Circulation Pump - are they truly a cost saver?

[Spatech_tuo]

Kinda makes one wonder why it would be advantageous to have ozone introduced via a 24/7 circ pump...

I'm not sure I understand the question as even those who are prefer a 2-speed pump will typically agree that the idea of 24/7 ozone is an advantage of a circ pump. Ozone has no residual, meaning as soon as it’s turned off there is none available, so you want it working as much as possible. In fact, when people with a 2-speed pump want to lower the amount of time the pump is on for filtering I always explain to them that there is a tradeoff as the more they lessen their filtering, the more they lessen the amount of time the ozone is on.

[empolgation]

I'm not sure I understand the question as even those who are prefer a 2-speed pump will typically agree that the idea of 24/7 ozone is an advantage of a circ pump.

Not really a specific question, I just continue to search for answers.
In this case my question would be: why is 24/7 ozone an advantage??

Athough ozone may have no residual (if it did it could be more effective), it needs to be aqueous ("disolved" - not in bubbles) to be effective. I'd like to see some empirical data to support that 24/7 circ pump ozonation is more effective. From what I've seen, at the concentrations that aqueous ozone is introduced into any spa it appears as though the amount of time ozone is introduced is irrelevant. Similar to the take on filtering, 24/7 circ pump is filtering much less water over a longer period of time than the periodic jet pump circ in a shorter period - it's volume not amount of time, where the effectiveness of ozone remains to be seen.

The only sound data I've come across is that the more you have the ozonator running the more often you'll have to maintain it and the more often you'll need to replace it. Also, a most important factor is the system's success in making the ozone usable, in aqueous form; that is in part done by length of time the ozone spends in the contact chamber before it is released into the tub to bubble up to the surface and just add to the air (by the way, careful when you open that cover - you just may get a blast of ozone... hmm is that bad? that lead me to another question, is 24/7 circ ozonation adding more ozone to the air under your cover?).

[Spatech_tuo]

What you need is to mix the ozone with the water as long as possible before it reaches the top surface of the water. A good tub has a contact chamber that may be about 10 feet or so giving the ozone more chance to mix and do its job. Ozone is being drawn thought the tube and into the tub about 6-8 hrs a day for spa with a 2-speed pump and for 24 hrs a day for spas with a circ pump. The fact that the ozone is being input into the chamber for the additional 16 hrs or so is why a circ pump is absolutely an advantage relative to ozone (and I'm only speaking relative to ozone).

[Mendocino101]

Spa tech....

I understand what you are saying about the 24 hour of ozone using the circ pump but if you are moving the water volume in the spa around ten times daily where with the 2 speed pump closer to 60 times even if it is getting ozone only 4 to 8 hours a day the total volume of water would still be more ozone enriched so to speak....as you are filtering more volume...am I wrong to think this....

[empolgation]

The fact that the ozone is being input into the chamber for the additional 16 hrs or so is why a circ pump is absolutely an advantage relative to ozone (and I'm only speaking relative to ozone).

It certainly is an advantage relative to *using* the ozonator more... but again, it is not evidence that it is more effective or "better" relative to sanitizing your spa.

Length of contact chamber does play a small part (as well as other factors) in effectiveness - is a circ pump with a 5 ft chamber better than a jet pump with 25ft? I'm not saying that circ pump ozonation is not advantageous (I don't know, but am interested to find out), I'm just saying that there is no concrete evidence to suggest that it is; just because it's fact that the ozonator is running over a longer period of time does not mean that it is more effective. Just as saying 24/7 circulation alone doesn't mean that it's more effective at filtering.

Mendo, no, you are not wrong to think that way.
It *may* not be an accurate assumption but then again you may be right on. How much effective ozone is each method introducing into the tub? How does volume and velocity of movement effect the effectiveness of a spa ozonator? And again considering the concentrations of aqueous ozone in any spa, does any of the differences matter?

[OnMedic]

OK, I have ready most of this post and now have to pipe up a bit. Here is the reasoning as far as I understrand:

1. Filtering vs. Ozone - Two different functions. Filtering is a function to remove particulate from the water. So yes, most tubs with circ. pump and ozone will cycle, even if only for 30 seconds x 2-3 times daily, to remove the particals/sediment from the water via the filter. Ozone's only function is to act as an oxidizer and kill organic matter. Hence, two very seperate functions.

2. Circ. Pump vs. Intermitten Main Pump - Ozone has a half life of approx 20-40 minutes if I am not mistaken. Ozone is VERY short lasting and must be produced on an ongoing basis, hence the lower chemical concentration (bromine, chlorine etc) of 0.5-1 ppm. If the ozonator only turns on every four to 12 hours (or whatever you may have scheduled), you will be essentially running without your main disinfectant for most of the time between cycles, relying on your lower concentration of chemical, which is only intended as a back-up system.

Bottom Line - If you are using Ozone, you should have a 24/7 Circ pump, or else up your chemical concentration, which defeats the purpose of Ozone!

Hope this all makes sense!

OnMedic

[Spatech_tuo]

Empo,
Certainly you must first be a believer in ozone in order to buy into the fact that the increased ozonation from a 24/7 circ pump is beneficial. IF you are a believer (as my experiences have made me) then a 24/7 circ pump will provide more ozone and do the job better for you. If you are not a believer then you don't care and will save the money by never having an ozonator installed the first place.


Mendo,
A 2-speed pump may give you 5 times the filtering by moving that much more water (or whatever the number may be) but it doesn’t provide 5 times the ozone and over the course of the day you get much more ozonation from a circ pump. Good question but it doesn't work that way.



BTW, you're supposed to believe anything I say as after all, I have Ultimate Member status. Only 796 more posts to get to 1000 to make me a Grand Poobah Member. In reality, I'm not saying you should get a spa with a circ pump because of the increased ozone alone. I was merely responding to the original post relative to how a circ pump benefits you and ozonation is one of them. If you've got a spa with a 2-speed pump or are more a believer in that method then more power to you.

[empolgation]

Makes sense OnMedic  - thanks!

But I'm not convinced of your bottom line.
Do you have any data to support the need to up your concentration of chems soley based on jet pump ozonator versus circ pump? What is the ozone concentration in the tub of a low flow circ pump versus a higher flow jet pump? Seems to me that Mendocino101 is onto something with the volume idea  - it's a race to move that ozone into as much of the water as possible to do its dirty work before it decays.

Hadn't considered the half-life aspect before...
If half-life is 20-40 minutes that would mean that it's potentially around for several hours before it's gone depending on how much you got in there (half-life is the amount of time for half of the ozone to revert to O2: for example, after 40-80 minutes you would still have 25% of your ozone) which would make the difference of how often the ozone is introduced moot. Though I'd imagine ozone half-life is much shorter in a 100+ degree spa, probably around 3-5 minutes depending on the rest of the water's chemistry - meaning it is indeed a race to move it around before it's gone.

2 approches to the same end result??
- Constant ozonation at low volume (water movement)
- Periodic ozonation at a significantly higher volume

[Spatech_tuo]

2 approches to the same end result??
- Constant ozonation at low volume (water movement)
- Periodic ozonation at a significantly higher volume

That's where the misconception comes in. Even though you're getting more flow with the 2-speed pump than the circ pump you're not getting more ozone and you really don't want more as all you'll do is have a big off-gas problem. A spa with a circ pump uses a different injector than one with a 2-speed pump as the orifice size has to change to compensate for flow.
Bottom line, you get much more ozone mixed with the water in a spa with a 24/7 circ pump.  

[empolgation]

Certainly you must first be a believer in ozone in order to buy into the fact that the increased ozonation from a 24/7 circ pump is beneficial. IF you are a believer (as my experiences have made me) then a 24/7 circ pump will provide more ozone and do the job better for you.

Oh I am a believer in ozone - it's just that the answers as to why it's more effective in 24/7 circ pump has not convinced me to believe it. Give me the data to support the bottom line.

My conclusion thus far is that there is no data to support which is more effective either way. If the particular tub has its system designed effectively it makes no relevant difference if it's done with a circ pump or jet pump.
But hey, I'm still learnin', I'm only a full member

Thanks so much for your input, I've learned a lot on this thread.

[Roborph]

 As far as we all know now, this is probably a non issue. Buy a top 6 brand and you'll be ok...

[ebirrane]

Well the 24 hour circulation pump moves water through the chamber more slowly. If a 24/7 pump moves the contents of the tub 10 times a day and intermitent jet pumps move the contents of the tub 60 times a day, then:

1) If the contact chambers are equal
2) If the ozone output is equal

then the water in the contact chamber of a tub with 24/7 pump gets 6 times the contact time than another tub.

To even this out, either:

1) The contact chamber of intermitent, larger pump systems must be 6 times longer or
2) The ozonator in such systems must put out 6 times the ozone.

Am I missing somthing, because this seems obvious to me?  Anyway, that's why I've always felt that a 24/7 slower pump is better for ozonation.

If the water is shooting through the chamber 6 times faster it will be in the contact chamber 1/6 of the time of a slower pump.  When talking about a fixed sanitation method you want water to go as slow as possible by the sanitation method for maximum benefit, to stay in contact with that sanitation method for as long as possible. Great for sanitation, less great for filtration (which is optimized by maximizing the number of passes through the filter)

-Ed

[ZzTop]

Well the 24 hour circulation pump moves water through the chamber more slowly. If a 24/7 pump moves the contents of the tub 10 times a day and intermitent jet pumps move the contents of the tub 60 times a day, then:

1) If the contact chambers are equal
2) If the ozone output is equal

then the water in the contact chamber of a tub with 24/7 pump gets 6 times the contact time than another tub.

To even this out, either:

1) The contact chamber of intermitent, larger pump systems must be 6 times longer or
2) The ozonator in such systems must put out 6 times the ozone.

Am I missing somthing, because this seems obvious to me?  Anyway, that's why I've always felt that a 24/7 slower pump is better for ozonation.

If the water is shooting through the chamber 6 times faster it will be in the contact chamber 1/6 of the time of a slower pump.  When talking about a fixed sanitation method you want water to go as slow as possible by the sanitation method for maximum benefit, to stay in contact with that sanitation method for as long as possible. Great for sanitation, less great for filtration (which is optimized by maximizing the number of passes through the filter)

-Ed

Ed great analysis.

Some manufactures using a circ pump have contact chambers of 6 feet.
I have seen Mfg without circ pumps using up to 25 foot contact chambers.

I have never seen specs on the output of ozone on various makes nor the differences between UV, cd chip, and plasma cell, relative to their output.

I am interested in the new plasma cell type to see if it will last, maintanence free for 6 - 7 years and its cost compared to the other two systems.

I guess time will tell.

[tony]

I also like the fact that I heat through the circ pump....quiet and efficient....main pump doesn't have to come on every time the heater does.

[Wisoki]

I think you are greatly overstating the "half life" of ozone, to my knowledge it is 20 to 40 seconds. Since it doesn't become a liquid and mix with the water, but is a gas that very quickly raises out of the water, regardless of "contact chamber" and forms a gaseous layer between the cover and water surface. Ozone should NEVER be considered a "Primary" sanitizer. It is has and always will be a suplimental system to bromine, chlorine or biguanides. Even when used in conjunction with a mineral purifier i.e. N2, spa frog, etc... it is secondary to the table spoon per 100 gallons of chlorine and regular addition of shock.  

2. Circ. Pump vs. Intermitten Main Pump - Ozone has a half life of approx 20-40 minutes if I am not mistaken. Ozone is VERY short lasting and must be produced on an ongoing basis, hence the lower chemical concentration (bromine, chlorine etc) of 0.5-1 ppm. If the ozonator only turns on every four to 12 hours (or whatever you may have scheduled), you will be essentially running without your main disinfectant for most of the time between cycles, relying on your lower concentration of chemical, which is only intended as a back-up system.

OnMedic