Please take what I say as just my opinion. I've noticed (not necessarily on this forum or this thread) that some people have *very* strong opinions on the pro's and/or con's of UV Sterilizers. I have no desire to get into a religious debate about the devices. All I can tell you is my own (brief experience) and what I've learned from reading a lot of books, a lot of forums and talking to some people online including.
I think a UV Sterilzer is a good thing and it's my intention to use one long term. I would never say it is a waste of $, as some do. To me, it's just another tool in the fight against negative things in our aquariums.
It is not, in any way, a replacement for other good practices which we all know about such as, but not limited to: regular water changes, use of RO/DI, buying your livestock from reputable sources, proper flow and movement, using a good skimmer and most importantly quarantine. It's just another weapon in the arsenal.
In my case, it worked. Fast too. I had been dealing with cloudy water for 2 weeks, maybe more thinking back. Whether or not the cloud was bacterial is not for me to conclude, as I'm not a marine biologist (I'm an electrical engineer if anyone cares, IT guy now who dabbles in development). All I know is the sterilizer I bought cleared my clouds in less than 24 hours. I'm *assuming* that means it cleared things up by irradiating the negative bacteria. I'm also assuming it killed some things I wouldn't want it to kill, but I'll get to that later.
What I'm kicking myself for is 2 things. The first is that I didn't get one sooner. I don't know what the cause of death of my 2 clownfish was. All I know is that they died DURING the bacteria bloom, when it was at it's peak, and after multiple huge water changes which did nothing for the bloom. The UV however, corrected it (or at least the clouds that were a result of it) in a matter of hours. Were the deaths coincidence? Maybe. I don't know. I highly doubt it. Maybe the bloom was just a stress-or that made the clowns susceptible to whatever disease felled them. Maybe it was the bloom that killed them directly. I just wish I had used that weapon sooner. Maybe my clowns still would have gotten sick. Maybe I still would have lost them. Maybe I wouldn't. All I know is it was a tool I didn't use, and I regret that.
However, what I regret more is not QT-ing the clowns in the first place. That was dumb of me. I know I'm supposed to, but I didn't. I was lazy and cheap and impatient. It goes without saying that I've learned that lesson to the tune of 50 $ and a sad girlfriend who had gotten attached to them (as I did) OK, in theory, they would have gotten sick in the QT tank and may or may not have been curable there in the first place. Or maybe they wouldn't have contracted what they did until they got into the display. Or maybe they brought it with them and maybe in those latter 2 cases a UV unit on my display would have prevented that transference. Again, I can't say for sure. All I know is, QT? Yeah. Do it. Furthermore, at least in my case, my QT tank will have its OWN UV sterilizer because like I said, it's another tool, another precaution and I'm taking it.
Now I haven't spoken about $. Yeah, they cost $. I don't like throwing $ at problems. In fact, I hate it. It fails as a method of doing things 50% of the time. That probably held me back from buying one sooner. My advice when it comes to whether or not it's worth the investment is to look at what you're spending on elsewhere in the hobby (especially on meds and additives to allegedly clear your water or cure disease) and do some math. We all know a QT tank costs very, very little $, so again, a UV unit on your display tank is neither a cost effective alternative to QT nor a smart one. But if you're buying bottle after bottle of chemicals or something like that, you probably would have already paid for your UV sterilizer.
The unit I currently have in my tank is a thing I got at Petco Wednesday night because I wanted something NOW and it was the only thing I could get local:
http://www.petco.com/product/114522...Internal UV Sterilizer with Power Head-114522
You can see it in my pictures on the fair left. It's the big black cylinder looking thing on the left. The long part is the bulb chamber, water enters about 3/4 of the way up through a sponge goes down, then back up, and exits out the top via that 90 you can see. It's a completely self contained unit. It comes with a pump, sponge filter, bulb chamber. You could put it in a sump, but I didn't have room in mine for something that large, especially after putting in such a big skimmer the other day.
I wound up with the 24 watt model - ie the biggest one - because that's all they had at the store. It's almost definitely over kill for my needs (50g tank) which is why I don't plan on using it long term. On Monday I'm getting a Coralvue Turbo Twist 18 watt that I'm going to plumb inline to my return as you and someone else were talking about in this thread earlier. It's just going to slide into one of my return legs and sterilize all the water coming back up my return (well half of it - I split my return to either side of the tank, but turn over is turn over). I'll probably put a valve right before it so I can regulate flow through. I think it's a more subtle solution for the long term.
I also think that unit is more reasonable for my needs, wattage wise. My understanding is that you can have TOO much UV if you keep a reef. Remember, you ARE irradiating everything that passes across the bulb. Yes contact time and wattage matter, but I don't know all the details or understand them. Best thing to do is probably 1) not believe mfr recommendations on size and such and 2) talk to people with units who've had them for a while (ie not a noob pants like me) and see what size works best for your environment.
Anyway, sorry for the long winded response. I got started and didn't stop. I do that sometimes
Good luck!
