I have used most every type of UV Sterilizer & Clarifier over the years, including; the Nektonics UG Filter UV, the Lifeguard, Aqua UV, Emperor UV, Terminator UV, Aqua Top UV, TMC UVs, Tetra UVs, and the list goes on!! Strohmeyer; Aquarium Keeping Bio See these articles about the use of medium pressure versus the better but more expensive low pressure UV Bulb: *UV (UVC) Lamps (Bulbs) used in Aquariums and Ponds and how they work *Actual UV-C Emission from a UV Bulb; Aquarium or Pond These low end UVs often have very limited life times due to design, such as ballasts/transformers that last as little as 8 months.
The UVs I promote cover different niches from lower end to higher end.
Since photons are subatomic particles with mass, they can disturb chemical bonds, from bumping an electron off a molecule (Visible) to breaking apart molecular bonds (UVC), to modifying the makeup of each atom directly (Gamma Rays).
All photons have a "Chance" to do any of the above, but the higher energy events are far more likely to happen with a high energy/high frequency photon interaction over a longer wavelength/visible spectrum photon.
Infrared light is wavelengths over 1000nm, while UVA is around 400nm, and UVC is around 250nm.
That covers the visible spectrum and immediate neighbors, all the colors are between about 450 (blue)-700nm (deep red to near IR).
Also for general water quality control such as Green Ponds or Cloudy Aquariums.
As well the use of UVC Sterilization is useful in home, office, hospital air purification & even UVC/Redox Blood therapy.
UVC is better at breaking molecular bonds as well as rearranging electron configurations, this is how UVC sterilizes, and why Dwell Time is important.Near the limits, at X-Ray to Gamma Ray Sources are used medically to "disrupt" cancerous tumors, with the same interactions mentioned in this post, but at far, far higher energies.Ultra violet sterilization is an effective tool especially when combined with other tools such as new fish quarantine (or new fish baths) for disease prevention in aquariums, ponds.I also have read much research, including research outside the often anecdotal aquarium keeping hobby, which often explained results I was getting in some experiments in the 1990s that explained the role in Redox and UVC and how True UV Sterilizers can lower oxidative stress.One way I measured results in testing specific UV devices was to use a murky slurry of water with bacteria grown from decomposing fish food and back yard dirt, and then time how long certain UV devices would clear the the aquarium this was added too.UVA and UVB that can reach the Earths surface are primarily non-ionizing and do not have enough energy to ionize atoms.