Original > Hot Tub Forum
Circulation Pump - are they truly a cost saver?
Wisoki:
Incorrect, the exact same mazi injector is used.
--- Quote ---
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.
--- End quote ---
Spatech_tuo:
--- Quote ---Incorrect, the exact same mazi injector is used.
--- End quote ---
Actually it is correct, as there are different colored Mazzi injectors out there. The colors denote the orifice size at the intake as the flow difference between a circ pump and a 2-speed pump creates varying venturis therefore requiring a different orifice size to control he amount of ozone being drawn in. If you're only dealing with 2-speed pumps you probably only use one type but a circ pump does require a different mazzi than a 2-speed pump if you want to match the systems properly.
empolgation:
--- Quote --- 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.
--- End quote ---
I think you meant to say 6 times less, no?
--- Quote ---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.
--- End quote ---
The big assumption with this analysis is that all of the water moved through the jet pump moves through the ozonator chamber. This is wrong. For example, with one system I am familiar (through obsevation of equipment), water coming from the filters through the pump gets diverted into 2 directions, ~ 1 1/2 inch pipe to the heater and ~ 1/2 inch tube to the contact chamber, so somewhere around 1/8 of the water flows through the contact chamber.
The question/consideration of volume and water movement with respect to ozonation effectiveness would mostly apply to the off-gas coming out of the ozonator jet. The greater the water movement in the tub the greater the chance of putting it to use before it reaches the surface.
As I've said before with the legal concentration of ozone allowed in any spa the differences between the two methods are probably insignificant. As Zz concurred, no specs, no data... only time will tell.
Starlight:
--- Quote ---
The question/consideration of volume and water movement with respect to ozonation effectiveness would mostly apply to the off-gas coming out of the ozonator jet. The greater the water movement in the tub the greater the chance of putting it to use before it reaches the surface.
As I've said before with the legal concentration of ozone allowed in any spa the differences between the two methods are probably insignificant. As Zz concurred, no specs, no data... only time will tell.
--- End quote ---
First off, I know of NO hard data on ozone performance in spas, so we're all really guessing at this point. Let me correct one misconception-- bubbles are NOT dissolved (aqueous) ozone and are therefore irrelevant to discussions about oxidizing/sanitizing. My take, as someone who has done a fair amount of lab chemistry work: you'd want a continuous injection of ozone with a flow rate slow enough to ensure:good contact chamber time and minimization of turbulance and high-speed impacts with nucleating material that would cause the ozone to outgas from solution. Think of pouring a soda quickly over ice and how much foam is created. Even if the ozone stays in solution when you move the water quickly, you would effectively be diluting the ozone in a greater volume of water. You won't find many pathogens in a teaspoon of straight bleach, but dilute that tablespoon in a spa and its sanitizing power is lost. Because the half-life of ozone is so short and the rate of ozone production relatively low compared to water volume, any dissolved ozone would rapidly be depleted from the water and therefore the water will continuously be capable of accepting more ozone. If additional ozone is not continuously supplied, you aren't taking full advantage of the ozonator. Some assumptions I've made:
1. Ozone is actually oxidizing and/or sanitizing in meaningful amounts
2. Demand for ozone always exceeds supply
3. Ozone is produced at a fixed rate
Until someone does some good studies on use of ozone in spas, how an ozonator is best used will come down to personal belief.
Starlight
Mendocino101:
Starlite,
I appreciate your comments. Are you saying that for example that if you are using a high flow system.( 2 speed pump) and moving more water but doing so with an adequate contact chamber say 20 ft or greater than it is effective ? or are you saying that for spa use the slower moving circ pumps does offer better ozone zanitation....or that both are truly still up for debate as to which is significantly more effective.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version