It depends on what you're trying to accomplish. The UV that comes built into filters is probably not strong enough to do much other than maybe clear green water. A dedicated UV depending on the wattage and flow rate can do a lot more, like potentially kill diseases. You will rarely need a UV sterilizer, and you can hook one up if and when you do need it. The bulbs will eventually die and depending on what fixture you have they can be expensive to replace.
I set up an aquatop 10w UV sterilizer plumbed inline with my canister filter on one of my tanks, just because I thought it might help clarify the water. It came with 2 bulbs and I ran it on the same timer as my lights / CO2. After I burned through both bulbs I just unplugged it and left it inline. I haven't had a need to replace the bulb yet since that tank is doing fine. Replacement bulbs for that model are only about $13 so I may end up using it again on another tank at some point.
Long story short, you probably don't need one if you're not having issues, and even if you are it may not solve them. But if you just feel like hooking up a gadget for your own personal interest, it's not going to hurt anything.
I set up an aquatop 10w UV sterilizer plumbed inline with my canister filter on one of my tanks, just because I thought it might help clarify the water. It came with 2 bulbs and I ran it on the same timer as my lights / CO2. After I burned through both bulbs I just unplugged it and left it inline. I haven't had a need to replace the bulb yet since that tank is doing fine. Replacement bulbs for that model are only about $13 so I may end up using it again on another tank at some point.
Long story short, you probably don't need one if you're not having issues, and even if you are it may not solve them. But if you just feel like hooking up a gadget for your own personal interest, it's not going to hurt anything.
