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
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And this, table 2
http://???.ozoneapplications.com/info/disinfection.htm
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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
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Hope you get the ozone benefit the way I do.
Cheers