Is there any negative effect of both ozone and UV on the same tank ?

[kevensquint]

Hello, I have a very large tank being set up and it's deep from front to back so water clarity is a must. I have a Ozone generator on hand as well as a UV sterilizer from another tank. I was wondering if both plumbed into my sump could cause some type of bad interaction for the inhabitants? Thank you

 

[livinlifeinBKK]

Hello, I have a very large tank being set up and it's deep from front to back so water clarity is a must. I have a Ozone generator on hand as well as a UV sterilizer from another tank. I was wondering if both plumbed into my sump could cause some type of bad interaction for the inhabitants? Thank you

I cant say whether or not there will be any dangerous interactions but it seems like overkill...one negative to using both is that the water is going to be practically devoid of bacteria and any other microorganisms that would naturally be found in an aquarium. I'd personally say thats negative. Why not try one withput the other first? Honestly, just running activated carbon is enough to ensure clarity in most tanks.

 

[Randy Holmes-Farley]

There are pros and cons to each, but I don’t believe there is any detriment to using both together.

 

[Randy Holmes-Farley]

I cant say whether or not there will be any dangerous interactions but it seems like overkill...one negative to using both is that the water is going to be practically devoid of bacteria and any other microorganisms that would naturally be found in an aquarium. I'd personally say thats negative. Why not try one withput the other first? Honestly, just running activated carbon is enough to ensure clarity in most tanks.

Most people’s use of ozone does not sterilize the water being treated. The concentrations are too low with too short of a contact time.

 

[livinlifeinBKK]

Most people’s use of ozone does not sterilize the water being treated. The concentrations are too low with too short of a contact time.

Wouldnt you expect the combination to essentially sterilize the tank though? Wouldn't reproduction be heavily inhibited taking into consideration it's a new tank?

 

[Randy Holmes-Farley]

Wouldnt you expect the combination to essentially sterilize the tank though? Wouldn't reproduction be heavily inhibited taking into consideration it's a new tank?

The uv sterilizes water passing through it and is the reason I never used one. Ozone does not appear to have similar effects. I discuss that issue and more here:

Ozone and the Reef Aquarium, Part 1: Chemistry and Biochemistry by Randy Holmes-Farley - Reefkeeping.com

Ozone and the Reef Aquarium, Part 2: Equipment and Safety by Randy Holmes-Farley - Reefkeeping.com

Ozone and the Reef Aquarium, Part 3: Changes in a Reef Aquarium upon Initiating Ozone by Randy Holmes-Farley - Reefkeeping.com

From the first one:

Reducing Bacteria When Using Ozone

---

Bacteria and other organisms suspended in water can be killed by adequate exposure to ozone. That process is widely used to disinfect drinking water and wastewater in a variety of applications. The doses and exposures of ozone required for disinfection, however, are quite high. They are higher than are used in reef aquarium applications, where typical doses of ozone range up to about 0.3 ppm in typical contact chambers, and last for only a few seconds. Consequently, aquarists must be careful when translating disinfection literature to reef aquarium effects.

In a recent study of a recirculating seawater system,35 the dosing of 0.52 ppm of ozone was tested for its ability to decrease the system's bacterial load. That dose is similar to a 300 mg/hr ozone unit applied to a typical small skimmer flow rate of 150 gallons per hour (568 L/h). In this experiment, the levels of suspended bacteria (both Vibrio and coliform) were analyzed in a variety of locations (intake, pre-ozone, post-ozone, pre-tank, and post-tank). In no case was there a statistically significant reduction in bacteria. Even the addition of a venturi injector to the contact chamber did not adequately help (although it trended toward fewer bacteria, the result was not statistically significant). For comparison purposes, at higher ozone concentrations and contact times (5.3 ppm ozone for 240 minutes), Vibrio vulnificus is easily killed, with fewer than one in a hundred million of the initial bacteria remaining.36

How much ozone, and for how long, is required to kill suspended organisms in seawater? In one study of a suspended dinoflagellate algae (Amphidinium sp. isolated from Australia's Great Barrier Reef), it was found that 5-11 ppm ozone for six hours of exposure was required to kill 99.99% of the organisms.37 While that kill rate is impressive, that exposure is far higher than is ever achieved in a reef aquarium application. Lower doses and shorter contact times had smaller effects. A dose of 2 ppm and a short contact time (with the time not stated in the paper) showed a reduction in bacteria of abut 98% (which is still quite significant, but would not be referred to as disinfection).

Similar results were found for the spores of the bacterium Bacillus subtilis.38 In this case, doses of 14 ppm ozone for 24 hours were required to kill 99.99 percent of the spores. In another study 99.9% of fecal coliforms, fecal streptococci and total coliforms were killed with 10 ppm ozone and a contact time of 10 minutes.39 The exposure of Vibrio species and Fusarium solani (bacteria that are pathogenic to shrimp) to 3 ppm ozone for five minutes killed 99.9% of the bacteria.40Water from a seawater swimming pool was effectively sterilized using 0.5-1.0 ppm ozone in a contact tower.41

The data for the disinfection of freshwater systems are much more extensive, and so include more data at lower contact times and concentrations. In one experiment at a Rainbow trout hatchery, the addition of 1-1.3 ppm of ozone with a contact time of 35 seconds reduced heterotrophic bacteria in the aquarium water itself by about 40-90%.42

Does the ozone used in a typical reef aquarium application reduce bacteria? Maybe, but certainly not to the extent required for disinfection. Still, a reduction of 50% of the living bacteria could have significant effects. The above study in the trout hatchery showed that the use of ozone at several times the typical reef aquarium rate and for about five to ten times the typical contact time results in such a drop. While the data are unavailable, I expect that the bacteria in the water exiting a normal reef aquarium's ozone application are not decreased by as much as 50%.

It seem reasonable to conclude from such literature studies that most bacteria that enter the ozone reaction chamber in a typical reef aquarium application will not be killed by ozone or its byproducts. If killing bacteria in the water column is a goal, then a UV (ultraviolet) sterilizer may be more useful.

 

[kevensquint]

Thank you for the responses. !

 

[livinlifeinBKK]

The uv sterilizes water passing through it and is the reason I never used one. Ozone does not appear to have similar effects. I discuss that issue and more here:

Ozone and the Reef Aquarium, Part 1: Chemistry and Biochemistry by Randy Holmes-Farley - Reefkeeping.com

Ozone and the Reef Aquarium, Part 2: Equipment and Safety by Randy Holmes-Farley - Reefkeeping.com

Ozone and the Reef Aquarium, Part 3: Changes in a Reef Aquarium upon Initiating Ozone by Randy Holmes-Farley - Reefkeeping.com

From the first one:

Reducing Bacteria When Using Ozone

---

Bacteria and other organisms suspended in water can be killed by adequate exposure to ozone. That process is widely used to disinfect drinking water and wastewater in a variety of applications. The doses and exposures of ozone required for disinfection, however, are quite high. They are higher than are used in reef aquarium applications, where typical doses of ozone range up to about 0.3 ppm in typical contact chambers, and last for only a few seconds. Consequently, aquarists must be careful when translating disinfection literature to reef aquarium effects.

In a recent study of a recirculating seawater system,35 the dosing of 0.52 ppm of ozone was tested for its ability to decrease the system's bacterial load. That dose is similar to a 300 mg/hr ozone unit applied to a typical small skimmer flow rate of 150 gallons per hour (568 L/h). In this experiment, the levels of suspended bacteria (both Vibrio and coliform) were analyzed in a variety of locations (intake, pre-ozone, post-ozone, pre-tank, and post-tank). In no case was there a statistically significant reduction in bacteria. Even the addition of a venturi injector to the contact chamber did not adequately help (although it trended toward fewer bacteria, the result was not statistically significant). For comparison purposes, at higher ozone concentrations and contact times (5.3 ppm ozone for 240 minutes), Vibrio vulnificus is easily killed, with fewer than one in a hundred million of the initial bacteria remaining.36

How much ozone, and for how long, is required to kill suspended organisms in seawater? In one study of a suspended dinoflagellate algae (Amphidinium sp. isolated from Australia's Great Barrier Reef), it was found that 5-11 ppm ozone for six hours of exposure was required to kill 99.99% of the organisms.37 While that kill rate is impressive, that exposure is far higher than is ever achieved in a reef aquarium application. Lower doses and shorter contact times had smaller effects. A dose of 2 ppm and a short contact time (with the time not stated in the paper) showed a reduction in bacteria of abut 98% (which is still quite significant, but would not be referred to as disinfection).

Similar results were found for the spores of the bacterium Bacillus subtilis.38 In this case, doses of 14 ppm ozone for 24 hours were required to kill 99.99 percent of the spores. In another study 99.9% of fecal coliforms, fecal streptococci and total coliforms were killed with 10 ppm ozone and a contact time of 10 minutes.39 The exposure of Vibrio species and Fusarium solani (bacteria that are pathogenic to shrimp) to 3 ppm ozone for five minutes killed 99.9% of the bacteria.40Water from a seawater swimming pool was effectively sterilized using 0.5-1.0 ppm ozone in a contact tower.41

The data for the disinfection of freshwater systems are much more extensive, and so include more data at lower contact times and concentrations. In one experiment at a Rainbow trout hatchery, the addition of 1-1.3 ppm of ozone with a contact time of 35 seconds reduced heterotrophic bacteria in the aquarium water itself by about 40-90%.42

Does the ozone used in a typical reef aquarium application reduce bacteria? Maybe, but certainly not to the extent required for disinfection. Still, a reduction of 50% of the living bacteria could have significant effects. The above study in the trout hatchery showed that the use of ozone at several times the typical reef aquarium rate and for about five to ten times the typical contact time results in such a drop. While the data are unavailable, I expect that the bacteria in the water exiting a normal reef aquarium's ozone application are not decreased by as much as 50%.

It seem reasonable to conclude from such literature studies that most bacteria that enter the ozone reaction chamber in a typical reef aquarium application will not be killed by ozone or its byproducts. If killing bacteria in the water column is a goal, then a UV (ultraviolet) sterilizer may be more useful.

I wasnt aware the doses were so small! I just know from what Ive read that the combination of ozone and UV leads to the formation of hydroxyl radicals which are highly reactive. It's all dose-dependent though like you said so it would be necessary to take each variable into consideration in order to determine the combined effects.

 

[Doctorgori]

Your water will be clearer and warmer that’s for dang sure…
Regardless I have at least one or the other or both hooked up on all 3 of my tanks and whether they are on or off is dependent on temp, clarity or disease presence
… nothing wrong with hooking up both and operating one, both or neither
Added: if you aren’t set on the brand be sure to check out the annual maintenance cost and parts availability for your UV unit .. it can be a PITA

 

[taricha]

One consideration is that if using ORP to regulate the Ozone dosage, some users have found that turning on UV lowered the ORP, which mostly makes sense if it is destroying Ozone, and my understanding is that is theoretically what should happen to ozone entering UV.

 

[Doctorgori]

One consideration is that if using ORP to regulate the Ozone dosage, some users have found that turning on UV lowered the ORP, which mostly makes sense if it is destroying Ozone, and my understanding is that is theoretically what should happen to ozone entering UV.

Wasn’t there some discussion/thread somewhere on the installation order? (UV then Ozone) or does it even matter given the variables of contact time, flow rate, volume, turnover et

 

[Randy Holmes-Farley]

Wasn’t there some discussion/thread somewhere on the installation order? (UV then Ozone) or does it even matter given the variables of contact time, flow rate, volume, turnover et

Hopefully, users remove the ozone and its toxic byproducts with GAC, so that the uv is not hitting on the ozone anyway.