comes to hot tubs.  But I also never see anything that takes into consideration the amount of fresh water added.  I know that is too vague to calculate, but I feel that there is enough fresh water added during the life of the fill to make me not worry about CYA if I was concerned.  But again- I am not.

The cover being on the tub, and the lack of bacteria/algae that is free to get in your tub makes me question the need.  Again:  I get the science and all the points made.  I agree with people who do it that way.  Its fine to do it that way.  My thing is:  What is the difference between adding CYA then switching to bleach vs not?  I have tried both ways and it just seems not worth it. I have never seen the ramifications of not doing those extra steps.

I always felt that if you keep your pH, alkalinity and sanitizer level in line, only good things happen.  As your water is drained every 3-4months depending on usage I have never ran into the issues associated with CYA.  And again:  I monitor water chemistry for in ground pools so I understand the bigger picture. 

I don't like bleach as there is too much that can go wrong;  Bleach has a short shelf-life (90 days or less, depending on how much it is jostled, spills can be devistating, etc) and granular chlorine (yes- it also has its downsides) tends to last longer and people can buy it in bulk (a relative term as I consider bulk to be 6lbs for a hot tub).

So I am taking a different approach than many on this site.  But that doesn't mean they are wrong and I am right.  I just think that we are all running the same race:  We all wanna get to the finish line but we all may run the race a different way.

I hope this helps.  Good luck moving forward.

[BullFrogSpasMN]

You have to use a sanitizer.  It does not have to be DiChlor.  But you have to use a sanitizer of some sort. 

I may be a contrarian on this so here goes...  I don't use any CYA in my tubs and I sell DiChlor.  I also don't use bleach either.

I get all the points made about water chemistry when it comes to hot tubs.  But I also never see anything that takes into consideration the amount of fresh water added.  I know that is too vague to calculate, but I feel that there is enough fresh water added during the life of the fill to make me not worry about CYA if I was concerned.  But again- I am not.

The cover being on the tub, and the lack of bacteria/algae that is free to get in your tub makes me question the need.  Again:  I get the science and all the points made.  I agree with people who do it that way.  Its fine to do it that way.  My thing is:  What is the difference between adding CYA then switching to bleach vs not?  I have tried both ways and it just seems not worth it. I have never seen the ramifications of not doing those extra steps.

I always felt that if you keep your pH, alkalinity and sanitizer level in line, only good things happen.  As your water is drained every 3-4months depending on usage I have never ran into the issues associated with CYA.  And again:  I monitor water chemistry for in ground pools so I understand the bigger picture. 

I don't like bleach as there is too much that can go wrong;  Bleach has a short shelf-life (90 days or less, depending on how much it is jostled, spills can be devistating, etc) and granular chlorine (yes- it also has its downsides) tends to last longer and people can buy it in bulk (a relative term as I consider bulk to be 6lbs for a hot tub).

So I am taking a different approach than many on this site.  But that doesn't mean they are wrong and I am right.  I just think that we are all running the same race:  We all wanna get to the finish line but we all may run the race a different way.

I hope this helps.  Good luck moving forward.

I completely agree...I try and keep water-care as simple as humanely possibly...Balance the pH/Alkalinity, add sanitation, maintain clean filters and drain every 90-100 days approximately.  I stress importance of water-care of course but at the end of the day I'm selling fun, family time & relaxation, not a science experiment you need a chemical engineering degree to operate.  And yes I'm fully aware standard household bleach will work and do have a few customers who use it but I personally do no mention it during any point of the sales process...sorry but the stigma of telling someone who just spent 5 figures on a brand new spa to go into the bathroom and grab the stuff you just scrubbed your toilet with and pour it into your spa is not an appealing proposition to me, others mileage may vary and that's fine.

[mpkelley20]

sorry but the stigma of telling someone who just spent 5 figures on a brand new spa to go into the bathroom and grab the stuff you just scrubbed your toilet with and pour it into your spa is not an appealing proposition to me, others mileage may vary and that's fine.

This is why companies take the same basic product, throw it in a fancy container, call it a cool name and sell it for 5x the price. 


Wizard:  what granular chlorine do you use?  Most of the options I see are either dichlor, trichlor or calcium hypochlorite.  Only one of those without CYA is the CH.  I'm sure I am missing others.  Curious as I would consider it for the winter months when I am in a bit more of a hurry to get sanitizer in my tub.

[The Wizard of Spas]

I didn't explain myself correctly.  I use the standard DiChlor just as most everyone else if they are using granulated chlorine in hot tubs.  Sorry- I kinda tend to skip over things.

What I was trying to convey was that I don't factor in CYA into my tub.  I don't test for it nor do I worry about it.  I think - And this is me, and I could be alone on this - that between the combos of the tub being covered 24/7 and the topping off with fresh water, and that 2 people in a hot tub is like 20 people in a pool, so on so forth, the factoring of chlorine loss via CYA is way lower on the list of priorities vs other things. 

In a larger pool with more gallons and more products and longer times to adjust and the exposure to the elements, blah blah blah- Yes, I am totally in tune with CYA factors and how it can devalue your chlorine.

But with hot tubs, since things can burn off so much faster, there is such a steep curve between fractions of ounces, variations between using a tub for 15 mins vs 25 mins, number of people that sit in the tub, quality of testing equipment, etc. that its rather difficult to do the math and feel confident vs stepping back and looking at it from the more macro level.  So I go with broad strokes and make sure that pH, alk and sanitizer levels are where they need to be and then cross any bridges whenever I need to.

Basically its partly because I am lazy.  Yes- Going the extra step and factoring CYA is something that if you did it wouldn't hurt you.  I just look at it this way:  Is the juice worth the squeeze?  I think that there are other variables that are more important vs what you lose from CYA in a hot tub situation.  Add in the bleach factor (life span, loses effectiveness the more it is shaken/jostled and thus less potent, if spilled it just a bad situation, etc) and I could argue you lose just as much vs CYA loss.  The point is- its so convoluted at this point and we are so far down the line that if you have the knowledge at this deep of a level, you are likely going to be fine no matter what you do.