The PB is going to install a Prozone ozonator, just want to make sure he does it right. I know the water is drawing from before the filter and the return is after the heater, but should it be before the SWG or after?
Any one who has a ozonator and SWG?
- Thread starter Ke
- Start date
The ozone should not be introduced before or after the cell; it should be introduced on a separate return using a venturi mixer.
The general consensus is that ozonators don't really do much good in a residential pool. With a properly sized SWG, you are going to have all the sanitizing power you'll need.
Just a thought, but could you get some other upgrade instead - colored lights or something along those lines? The ozonator certainly won't do any harm, though.
Just a thought, but could you get some other upgrade instead - colored lights or something along those lines? The ozonator certainly won't do any harm, though.
Ke,
I do not have SWG.
I think Mr9 is trying to say that if you have SWG, after/downstream the cell you you will get very high chlorine level, and if you inject ozone there, your chlorine maybe be oxidized or reduced because where ozone venturi injector is at, downstream of that, the ozone is very concentrated. If you inject ozone before the salt cell, you may ruin the salt cell and I don't know if bubbles will interfere with a salt cell.
I have sand filter and cartridge plumbed in series and choose to install the saddle/Tee with the venturi before the cartridge not the sand. The venture injector works on pressure difference to generate the vilolent mixing of ozone into water. There are two saddles or Tee from the Prozone. I get a Tee, you may get a saddle, both work the same. The Tee/saddle before a filter is where the blue venturi injector will be located, from there it has a transparent hose to flow water and ozone bubbles to another Tee/saddle after the cartridge filter. So the actual piping that gets ozonated water is the one after the cartridge, at the second Tee/saddle.
Prozone advice that minimum of 8 feet pipe length from the second Tee/saddle before that water exit out at the pool inlet nozzle. This is because the longer the ozone bubbles stay in the pipe, the better the ozone will mix with water and less wasted ozone as bubbles that burp out into the air. If you have short pipe length after the Tee/Saddle I am sure you will get decreased ozone effectivity because more ozone will be out as air ( off gass ) instead of being soluble in water and also less contact time of ozone to the water. I did play with a PZ2-4 Prozone ( 2 gram per hour )and a compressor with short hose length for fun. The compressor is needed because I can't use the venturi, venturi only work with a pump and pressure difference of 5-10 psi, that is why a filter is the best way to get that pressure difference. I smell ozone gas strongly, because even though I use aquarium sort of aerator stone to try to produce air bubbles, the ozone mixing with water is only like 1 feet water length/depth because I use a 120 quart cool box for the test, and there is no water pressure to assist ozone mixing with water. Any water that exit from a filter, depending of length of pipe to final pool inlet nozzles, is under pressure from the resistance of the waterflow, the longer the pipe and the faster the waterflow, the higher the pressure ( Its resistance actuallly ), it does keep ozone bubble smaller size due to pressure. Finer bubbles is a better for ozone mixing.
I have 6 inlet nozzles in my pool, naturally the closest one to the filter will have better water flow and more ozone bubbles escaping there, the first 3 will be with most bubbles..... progressing to less bubbles as the pipe goes longer. The other three will be almost without bubbles. So I thought probably all the ozone bubbles got thrown out at inlet nozzles 1 - 3 and no balance for 4 -6.
However when I plug the #5 or #6, I can see so much bubbles coming out from #4, but when I plug #4 I don't see similiar increase of bubble at #5 or #6. Even when I plug no #1, #2, or #3, the #5 or #6 do not get significant any bubble increase. I suspect that with almost a 100 feet distance travelled from the point of ozone injection, I am looking at bubbles that have probably more succesfully being absorbed by the water at #5 & #6 nozzles. I may be wrong though.
So if you do install a dedicated piping and inlet nozzle for the ozononator, you may need a compressor, because without pressure difference the venturi won't suck air from your ozonator. Depending on your piping, you may still get away without the compressor though. Install first prozone Tee/Saddle before filter, install T pipe before a cell, so that partial waterflow goes to SWG cell, the other goes to pool direct with second prozone saddle installed on dedicated piping. You may want to install a valve to adjust waterflow before the second saddle ( ozone dedicated piping ). Best the valve be before second saddle because if the valve has o-rings made of rubber, the ozone will ruin it fast. This valve is actually to set up the ozone concentration. The slower the waterflow per minute, the higher the zone concentration per liter of water, thus the oxidizing power is greater. If you can extend the piping length for the dedicated ozone plumbing, the better for you, more abosorbtion of ozone in the water and less smell given out by the ozone bubbles when it burbs out in your pool...meaning the ozone have oxidize as much as it could, thru longer water flow and its decays itself too. Remember, killing power of all oxidizer is contact time and concentration. So less concentration, then make the contact time longer. Since the ozone is short lived and gass out as bubbles when it reaches your pool, in reality.... it does it work mostly WHILE in the pipe where it keep being in contact with water. This is why commercial installation will use 2-3 minutes contact chamber, to maximize contact time.
If the installer do not understand how ozone works, the net effectivity for you will not be maximum merely from unsuitable installation. This is why end user may find ozone not worth the money. You must also remember that the actual overall waterflow on that dedicated ozone plumbing is only so many percent of the pool water. This will also translate to bulk of water in the pool to get ozonated at a slow rate, maybe only after 7+ turnover or so, then the entire bulk of your pool have been ozonated...once...only once. This is why some people use separate small pump for ozone and run it 24/7 on dedicated plumbing. If you do that, best install a medium size cartridge filter, you are already pumping water, might as well filter it to save electricity bill.
Which model is yours and what size is your pool ? Its easy to tell the output. Per every UV lamp module, its is 0.5grams per hour. The UV lamp is sort of epoxy plastic construction, some smell maybe produced when used less than 50 hours. Do not get confused by that smell and think its ozone, its the new chemical smell of that lamp. After 50 hours the smell is gone, that's what I notice with mine. Sniff on one of the hose from the ozonator when its off, you will know what I mean.
Hope this helps and good luck.
I do not have SWG.
I think Mr9 is trying to say that if you have SWG, after/downstream the cell you you will get very high chlorine level, and if you inject ozone there, your chlorine maybe be oxidized or reduced because where ozone venturi injector is at, downstream of that, the ozone is very concentrated. If you inject ozone before the salt cell, you may ruin the salt cell and I don't know if bubbles will interfere with a salt cell.
I have sand filter and cartridge plumbed in series and choose to install the saddle/Tee with the venturi before the cartridge not the sand. The venture injector works on pressure difference to generate the vilolent mixing of ozone into water. There are two saddles or Tee from the Prozone. I get a Tee, you may get a saddle, both work the same. The Tee/saddle before a filter is where the blue venturi injector will be located, from there it has a transparent hose to flow water and ozone bubbles to another Tee/saddle after the cartridge filter. So the actual piping that gets ozonated water is the one after the cartridge, at the second Tee/saddle.
Prozone advice that minimum of 8 feet pipe length from the second Tee/saddle before that water exit out at the pool inlet nozzle. This is because the longer the ozone bubbles stay in the pipe, the better the ozone will mix with water and less wasted ozone as bubbles that burp out into the air. If you have short pipe length after the Tee/Saddle I am sure you will get decreased ozone effectivity because more ozone will be out as air ( off gass ) instead of being soluble in water and also less contact time of ozone to the water. I did play with a PZ2-4 Prozone ( 2 gram per hour )and a compressor with short hose length for fun. The compressor is needed because I can't use the venturi, venturi only work with a pump and pressure difference of 5-10 psi, that is why a filter is the best way to get that pressure difference. I smell ozone gas strongly, because even though I use aquarium sort of aerator stone to try to produce air bubbles, the ozone mixing with water is only like 1 feet water length/depth because I use a 120 quart cool box for the test, and there is no water pressure to assist ozone mixing with water. Any water that exit from a filter, depending of length of pipe to final pool inlet nozzles, is under pressure from the resistance of the waterflow, the longer the pipe and the faster the waterflow, the higher the pressure ( Its resistance actuallly ), it does keep ozone bubble smaller size due to pressure. Finer bubbles is a better for ozone mixing.
I have 6 inlet nozzles in my pool, naturally the closest one to the filter will have better water flow and more ozone bubbles escaping there, the first 3 will be with most bubbles..... progressing to less bubbles as the pipe goes longer. The other three will be almost without bubbles. So I thought probably all the ozone bubbles got thrown out at inlet nozzles 1 - 3 and no balance for 4 -6.
However when I plug the #5 or #6, I can see so much bubbles coming out from #4, but when I plug #4 I don't see similiar increase of bubble at #5 or #6. Even when I plug no #1, #2, or #3, the #5 or #6 do not get significant any bubble increase. I suspect that with almost a 100 feet distance travelled from the point of ozone injection, I am looking at bubbles that have probably more succesfully being absorbed by the water at #5 & #6 nozzles. I may be wrong though.
So if you do install a dedicated piping and inlet nozzle for the ozononator, you may need a compressor, because without pressure difference the venturi won't suck air from your ozonator. Depending on your piping, you may still get away without the compressor though. Install first prozone Tee/Saddle before filter, install T pipe before a cell, so that partial waterflow goes to SWG cell, the other goes to pool direct with second prozone saddle installed on dedicated piping. You may want to install a valve to adjust waterflow before the second saddle ( ozone dedicated piping ). Best the valve be before second saddle because if the valve has o-rings made of rubber, the ozone will ruin it fast. This valve is actually to set up the ozone concentration. The slower the waterflow per minute, the higher the zone concentration per liter of water, thus the oxidizing power is greater. If you can extend the piping length for the dedicated ozone plumbing, the better for you, more abosorbtion of ozone in the water and less smell given out by the ozone bubbles when it burbs out in your pool...meaning the ozone have oxidize as much as it could, thru longer water flow and its decays itself too. Remember, killing power of all oxidizer is contact time and concentration. So less concentration, then make the contact time longer. Since the ozone is short lived and gass out as bubbles when it reaches your pool, in reality.... it does it work mostly WHILE in the pipe where it keep being in contact with water. This is why commercial installation will use 2-3 minutes contact chamber, to maximize contact time.
If the installer do not understand how ozone works, the net effectivity for you will not be maximum merely from unsuitable installation. This is why end user may find ozone not worth the money. You must also remember that the actual overall waterflow on that dedicated ozone plumbing is only so many percent of the pool water. This will also translate to bulk of water in the pool to get ozonated at a slow rate, maybe only after 7+ turnover or so, then the entire bulk of your pool have been ozonated...once...only once. This is why some people use separate small pump for ozone and run it 24/7 on dedicated plumbing. If you do that, best install a medium size cartridge filter, you are already pumping water, might as well filter it to save electricity bill.
Which model is yours and what size is your pool ? Its easy to tell the output. Per every UV lamp module, its is 0.5grams per hour. The UV lamp is sort of epoxy plastic construction, some smell maybe produced when used less than 50 hours. Do not get confused by that smell and think its ozone, its the new chemical smell of that lamp. After 50 hours the smell is gone, that's what I notice with mine. Sniff on one of the hose from the ozonator when its off, you will know what I mean.
Hope this helps and good luck.
I agree with Sean that an ozonator is usually unnecessary with a SWCG.
If you are going to get the ozonator: It is my opinion that the ozonator should be placed on a separate line than the cell. However, I did contact two ozone manufacturers today to get their advice. They tell me that there is no problem with placing the ozonator after the cell. A tech support person even told me about a new salt cell with an ozone injector built into the cell. It is supposed to mix ozone and salt water in the cell for a better result.
If you are going to get the ozonator: It is my opinion that the ozonator should be placed on a separate line than the cell. However, I did contact two ozone manufacturers today to get their advice. They tell me that there is no problem with placing the ozonator after the cell. A tech support person even told me about a new salt cell with an ozone injector built into the cell. It is supposed to mix ozone and salt water in the cell for a better result.
Hi Spp,
Thanks for the detailed reply. My ozonator is the Prozone PZ7 2HO, my fiberglass pool is 8500 gals. I did call Prozone today, I've confirmed that the first clamp/venturi goes before the filter and the second clamp goes after the swg. My equipment pad is about 70 ft from the pool, so I should get good mixing of ozone inside the pipes. Now my concern is that there are a few Jandy valves along the pipes, so is there any rubber in the valves to be ruined ?
Thanks for the detailed reply. My ozonator is the Prozone PZ7 2HO, my fiberglass pool is 8500 gals. I did call Prozone today, I've confirmed that the first clamp/venturi goes before the filter and the second clamp goes after the swg. My equipment pad is about 70 ft from the pool, so I should get good mixing of ozone inside the pipes. Now my concern is that there are a few Jandy valves along the pipes, so is there any rubber in the valves to be ruined ?
Hi Ke,
Your model is a 1 gram unit PER HOUR, with your pool size at 8500 gallons and depending on your water flow, you may get decent concentration. I mean decent is that I hope you may get the result I am getting. My pump is slow at 12 hours turnover, so I get more concentration than a calculation based on 8hr per pool water turnover.
You can calculate your ozone concentration roughly this way :
I am a metric guy and since the ozone output is in grams, that is easier for me.
1,000 mg is 1 gram
1,000 mg is the same as 1,000 ppm
So your ozonator is 1,000 gram divided by 60 minutes = 16.6 PPM per minute
Whatever your pump water flow is in gallons per minute, you times 3.78 you get liter
So if your PB set your pool at 8 hours per turnover, your pump flow is about 18 gallons per minute real time.
18 x 3.78 = 68 liters per minute
If 6 hours per turnover, you are getting 24 GPM or 90 liters per minute
If 5 hours per turnover, you are getting 28 GPM or 105 liters per minute
8 hours turnover = 16.6 ppm divided by 68 liters = 0.24 ppm per minute ( mine is 0.176 ppm per minute )
6 hours turnover = 16.6 ppm divided by 90 liters = 0.18 ppm per minute
5 hours turnover = 16.6 ppm divided by 105 liters = 0.15 ppm per minute
EDIT *** My ozone level is 2,000 mg divided by 60 minutes divided by waterflow 189 liters per minute, so it should be 0.176 ppm. What I wanted to do later with one additional 2grm ozonator is at least 0.30ppm, but not now, sorry ***EDIT
I am not saying my calculation is correct, but I have an ozone system that works for me at 0.3ppm concentration based on 28*Celcius water. I have not done any bacterial count, I did get improved clarity. Improved clarity is what you are expecting too...right ? I know its not a smart way of saying this but the chorine chart level in this forum database showed that it takes more disinfection to keep algae away than to kill bacteria. I don't know if Gardia and Cypto is calculated there. Ozone is not very effective at keeping algae away, please know that. So in other words ( and I can be wrong since I am no expert ), if our filtration quality is the same and all other contamination level being the same, my pool water being clearer than yours by using ozone and also WE maintaine chlorine FC level suitable to OUR CYA level, my pool is technically more hygienic than yours. In theory. Unless we both do bacteria count, there is no other way to disprove otherwise. Again in theory, I had choosen quite a suitable unit for my application. At least I believe so by that improved clarity. My pool is only 35K gallon and my Prozone PZ2-4V is a 100k gallon model in their table. I know don't want too small a model. My pump flow being slow is actually a benefit. I am planning to add another 2 gram per hour unit soon if it is confirmed that venturi injector can take 4 gram per hour.
Now for some rough calculation for temperature compensation
Assuming that my 0.3ppm per liter is a good measure for ozone concentration at 28-29* C, you must compensate for lower water temperature. If your pool water is 20*C ( gee, I will die at this water temp ), you may loose up to 50% of what effectivity I am getting at 29 - 29*C. If your water temp is 25 *C ( I still can't swim happily at this temp ) , you may loose 30%, compared to me. I don't know your water temp swing. For me 28*C is lowest all year round.
So please adjust accordingly the water temperature you are at and the water flow your pool is doing.
Hence this is another factor to why in your cooler climate, installing ozone have really not work well for most people. Undersized ozone generator and cool water = less effectivity.
My logic tells me, with such a short half life of ozone and residential pool not having contactor tank, you guys in cooler water and residential set up must pay more $$ in ozone power than me in 28 *C water or see no proper result from ozone. You and I only have one similiarity, our contact time is short. I too got NO contactor tank. Like chlorine, once you go below a certain level too low, algae starts to bloom or pathogen killing will not be effective BUT chlorine has residual, meaning time is on chorine side but almost zero for ozone. At least chlorine can compensate low concentration ( we disregard CYA relation for the time being ) by being there by the hours. Ozone doesn't linger longer than 20 minutes at 20*Celcius stated the table. 20 minutes is useless in my opinion for us who do not have contactor tank to reap that 20 minutes half-life benefits, so ozone in your pipes is the only effective time you got. So I think you can figure out now why many residential ozone unit in use that probably gives no obvious beneficial effect to cooler climates user.... they may actually has an undersized unit to begin with.
To make your ozone effective, you must know its limitations. It is unfair to say that generally ozone is not worth the investment in an outdoor pool, it will be fairer to ask : Are you willing to spend the extra money to make it effective for your specific environment and water flow ? In the end is about the $$ budget.
Take a look at this :
http://???.cdc.gov/healthyswimming/chlorine_timetable.htm
Change ??? to www
And this, table 2
http://???.ozoneapplications.com/info/disinfection.htm
Change ??? to www
Take a look at that Table 2.
Giardia and Crypto is not what we are after, its obviously too tough but ozonation on resindential unit power level but FC may assist hitting it after ozonation. Richard ( Chem Geek ) knows better than me on this.
Now I want to calculate our possible contact time senario.
I can't get the usual online pipe calculator to work on this Vista based lap top. As far as I recalled, my water flow is 9 feet per second. Its on the "fast" category, which is not too good but Mas985 said its OK for PVC. Pool pump manufacturer will suggest that we get 6 feet per second as the upper limit. Hayward stated that. My pool plumbing is 100 feet at least. I will take a 75 feet as average, since there are six inlet nozzles in the pool and the closer ones will burb out ozone gas faster than the further ones. So if my water flow is 9 feet per second, in theory my ozone got only 8.3 seconds contact time.
So, if 0.3ppm of ozone is based on per minute, with only 8.3 seconds contact time, I am actually having ozone disinfection reduced by 7.2. So 0.3 divided by 7.2 = 0.042 ppm per liter per minute equivalent.
If you look a table 2 for ozone, I kill E.Coli ( 0.02 ppm ) for sure and high probability for rotavirus ( 0.006 - 0.06 ppm )
If say I have a 5 feet per second waterflow and 75 feet pipes, I will get 15 seconds contact. So I must reduce my ozone disinfection value by 4. So, 0.3ppm divided by 4 = 0.075 ppm per liter minute equivalent. This is more potent.
Someone who knows CT value better may correct me on this one.
I am just showing you the potential mistake if someone uses ozone and do not calculate all these factors.
To what possibility that I may actually got dissolved ozone in the water that exited my 6 inlet return nozzles, I won't know until I do a test. If there are dissolved ozone in that water, that means its all for the better for me since that means I probably get more disinfection quality from the ozone. There is a table that tells you at what temperature and at what percentage the ozone can dissolved in water to be residual. For my case, I will lean on zero residual for dissolved ozone just so that I do not over rated my unit. For my own fun and test, I will soon increase ozonation for my pool to the extend that I can smell any ozone on the bubbles that exited my pool inlet return nozzle. As long as if no smell, I will keep increasing the ozone level. I don't want to add ozone destruct chamber or the like. I also do not want ozone poisoning...
I read of one spa manufacturer that uses 35 foot contactor pipe ( haven spa I think ) with mazzei injector just to get longer contact time, perhaps its like a mini contactor tank.. and he use a 24/7 pump with filters. He is using a corona discharge unit, which means at least 2 grams per hour or so. Anyhow the spa turnover is at 2 hours or less much less. That spa has some serious killing power. I also believe his design is based on the fact that he does not want the ozone burping ozone gas in the spa and irritate the user, hence that long pipe may have allowed good absorption. I do not know if he has de-gass chamber or the like to vent ozone if there is still remaining potent ones as gas.
My advice to you is, check your pump flow in GPM and what is your average pool temperature. If the calculation shows that you are getting low concentration, you can add one more unit of your 1 gram model and have it parallel. You do not need another venturi injector. The blue venturi injector from Prozone can inject 2 gram per hour for me, so I am like having 2 of your units packed as one. You can have two units on separate switch. In times you think you need more, turn both on. All you need is a "Tee" that shares the output of two units as one.
While at it, since the UV lamp ozone hits 02 and convert it to 03 and I believe the same problem will occur if you do not keep the UV lamp clean the way UV lamp for water disinfection is to be maintained, you will loose effectivity. Any dust or dirt build up will refract the UV light from doing its proper work. You can't dismantle that Prozone UV lamp cartridge to have it clean. The best way is to use an air filter as prevention. See my attached photo. That is a car crankcase air filter. Very cheap and free flow. All you need is a bit of work for the hose barb fitting the air hose.
I too have one valve that has 2 rubber o-rings which the ozone must flow thru. I will have to change the rubber o-ring maybe once a year or so, I am not sure yet. Mine can be removed easy. I don't know if Jandy uses rubber or special grade o-ring which is ozone resistant. However be happy that ozone dissolved in water is not as damaging as ozone in air . For example for PVC, ozone gas version will attack PVC but ozone dissolved in water, a PVC pipe still can be used. This is a table I got from a commercial ozone manufacturer, not pool its for water treatment. Download here :
http://???.mksinst.com/docs/UR/astexozonedata.pdf
Change the ??? to www
Hope you get the ozone benefit the way I do.
Cheers
Your model is a 1 gram unit PER HOUR, with your pool size at 8500 gallons and depending on your water flow, you may get decent concentration. I mean decent is that I hope you may get the result I am getting. My pump is slow at 12 hours turnover, so I get more concentration than a calculation based on 8hr per pool water turnover.
You can calculate your ozone concentration roughly this way :
I am a metric guy and since the ozone output is in grams, that is easier for me.
1,000 mg is 1 gram
1,000 mg is the same as 1,000 ppm
So your ozonator is 1,000 gram divided by 60 minutes = 16.6 PPM per minute
Whatever your pump water flow is in gallons per minute, you times 3.78 you get liter
So if your PB set your pool at 8 hours per turnover, your pump flow is about 18 gallons per minute real time.
18 x 3.78 = 68 liters per minute
If 6 hours per turnover, you are getting 24 GPM or 90 liters per minute
If 5 hours per turnover, you are getting 28 GPM or 105 liters per minute
8 hours turnover = 16.6 ppm divided by 68 liters = 0.24 ppm per minute ( mine is 0.176 ppm per minute )
6 hours turnover = 16.6 ppm divided by 90 liters = 0.18 ppm per minute
5 hours turnover = 16.6 ppm divided by 105 liters = 0.15 ppm per minute
EDIT *** My ozone level is 2,000 mg divided by 60 minutes divided by waterflow 189 liters per minute, so it should be 0.176 ppm. What I wanted to do later with one additional 2grm ozonator is at least 0.30ppm, but not now, sorry ***EDIT
I am not saying my calculation is correct, but I have an ozone system that works for me at 0.3ppm concentration based on 28*Celcius water. I have not done any bacterial count, I did get improved clarity. Improved clarity is what you are expecting too...right ? I know its not a smart way of saying this but the chorine chart level in this forum database showed that it takes more disinfection to keep algae away than to kill bacteria. I don't know if Gardia and Cypto is calculated there. Ozone is not very effective at keeping algae away, please know that. So in other words ( and I can be wrong since I am no expert ), if our filtration quality is the same and all other contamination level being the same, my pool water being clearer than yours by using ozone and also WE maintaine chlorine FC level suitable to OUR CYA level, my pool is technically more hygienic than yours. In theory. Unless we both do bacteria count, there is no other way to disprove otherwise. Again in theory, I had choosen quite a suitable unit for my application. At least I believe so by that improved clarity. My pool is only 35K gallon and my Prozone PZ2-4V is a 100k gallon model in their table. I know don't want too small a model. My pump flow being slow is actually a benefit. I am planning to add another 2 gram per hour unit soon if it is confirmed that venturi injector can take 4 gram per hour.
Now for some rough calculation for temperature compensation
Assuming that my 0.3ppm per liter is a good measure for ozone concentration at 28-29* C, you must compensate for lower water temperature. If your pool water is 20*C ( gee, I will die at this water temp ), you may loose up to 50% of what effectivity I am getting at 29 - 29*C. If your water temp is 25 *C ( I still can't swim happily at this temp ) , you may loose 30%, compared to me. I don't know your water temp swing. For me 28*C is lowest all year round.
So please adjust accordingly the water temperature you are at and the water flow your pool is doing.
Hence this is another factor to why in your cooler climate, installing ozone have really not work well for most people. Undersized ozone generator and cool water = less effectivity.
My logic tells me, with such a short half life of ozone and residential pool not having contactor tank, you guys in cooler water and residential set up must pay more $$ in ozone power than me in 28 *C water or see no proper result from ozone. You and I only have one similiarity, our contact time is short. I too got NO contactor tank. Like chlorine, once you go below a certain level too low, algae starts to bloom or pathogen killing will not be effective BUT chlorine has residual, meaning time is on chorine side but almost zero for ozone. At least chlorine can compensate low concentration ( we disregard CYA relation for the time being ) by being there by the hours. Ozone doesn't linger longer than 20 minutes at 20*Celcius stated the table. 20 minutes is useless in my opinion for us who do not have contactor tank to reap that 20 minutes half-life benefits, so ozone in your pipes is the only effective time you got. So I think you can figure out now why many residential ozone unit in use that probably gives no obvious beneficial effect to cooler climates user.... they may actually has an undersized unit to begin with.
To make your ozone effective, you must know its limitations. It is unfair to say that generally ozone is not worth the investment in an outdoor pool, it will be fairer to ask : Are you willing to spend the extra money to make it effective for your specific environment and water flow ? In the end is about the $$ budget.
Take a look at this :
http://???.cdc.gov/healthyswimming/chlorine_timetable.htm
Change ??? to www
And this, table 2
http://???.ozoneapplications.com/info/disinfection.htm
Change ??? to www
Take a look at that Table 2.
Giardia and Crypto is not what we are after, its obviously too tough but ozonation on resindential unit power level but FC may assist hitting it after ozonation. Richard ( Chem Geek ) knows better than me on this.
Now I want to calculate our possible contact time senario.
I can't get the usual online pipe calculator to work on this Vista based lap top. As far as I recalled, my water flow is 9 feet per second. Its on the "fast" category, which is not too good but Mas985 said its OK for PVC. Pool pump manufacturer will suggest that we get 6 feet per second as the upper limit. Hayward stated that. My pool plumbing is 100 feet at least. I will take a 75 feet as average, since there are six inlet nozzles in the pool and the closer ones will burb out ozone gas faster than the further ones. So if my water flow is 9 feet per second, in theory my ozone got only 8.3 seconds contact time.
So, if 0.3ppm of ozone is based on per minute, with only 8.3 seconds contact time, I am actually having ozone disinfection reduced by 7.2. So 0.3 divided by 7.2 = 0.042 ppm per liter per minute equivalent.
If you look a table 2 for ozone, I kill E.Coli ( 0.02 ppm ) for sure and high probability for rotavirus ( 0.006 - 0.06 ppm )
If say I have a 5 feet per second waterflow and 75 feet pipes, I will get 15 seconds contact. So I must reduce my ozone disinfection value by 4. So, 0.3ppm divided by 4 = 0.075 ppm per liter minute equivalent. This is more potent.
Someone who knows CT value better may correct me on this one.
I am just showing you the potential mistake if someone uses ozone and do not calculate all these factors.
To what possibility that I may actually got dissolved ozone in the water that exited my 6 inlet return nozzles, I won't know until I do a test. If there are dissolved ozone in that water, that means its all for the better for me since that means I probably get more disinfection quality from the ozone. There is a table that tells you at what temperature and at what percentage the ozone can dissolved in water to be residual. For my case, I will lean on zero residual for dissolved ozone just so that I do not over rated my unit. For my own fun and test, I will soon increase ozonation for my pool to the extend that I can smell any ozone on the bubbles that exited my pool inlet return nozzle. As long as if no smell, I will keep increasing the ozone level. I don't want to add ozone destruct chamber or the like. I also do not want ozone poisoning...
I read of one spa manufacturer that uses 35 foot contactor pipe ( haven spa I think ) with mazzei injector just to get longer contact time, perhaps its like a mini contactor tank..
and he use a 24/7 pump with filters. He is using a corona discharge unit, which means at least 2 grams per hour or so. Anyhow the spa turnover is at 2 hours or less much less. That spa has some serious killing power. I also believe his design is based on the fact that he does not want the ozone burping ozone gas in the spa and irritate the user, hence that long pipe may have allowed good absorption. I do not know if he has de-gass chamber or the like to vent ozone if there is still remaining potent ones as gas.My advice to you is, check your pump flow in GPM and what is your average pool temperature. If the calculation shows that you are getting low concentration, you can add one more unit of your 1 gram model and have it parallel. You do not need another venturi injector. The blue venturi injector from Prozone can inject 2 gram per hour for me, so I am like having 2 of your units packed as one. You can have two units on separate switch. In times you think you need more, turn both on. All you need is a "Tee" that shares the output of two units as one.
While at it, since the UV lamp ozone hits 02 and convert it to 03 and I believe the same problem will occur if you do not keep the UV lamp clean the way UV lamp for water disinfection is to be maintained, you will loose effectivity. Any dust or dirt build up will refract the UV light from doing its proper work. You can't dismantle that Prozone UV lamp cartridge to have it clean. The best way is to use an air filter as prevention. See my attached photo. That is a car crankcase air filter. Very cheap and free flow. All you need is a bit of work for the hose barb fitting the air hose.
I too have one valve that has 2 rubber o-rings which the ozone must flow thru. I will have to change the rubber o-ring maybe once a year or so, I am not sure yet. Mine can be removed easy. I don't know if Jandy uses rubber or special grade o-ring which is ozone resistant. However be happy that ozone dissolved in water is not as damaging as ozone in air . For example for PVC, ozone gas version will attack PVC but ozone dissolved in water, a PVC pipe still can be used. This is a table I got from a commercial ozone manufacturer, not pool its for water treatment. Download here :
http://???.mksinst.com/docs/UR/astexozonedata.pdf
Change the ??? to www
Hope you get the ozone benefit the way I do.
Cheers
Attachments
1000 mg is not 1000 ppm. 1000 mg/L is 1000 ppm. That is, parts-per-million is the same as milligrams per liter (assuming the water density doesn't significantly change with what's in it and ignoring small pure water density differences with temperature).
For concentration, you figure 1 gram per hour and divide this (1000 mg) by the number of liters flowing through the ozonator per hour. Using the 8 hour turnover time for the 8500 gallons, this is 4022 liters per hour. So that's 1000mg/4022L = 0.25 ppm. If the contact time is only 8.3 seconds as you've indicated, then this is a CT (concentration in ppm times time in minutes) value of 0.25 * 8.3/60 = 0.035 which is enough to give 99% kill rates for most bacteria and viruses, but not the protozoan cysts (Giardia and Cryptosporidium).
Higher levels of ozone can of course be used, but the above calculation is why UV is preferred as a method to inactivate the protozoan cysts. However, unless your pool is used by a lot of different people and these people swim when sick and have fecal accidents without telling you (or you noticing), I wouldn't worry about it.
Since ozone (at the concentration and contact time noted above) isn't any better than chlorine and since preventing algae growth needs chlorine anyway, this is why ozone should not be seen as necessary for sanitation. The main benefit of ozone is as an oxidizer and this is what SPP has seen. However, SWG pools also tend to be cleaner or clearer for somewhat similar reasons of greater oxidation of organics through continuous exposure of some of the water to high chlorine levels in the SWG cell. I would expect an ozonator to do better than an SWG in this regard, but both should be better than manual dosing though the difference is in the realm of subtle diminishing returns. The choice of filter and better circulation can make a bigger difference in water clarity (i.e. DE filter or sand filter with DE added vs. sand alone).
Richard
For concentration, you figure 1 gram per hour and divide this (1000 mg) by the number of liters flowing through the ozonator per hour. Using the 8 hour turnover time for the 8500 gallons, this is 4022 liters per hour. So that's 1000mg/4022L = 0.25 ppm. If the contact time is only 8.3 seconds as you've indicated, then this is a CT (concentration in ppm times time in minutes) value of 0.25 * 8.3/60 = 0.035 which is enough to give 99% kill rates for most bacteria and viruses, but not the protozoan cysts (Giardia and Cryptosporidium).
Higher levels of ozone can of course be used, but the above calculation is why UV is preferred as a method to inactivate the protozoan cysts. However, unless your pool is used by a lot of different people and these people swim when sick and have fecal accidents without telling you (or you noticing), I wouldn't worry about it.
Since ozone (at the concentration and contact time noted above) isn't any better than chlorine and since preventing algae growth needs chlorine anyway, this is why ozone should not be seen as necessary for sanitation. The main benefit of ozone is as an oxidizer and this is what SPP has seen. However, SWG pools also tend to be cleaner or clearer for somewhat similar reasons of greater oxidation of organics through continuous exposure of some of the water to high chlorine levels in the SWG cell. I would expect an ozonator to do better than an SWG in this regard, but both should be better than manual dosing though the difference is in the realm of subtle diminishing returns. The choice of filter and better circulation can make a bigger difference in water clarity (i.e. DE filter or sand filter with DE added vs. sand alone).
Richard
Richard,
Thanks for the correction on the PPM part, I forgot to add PER LITER title... and gracias for the CT correction.... 
Thanks for the correction on the PPM part, I forgot to add PER LITER title...
and gracias for the CT correction.... Re: Any one who has an ozonator and SWG?
Thank you all for the detailed info and calculations. The PB installed the ozonator today, it only took about 30 minutes. I can see the cloudy water, due to the ozone gas, at the venturi side, and the water already becomes quite clear by the time it gets to the return port which is 8 feet away. Now I am looking into getting the optional degasser column, since there is a waterfall at our pool, and the air bubbles are affecting the water flow. From the picture, the degasser column looks very simple, basically it is a PVC pipe, the bubbling water enters near the top so the gas can escape through the top vent and the water is drawn away at the bottom of the pipe free of gas, the description says it can remove 99% of the gas before the water is returned into the pool.
Thank you all for the detailed info and calculations. The PB installed the ozonator today, it only took about 30 minutes. I can see the cloudy water, due to the ozone gas, at the venturi side, and the water already becomes quite clear by the time it gets to the return port which is 8 feet away. Now I am looking into getting the optional degasser column, since there is a waterfall at our pool, and the air bubbles are affecting the water flow. From the picture, the degasser column looks very simple, basically it is a PVC pipe, the bubbling water enters near the top so the gas can escape through the top vent and the water is drawn away at the bottom of the pipe free of gas, the description says it can remove 99% of the gas before the water is returned into the pool.
I emailed Prozone today, got a reply regarding the degasser column, will be ordering one tomorrow. Meanwhile, I unplugged the Ozonator, plugged the air intake hose to the venturi, the waterfall is working fine.
I finally installed the degasser column and I turned the ozonator back on. Now I don't get bubbles at the waterfall. But after about 24 hours, the pool is a bit cloudy, according to Prozone's website, the water will become clear in a fill days. I just don't understand where the cloudiness is from? Assuming the ozone gas changes to oxygen quickly.
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