Ozone with UV

[jjk_reef00]

I don't know if this is advanced but I cannot get any answers in the equiptment forum so I'm hoping someone can answer me here...

Does anyone use both?
Can this be done?
Every post I read it is about someone changing from UV to Ozone or vice versa.
I have never read anyone using both?

I have a UV, and I'm thinking about adding ozone also.
Anything I have to watch out for if I want to run both?

Can I run the output of my uv directly into the ozone reactor?

 

[108reefer]

You can run both - essentially they do the same thing. the ozone generator is more efficient than the light (generally speaking). you are trying to get a higher ORP reading, if your not sure what this is - please do some homework on it. search for "ozone" in the search engine here and you will get some great info about using ozone. see what your ORP reading is now, then you can determine if you need more. you probably wont need the light when you start a reactor. hope this helps!

 

[wooden_reefer]

Ozone does more than disinfect; but also oxidizes and affects water chemical quality.

UV does not affect water chemical quality materially.

Ozone is much more expensive to own and operate.

 

[KarlBob]

I'm not sure what you mean by "materially", but UV can change water chemistry by a measurable amount. Reactions between UV light and chemicals in the water generate small amounts of ozone. Directly adding ozone usually changes Oxidation/Reduction Potential (ORP) more than UV does, because most UV systems only generate a small amount of ozone.

UV and ozone disinfect somewhat differently. UV disinfection involves a chemical process and a photochemical process. Ozone leaves out the photochemistry.

Ultraviolet light at the correct frequencies damages DNA. Bacteria with damaged DNA may survive for a little while, but they generally can't reproduce. As mentioned earlier, UV also generates small amounts of ozone and other free radicals.

As shown here, ozone disinfects by oxidizing various components of bacterial cells, including their cell walls. Destruction of the cell wall, called lysis, destroys the bacterial cell. It's a much more direct killing mechanism than sterilizing bacteria by messing up their DNA.

 

[wooden_reefer]

Are you sure that UV can generate much ozone from O2 dissolved in water?

Is ozone generated by UV mostly from gaseous oxygen?

Yes it does some, that is why I said materially, for this reason.

 

[KarlBob]

Ok, I'll grant that UV affects water chemistry much less than direct ozone addition, but UV does have a noticeable effect.

Yes, UV light generates O3 from dissolved O2. UV light at 185 nm splits O2 into 2 monatomic oxygen atoms. The separated oxygen atoms hook up with the nearest O2 molecule to form O3.

Note: UV light at 254 nm messes with DNA. Most UV disinfection lamps aim for this frequency, and produce far less light at 185 nm.

 

[H20ENG]

Good info above.
So the OP doesnt get confused,
Most UV sterilizers are the 254nm lampsin a quartz glass (lets that frequency of light through)sleeve which water flows around to be disenfected.

Ozone generators are generally of 2 types:
Either corona discharge high voltage with a dielectric cracks the O2 molecules to recombine as O3 (as stated above).
Or a 185nm UV lamp is used, but with no sleeve and air is flowed across the lamp.

Both types of O3 generators crack the O2s and recombine to form O3.

Ozone needs much higher doses to disenfect the water as well as UV can, and the excess must be absorbed or destroyed by carbon or more UV (I forget which wavelength they use for destruct).

BUT IMO, ozone is more effective in the overall health of the tank, as described above in helping with oxidation and tank clarity. Use an ORP monitor if you use ozone to keep it below 450mV.

 

[tmz]

Nice post H2O

 

[wooden_reefer]

<a href=showthread.php?s=&postid=15263719#post15263719 target=_blank>Originally posted</a> by H20ENG
Good info above.
So the OP doesnt get confused,
Most UV sterilizers are the 254nm lampsin a quartz glass (lets that frequency of light through)sleeve which water flows around to be disenfected.

Ozone generators are generally of 2 types:
Either corona discharge high voltage with a dielectric cracks the O2 molecules to recombine as O3 (as stated above).
Or a 185nm UV lamp is used, but with no sleeve and air is flowed across the lamp.

Both types of O3 generators crack the O2s and recombine to form O3.

Ozone needs much higher doses to disenfect the water as well as UV can, and the excess must be absorbed or destroyed by carbon or more UV (I forget which wavelength they use for destruct).

BUT IMO, ozone is more effective in the overall health of the tank, as described above in helping with oxidation and tank clarity. Use an ORP monitor if you use ozone to keep it below 450mV.

Yes, I think probably so, but O3 is more expensive to own and operate. Excessive UV seldom does any harm, O3 is different.

Does the control mechanism for O3 fail often?

 

[H20ENG]

I dont think O3 is more expensive to own and operate really. Even with a controller, its probably about the same.

UV are high first cost and high lamp replacement costs. Probably about the same time involved for maintenance, if not slightly more for the UV. It of course depends on specific models of UV or O3 generators, but on the hobby level probably close.

I do agree with the statement that "Excessive UV seldom does any harm, O3 is different." Too much ozone can do a lot of damage, not only from free ozone reacting directly (oxidation) with the animals, but also the formation of hypobromous acid if the levels get too high. Stay below 450mV and the tank will be fine.

Luckily ORP controllers tend to read higher ORPs when the probes are dirty, (counterintuitive for sure- you'd think that if the probe was dirty it would read low) and shut down the ozonator. Probes can be cleaned easily with a toothbrush and vinegar.

 

[H20ENG]

Definitely benefits of each, and no reason you couldnt run both.

When I use UV, I tend to run a high dosage to be sure its killing algae and parasites.

When I use ozone, I run a low dosage to help overall tank clarity and ORP.

A very slight dosage of ozone to the skimmer will help it produce the nastiest skimmate known to man (especially in an Pacifc Giant octopus (Octopus doleflini) tank!!!:hmm5: ) But too much will shut down a skimmer. The ozone oxidizes the waste before it can be collected in the skimmer.

HTH,
Chris

PS Thx tmz

 

[H20ENG]

Something I have seen in the HVAC industry but not yet in the pet industry is a combined use UV lamp. I drew up a prototype but never built one for water use.

Basically it is known that ozone is a very effective oxidizer and will help keep mold from growing in ductwork. But it is too easy to raise O3 levels beyond the acceptable PEL for humans in air.

UV only kills the mold where its radiation (light) can reach, so is not as effective in large ductwork runs.

So they make a common UV lamp by fusing 2 types of glass- one part is quartz, to let the 254nm light through for direct sterilization. The other glass (sorry cant remember its makeup) blocks the 254 but lets the 185 through producing ozone from some of the air around the lamp.

IIRC, the lengths of each type of glass work out to 75% 254, 25% 185 in order to keep the ozone levels below PEL, but still get oxidation and that wonderful clean fresh smell


Actually now I think about it, Emperor Aquatics has done something similar now. So much for breaking news, LOL

 

[wooden_reefer]

Is it inexpensive to change the arc? Does it have to be changed often?

What parts of the control have to be replaced periodically?

 

[H20ENG]

The latest and greatest technology now seems to be PCO, or photocatalytic oxidation.

This uses a UV lamp for sterilization, but also uses a grid or screen coated with titainium dioxide. The TiO2 reacts with the UV light (<350nM) giving off "free radicals and superoxides".

The word "ozone" is bad to air purification marketers, so they call it "free radicals and superoxides", LOL. But its an easy way to get a bit of ozone with your UV lamp.

And ozone simply works great, but people are scared of it. What do you think smoke restoration companies, hotels, & car detailers use to get rid of those smells? We have one on our trash compactor at work.

Magnavore just released a small reactor that uses a UV LED and a small patch of TiO2. The first PCO reactor for aquaria that I've seen.

PCO is all the rage in architecture now too. They are coating everything in TiO2 and touting it as self cleaning, or antimicrobial. The house that cleans itself! Funny 99% of TiO2 goes into household paint!! Its nothing new. Lots of HVAC filters and air purifiers coming out with PCO too.

 

[H20ENG]

Wooden,
If its a CD unit, it shouldnt need changing for ten years or more, depending on the usage and moisture content of the air that passes through it.

Air dryers help wring more ozone out of the air and help the CD cell last longer, but is not completely necessary for our use.

A new probe every couple years maybe.

Corona discharge units (usually) do not actually spark. They use high voltage (5kV and up) on an electrode with a dielectric (glass) between it and a ground electrode, with a very thin air gap between them. If the glass was not there the high voltage would jump to ground, but it cant. The high voltage excites the molecules passing by causing a corona (purple tinged light) to form. This is what cracks the O2s into O1s.

 

[KarlBob]

That's funny about the "free radicals and superoxides" terminology. I remember when you could still buy cans of O3 as air fresheners. Now it's so scary that companies apparently use euphemisms to avoid the public hearing its name. Hilarious.

 

[estamm]

Iv always wondered if its feasable to use a UV filter in place of carbon to break down the O3.??? Has anybody ever tried running their skimmer output through a UV unit before it goes into the sump or tank???.The idea is based on the assumption that ozone can be broken down with a UV unit.... Iv heard that said before but never really looked into it... An inline UV barrier could be a cool addition to an ozone setup if in fact it could be used to break down the ozone....Im too chicken to let my automated ozone setup run without me being there to observe it even though I run the output through a carbon sock, as anybody who has used ozone knows it is really easy to over-do it....

 

[MrPike]

Do you have any o3 units you recommend H20ENG?

I have experience with the Ebay units(enaly) and they last for about a year before they stop working due to corrosion. If I had a proper air dryer they would probably last a lot longer.

Most hobby units like red sea seem to be overpriced junk, and I don't believe you can take them apart for servicing if needed.

 

[H20ENG]

Unfortunately, most hobby units that I have used cannot be taken apart for cleaning We use large ozone generators at work for the big tanks and system water that we could disassemble and clean.

I have seen some UV based ozonators that could be cleaned, as well as a very small coralife unit that simply used some wire mesh inside a small glass vial

I like the red sea units as all in ones, except that you cant get them apart!

 

[H20ENG]

Driers are a love hate relationship. You need to bake the dessicant to get the moisture out, and its a time consuming proccess.

Better if you have several pounds of it that you can keep dry and do several media changes before having to dry it all again. Use a vapor tight container to keep it in. And try not to draw the air from the humid fishroom but from in the driest part of the house, or outside if its a cold dry climate.

Also what happens in the generators is the ozone reacts with the nitrogen in the air, creating nitric acid, which will even eat stainless steel. This, along with the salt in the air of our fishrooms causes corrosion in the units.

In commercial units, they use oxygen concentrators, removing nitrogen and moisture. The PSA (Pressure Swing Absorption) concentrators lower the dewpoint very low, thus a win/ win for the ozonator. (Same machines used for breathing aids, and why those have humidifiers built in) This slows corrosion and makes more ozone from the machine than just air.

I havent looked into the RK2 units or Ozotech. I imagine that for the cost of those, you can clean them.