I have used them for years. I am on my second one now. I like them for added insurance. They kill single cell agae, bacteria, free floating parasites. That is the Pros in my oppinion. I have heard people say that fish that come from UV sterilized water are more prone to disease in tanks without UV sterilized water. If you get a fish from someone and you have a UV sterilizer hooked up why worry. Just my oppinion,
OK the UV filter is up and running. This took almost 2 hours as I had to clean the skimmer and remove all bio balls and drain plate to put pump under them.
I have the cord and 1/2 inch feed hose going under the sponge that is dividing the bio balls and the skimmer and return pump area.
Once everything was connected and tested for any leaking I put most of the bio balls and drain plate back in place.
The return line from UV is going back into the sump and was put over the sponge. (changed this and put is close to tank return pump)
The 1/2 rigid tubing with the quick disconnect fitting allows me to be very flexible with where I can move the UV or the return line or for removing UV to clean.
So far I am happy with the set up.
I got the Lifegard 25 watt one on sale over at Dr.Foster and Smith
The only cons that I can think of with a UV sterilizer is initial upfront cost, the fact that you have to keep them clean, and the cost of the replacement bulbs. Other than that, they kill a LOT of the things we don't want in our tanks. Like Ed Hahn said....good insurance.
Here's a link I pulled out of the RF Resource Library (I tend to spend substantial time in the Resource Library and that's why I put it in my signature).
I have a used 18 watt unit (with a new bulb) but I will eventually buy the same unit that Dave just posted.
The reason that it is important to keep them clean is that if the quartz tube is dirty, you don't kill as much. They also operate best off of low flow so the bacteria/algae/parasite, etc. are in the chamber long enough to be killed. My unit runs off a very tiny powerhead.
on a 72 all you need is a 9 watt. I run the customsealife double helix unit , which runs the water by the bulb twice in one pass. The material the water chamber is made out of does not seem to get dirty like the glass tubes do. The only thing you need to do is place it in a spot where if you add your chems for alk and calc that they don,t pass imediatly through the unit because it well calcify in the water chamber from the lite i guess. They just hang on the side of my sumps with the littlest maxi jet ph and plug them in. No muss or fuss, very easy to get running and i check mine every six months for cleaning which i have never had to do yet in 3 yrs, change the bulb out once a yr. and the 9watt is good for 150 gals so even cut in half that means 75.
You really can't say what wattage you need for any size tank.
If you read the link above you will see that all the companies have different ways of testing the UV's and it really depends on The pump that is pushing the water through the unit.
Either it was Curt or Mike that told me to get the biggest one you can and take the GPH of the UV and divide that by half or more.
The longer the water hits the UV light the better off you are, so here use a bigger UV and a small pump.