Advice needed for UV/UV-C

[Barracuda]

Hi all, thinking of getting a UV sterilizer in my tank to get rid of algae/parasites/other bad stuff (like white spot). I dont know much about it so i need some advice :)

First of all, what is the difference between a UV and a UV-C? I am looking at these from GuppiesAquariumProducts.com.au
http://www.guppysaquariumproducts.com.au/uv-sterilizers/uv-c-sterilizer-internal-koi-/pond-/aqu-tank-9-watts/prod_37.html (UV-C)
http://www.guppysaquariumproducts.com.au/uv-sterilizers/self-contained-uv-filter/prod_342.html (UV)

The UV one (second link) is a "self contained UV filter" - what does this mean? Is it a UV steralizer inside a hang on filter?

What sort of specs should I be looking at? I think the UV-C is 9watt, flowrate 800l/h. The UV "Self contained filter" is 5W (i think - power head?, and 500l/h flow rate. It will be for a 6 foot, 300L tank that currently has a fluval 405 filter (1300lph). Will either of these two uv's be suitable? Which one do you reckon is better?

Thanks for your all the help

[ILLUSN]

uv c is they type of uv light used to kill microbs, uvc is germacidal, all uv steilizers use uv-c bulbs. an external uv needs to be coupled to an external filter/pump, both uv's you've posted are internal they have their own pump. both are undersized to be of any use to you.

if you want an intermal use this
http://www.aquariumproducts.com.au/catalogue_products.php?prodID=3340&catID=51

for an external to run off your fluval you'll need atleast this

http://www.aquariumproducts.com.au/catalogue_products.php?prodID=3698&catID=51


what ever unit you choose stick with 1watt of uv / 20L/hour flow rate and you'll be fine.