Im using a V2 vecton UV water steriliser and the bulb is dying, so i have to replace it, this is the first time i have used 1 so can someone advise me on what bulb to buy, i have been on the website and their option are
Standard Bi-Pin Replacement UV Tube 4w £5.99
Standard Bi-Pin Replacement UV Tube 6w £5.99
Standard Bi-Pin Replacement UV Tube 8w £7.09
Standard Bi-Pin Replacement UV Tube 15w £8.11
Standard Bi-Pin Replacement UV Tube 16w £8.11
Standard Bi-Pin Replacement UV Tube 25w £10.14
Standard Bi-Pin Replacement UV Tube 30w £10.99
Standard Bi-Pin Replacement UV Tube 55w £18.99

So what's the difference between the 4w and the 55w?
is that the strength of the UV bulb?
i dont know what 1 i have in my tank now, so what do you suggest i use?
i have a 136 uk gallon tank.

I do use UV Sterilization. Here's the catch I keep track of.

What are you aiming at using UV for?

Take into consideration that there are three main uses you could adjust (at least theoretically) your UV unit.
a) algae control
b) bacterial and fungal control
c) parasite control

For each of these ones, a different flow range is required. I use my unit to aid in algae control, so I set the flow at a target range of 40-50 times per UV Wattage lamp. So, the higher the Wattage, the more powerful pump/power head needed.

Also for aquarium tank, the turn over rate should be, at minimum one to one and a half times its volume.

You use those two requirements and find your suitable UV Wattage lamp. I use a 13W lamp now and likely will downgrade to 9W when I replace my lamp this month.

Carl Strohmeyer suggest the following, as a guideline:

5 Watt UV: 10-100 gallons (35-375 liters)
7 Watt UV: 20-150 gallons (75-570 liters)
9 Watt UV: 40-200 gallons (150-750 liters)
13 Watt UV: 50-250 gallons (190 -950 liters)
15 Watt UV: 60-250 gallons (225-950 liters)
18 Watt UV: 100-300 gallons (375-1150 liters)

I invite you to read his article on UV Sterilization:
www.americanaquariumproducts.com/AquariumUVSterilization.html

Pepe
Santo Domingo

To be honest with you, im no expert with UV, when i bought my setup, it come with a vecton 400 and the bloke told me i'll need to replace the bulb soon, which i need to do now.
i asked him what the UV done, he said to me as long as its left on, you should have crystal clear water, which it has done.
so basically i want it to keep my water clear and whatever else it can do.
i dont mind buying the highest wattage 1 but whats the downfalls to it?
because surely everyone would buy the highest wattage yes?

sorry guys and gals.... i used to install those UV things
in water purifying stations but i never got the nerve to
go about its function. i am just a plumber then who do the
piping works.

I managed to get the cover off the vecton uv, and it had a 15w bulb in there, so thats what i have ordered.
pepetj... does that seem right to you?
i have a 136 uk gallon tank with 2 tetratec 1200's running.