Backyard Aquaponics
A place to discuss aquaponics

Uh, hold on there Dan. A few fun facts about Ozone use in aquaculture/aquariums first.

Ozone is used in Marine applications far and away more than it is in freshwater, though it can be used in freshwater if done properly.

Ozone should be applied at the equivalent of 5 to15 mg/hour per 100 litres of volume (typically via venturi injection). In commercial applications 0.05mg ozone per litre of flow is sufficient to achieve a recommended redox of 300 to 400 mV. A much higher dose rate of 0.2 to 0.5 mg of ozone per litre of flow is required to achieve redox levels of 700-800 mV, at which the water can be considered sterilised, but unfit for aquaria usage without ozone infused water being run through a carbon chamber and/or a UV sterilizer to convert the excess O³ into CO² ( which you will have to supplant with additional aeration and buffer since CO2 dissoved in water forms carbonic acid and lowers the pH of your system). And this notion of the water "having a lot more free oxygen" is patently false and misleading to others.

After 24 to 48 hours of ozone usage, the dirty water in the aquarium will seem to "disappear" as the small particles and coloured materials are removed from the water. The clarity of the water is quite simply unequalled by any other system- BUT...

UV is miles safer and cheaper than O3. O3 will KILL your fish if you make even the slightest error. Unfortunately, this has happened on a large and public scale in several aquariums.
http://www.theindychannel.com/news/1852 ... ail.html#-

And if you aren't real careful, it can kill you too, seriously- this is not a joke, you can kill yourself and your loved ones with ozone, especally in an enclosed area- like a greenhouse or pavillion:
http://www.medicalnewstoday.com/articles/105014.php

At levels above 2ppm, ozone is very irritating and can be injurious to humans, causing chronic respiratory disease and pulmonary oedema, which can be fatal.

The solubility of ozone is very limited and excess ozone does not remain in the water, but is released to the air as a gas

After you sterilize with O3, you must de-gas adequately or you will kill your fish (i.e degassing towers or carbon or UV). Plus, O3 is a super powerful oxidizer and will destroy plumbing, etc if you don't use the right materials. And because Ozone dissolves solids and oganics, you MUST use a protien skimmer to remove the waste or your entire system gets really nasty in a big hurry. Additionally, O3 is not good for you to breathe or for the environment, and de-gassing means the O3 leaves the water and enters your environment. After years of chronic headaches and nosebleed from being around O3 generators and degassing columns, I'll pass, thx.

The ignorant skepticism and rampant paranoia about UV and it's effectiveness/usefulness I find here is almost laughable. This technology is time tested and proven. If you've ever consumed municipal tap water anywhere other than (and sometimes including) the third world, or bought bottled water or virtually ANY fruit juice, or popular carbonated beverage (often including beer), the source water has almost certainly been UV treated. Why? because it is the most effective and cost efficient means of sterilizing free-floating microbes (and depending on kill rate of the bulb, this includes parasites such as gut worms, and other waterborne parasites.)

It seems everyone here has an internet connection, so I'm not apt to do a lot more homework to convince you; but if nearly every fish hatchery (of any size) you can find employs this technology, perhaps that is a good indication as to the usefulness of this technology.

Just have a look at the web pages for any of the manfacturers of this stuff, like Emperor, AquaUltraviolet, or Trojan UV, etc. you will find kill rates and more testamonial than you care to read.

Seriously.... the need for such methods in a balanced aquaponics system with reasonable stocking rates.... and media filled growbeds...

Just doesn't justify the expense, effort and results IMO....

Interesting info about ozone FR, thanks!

I don't think anyone is doubting the effectiveness of UV in sterilizing the water, or its safety. The objection is to suggest that AP systems need to have UV lamps added to them. When a newbie is figuring out how to set up a new system a UV lamp should be way down the list. You are biased because you already have the equipment, as shown in your system pictures. The average user should spend their dough on maximizing volume first of gravel beds and then of water volume; and once this is done the need for sterilizing pathogens will be very small, assuming they are careful about new fish sources and procedures for adding them. How much did your UV setup in your aquarium system cost???

RE: UV cost, I know it was given to you for free, but how much would it cost to buy new?

Proper filtration, aeration... good feed practices... good stock, and good stocking rates... should mean that pathogens shouldn't be a problem...

http://www.aquaticeco.com/subcategories ... h%20talk/0






OK Rupert, anyone who has read your contributions to this thread knows how you feel. You're beginning to sound like a broken record.





I agree that a UV unit should be a ways down the list, but not at the bottom. It seems that the tendency on this forum is to assume that everyone is doing their AP in media (mine is aeroponic), or that everyone has the space to do all of this maximizing of water volume and grow bed media. The Emperor UV's I have are ~$275US each. But are by no means the right units for everyone.

UV units can be had for $100US, but need to be spec'd for your individual needs.

And it seems that most everyone has the misconception that UV is used priimariy for algae/single celled organisms. Not true. I have included a link and the full text of AES Tech talk #96 which includes a chart of kill rates for a variety of microorganisms (including Ichthyopthyris (a.k.a. Ich), Tobacco mosaic virus, salmonella, fungi, E. coli, etc.) http://www.aquaticeco.com/pages/full_wi ... terilizers

Ultraviolet (UV) Sterilizers
Tech Talk 96
In order to protect aquatic livestock held in aquariums or holding tanks, biologically treated water should be adequately disinfected before returning it from the filter system. Mechanical and biological filtration does not provide inactivation of pathogenic bacteria, protozoa and viruses.

Ultraviolet radiation (germicidal) energy is unmatched in its efficiency, simplicity and dependability when applied as a microorganism disinfectant! It is most effective for its germicidal value in a clear water application at a wavelength of 265 nanometers. With proper exposure, ultraviolet radiation energy (ultraviolet light) penetrates a microorganism's cell wall. It then destroys the nuclear material, causing abrupt modification and quickly bringing about its destruction.

At AES we hear from a lot of people who have ultraviolet (UV) sterilizers and are still experiencing disease problems. This can almost always be traced back to inadequate UV irradiation. Because it is so difficult to measure the intensity of UV energy hitting the water, many buyers have improperly sized their UV sterilizers by simply following the maximum gpm flow rate published for 15,000 µWs/cm²* (who said aquaculture was easy?).

This is the problem! You cannot compare UV sterilizers by the watt ratings alone. That would be like comparing cars by their engine size alone. The watt rating is just the starting point for comparisons.

The full amount of UV energy required to kill a microorganism must hit the organism after the energy leaves the lamp, after it leaves the quartz sleeve, after the lamp has aged and after it has passed by any turbidity and color that block the light.

Low-pressure mercury type UV lamps are best suited to germicidal action because the primary radiation generated by these lamps consists almost exclusively of a spectral wavelength of 254 nanometers, which is close to the maximum peak germicidal effectiveness wavelength of 265 nanometers. This gives the low-pressure mercury type lamps an exceptional 40 percent UV energy efficiency rate between input watts and UV output watts.

Medium- and high-pressure mercury type lamps are best suited for treatments involving chemical by-products associated with industrial waste water or for the drying of printing inks, paints and adhesives, not germicidal action.

The bulk of their power is in the 320 to 440 nanometer range, well outside the germicidal range.

Ultraviolet light can be very effective at eliminating viruses, bacteria, algae and fungi. The required UV exposure rate to irradiate common bacteria is 15,000 µWs/cm² , while the required UV exposure for waterborne algae is 22,000 µWs/cm² . Since it is the intensity of light that is doing the killing, we must know how much light energy to use and how much is reaching the target. Just as some sunglasses and sunscreens reduce UV intensity, so do discolored water, turbidity, dirty quartz sleeves and even some dissolved salts, such as sodium thiosulfate. Lamp temperatures may even reduce output when operated in cold water (110°F gives maximum UV output).

To ensure sterile water using UV light, first start with clear water, and have a lamp and flow rate that are sized to deliver the correct amount of irradiation for the target organism (see exposures list). If a UV light is flow rated for 15,000 µWs/cm² and you want 30,000, either double the number of lamps or reduce the flow by half, and so on for higher dosages.

Be aware that some lamps age rapidly, and the manufacturer probably states the watts produced when the lamp is new. This wattage can be reduced by as much as 40 percent in as few as six months! We suggest oversizing the UV sterilizer by at least 40 percent to be sure of getting the killing power required when the lamp has aged. We also suggest changing lamps at six-month intervals. For a more in-depth look at UV sterilization and system design, consult the book Aquaculture Engineering (WQB3).

*µWs/cm² = exposure to ultraviolet light of 253.7 nm wavelength in microwattseconds per square centimeter.

UV Exposures

Great information FW,.... and I didn't intend anything personal in my posts...

Pre-filtering of solids and/or UV, ozone treatment has it's place in a aquaria systems, and some aquaculture systems, (particularly to treat source water)....

And is a must (pre-filtering) for NFT & DWC applications and particularly aeroponics as you are applying it...

I was merely attempting to stay on topic... "Ultra Violet Filtration-has anyone used it in aquaponics"....

And as you say I have expressed my views accordingly with regard to use/cost of such things... and their benefit, if any, in flood and drain aquaponics.... particularly in relation to anyone starting out/designing a new system....

FishWrangler

I had understood that even at less than lethal dose it can still effect the organism detrimentally. Just wondered if you had heard or read anything on this?

I have not heard such claims but it would stand to reason. Any exposure to UV could have a deleterious effect on a microorganisms biology/physiology and even to it's DNA- causing mutations that could potentially lead to an inability to reproduce or sporulate, locomote or even live for much longer. I don't think that there is a better way to spend $100-200, especally if you plan to push the limits of stocking density - or for that matter, any of the other normal-range environmental parameters for your fish. And afterall, many of us would love to increase our stocking density, right? I mean, more fish = more nutrients for plants and more food produced, and that's the whole idea here, right?

So, if you intend to push the limits of your stocking density, some of the base requirements to do so would include increased DO (e.g.oxygen injection), and increased/improved filtration (biological and mechanical, and even UV), right? And more crowded fish, means a higher baseline stress level, which increases the chances of a pathogen getting a real foothold in your fish stock (make no mistake, these pathogens are already present in many systems- just like the cold virus, and countless other human pathogens in our envirinment); but if your fish are healthy and not too stressed to begin with, they are mostly unaffected (save for the weak ones). UV is just another layer of protection you have which can make a valuable and significant cotribution to ANY aquaria/aquaculture system. I mean, many of us think nothing of throwing a couple of hundred dollars at fingerlings and fish food and water treatments and plumbing. I feel that UV is well worth the investment, especially if it means I can increase the number of fish in a system- and combined with the other improvements I mentioned, it does mean just that.

I hear you FW... yes pathogens are constantly present in systems... and are opportunistic by nature, striking when fish are stressed.

Water quality parameters are the number one stress factor leading to disease... and adequate filtration, plus a reserve.. is essential for good fish health.

Especially if anyone is going to push their stocking densities to the limit...

"To the limit" though implies.... with little margin for error.... and on the limit of your filtration and/or your DO capacity....

ie... that you are beginning to place your fish under stress and provide an opportunistic environment for pathogens and disease...

UV might buy your some breathing space.... but it's not a practise I would recommend for the sake of "pushing the limit"... and good fish health...

Better IMO to maintain safe stocking limits and adequate filtration.... good water quality management... means good fish health....

Somewhat a rhetorical question.... but given the nature of most backyard AP systems... is it worth the risk of fish disease... or mortalities.... to squeeze a fish extra fish/L of water???

I find this rather curious as the wealthy and those who are lucky in numbers are the only ones who'll ever consider a investment such as this.

Save for those few who are reading and asking questions on commercial scales, we're talking about family sized systems, right?

Why the need to use this UV to protect fish when most of us are not overstocking our systems - save those who didn't know they were doing it?!

Then there's this kind of adage I'm hearing a lot about... you gotta challenge the fish's nervous system every now and again so that they can keep living healthy, by changing their environment once in a while.
It seems more appropriate to get the fish to develop natural immunity than to waste 200 or more bucks on UV!

At the risk of sounding naive, I also still don't know anyone who has declared that they live entirely on fish as their base diet, have you?

Jen

I am neither wealthy or lucky in numbers (whatever that means). I do not overstock or even eat my fish (goldies). I would not run UV fulltime, however if I could improve water quality I would on a regular basis run a uv (and have occasionally).
If you could improve the quality of the air you breathe would you do so? Or do you accept that occasionally a bit of pollution is good for the system.
I smoke so I have made my choices, but the fish are in my care so I try to avoid HSM.

BTW I would have thought fish and vegtables would be a fairly healthy diet.

Few million Asians and Polynesians who would tend to agree with you Sleepe...