No worries, you're welcome. I am still gearing up for my first grow, so not using ANYTHING at the moment.....unfortunately.........but I am just like you, nothing but the best and buy once.........reading a lot and keep changing my mind about what is the "best".......hahaha.......thanks to this great forum it makes decisions easier, although there is a steep language learning curve to negotiate.......acronyms, abbreviations and expressions only the initiated understand in galore here.....is there somewhere on the forum a dictionary where the most common terms and such is translated into plain english.......I mean, bennies, WTF.......took a little googling to figure that one out......amongst many others.......:no:
Regarding UV sterilizers.......the one you linked to......I wouldn't touch it with a very long barge pole. The thing with these "sterilizers" is that most of them are actually just clarifiers, i.e. they will kill off algae in ponds and such, so the water remains clear. The one you linked to does not even mention anything about flow rate, which is critical(exposure/dwell time). To kill algae, an exposure of 30 mJ/cm2 is minimum, to kill protozoa(what you are after) 180 mJ/cm2 is minimum, and that means a very slow flow rate. You have, what, some 1000 liters or there abouts in your system, and to get an effective turnover rate of say 1 hour, you need a sterilizer which can deliver 180 mJ/cm2 to a flow of app. 16 LPM(liters per minute). Dunno how you plan to integrate/hook it up, in a separate loop or directly in the existing pipes?.........what flow rate, or turnover are you aiming for in your system....... there is the fact that the lamp(s) and the quartz sleeve has to be changed every year or so........a monitor/controller is highly recommended.......and that ain't cheap.......plus the power consumption.....let alone the sterilizer itself, and you are talking in the kilo's for a years worth. There is no way that a cheap china UV clarifier will frighten any unwelcome critters in your water......and to call a clarifier a sterilizer is rather cheeky by the marketing blokes, perhaps they had been smoking something:slaps: when they dreamed that one up........although I suppose in you ran 0.1 LPM through it they critters might raise an eyebrow for a little while......
Have a look here for more info and to give you an idea 
http://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation#Effectiveness  http://www.emperoraquatics.com/basic-uv-controller.php and 
http://www.emperoraquatics.com/smart-ho-uv-sterilizers.php randomly chosen amongst many reputable manufactures.......again, it is expensive gear!
From Wikipedia 
Sterilization is often misquoted as being achievable. While it is theoretically possible in a controlled environment, it is very difficult to prove and the term "disinfection" is used by companies offering this service as to avoid legal reprimand. Specialist companies will often advertise a certain log reduction e.g., 99.9999% effective, instead of sterilization. This takes into consideration a phenomenon known as light and dark repair (photoreactivation and base excision repair, respectively) in which the DNA in the bacterium will fix itself after being damaged by UV light.
Aquarium and pond sterilizers are typically small, with fittings for tubing that allows the water to flow through the sterilizer on its way from a separate external filter or water pump. Within the sterilizer, water flows as close as possible to the ultraviolet light source. Water pre-filtration is critical as water turbidity lowers UVC penetration. Many of the better UV sterilizers have long dwell times and limit the space between the UVC source and the inside wall of the UV sterilizer device.
Corgy