Billaney Posted January 7, 2006 Report Share Posted January 7, 2006 Hi Does anyone know much about these things ? they seem to read like the ultimate fish health and alge removeing device. http://www.trademe.co.nz/structure/0004 ... 986480.htm Do they work ? is it that easy ? Your thoughts would be great . Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted January 7, 2006 Report Share Posted January 7, 2006 I don't know much about this particular product,but I built one years ago and did a lot of reading at the time. There are some very important factors in their operation, such as: depth of water to penetrate (only effective on shallow depth of water) Clarity of water (cannot penetrate water with turbidity) They have an effective operating temperature. Has to have sufficient contact time to be effective The bulbs need to be frequently cleaned or UV is blocked off. Must be shielded from eyes (damaging to eyesite) People sometimes forget that there are billions of different microorganisms out there and 99.99999% are harmless or good. We would not do well in a sterile environment and neither will fish. Quote Link to comment Share on other sites More sharing options...
Warren Posted January 8, 2006 Report Share Posted January 8, 2006 For a UV filter there is a fairly general rule called 4. 1. The UV must cantact the water for at least 4 seconds. 2. The UV only effectively kills 100% of organics to a depth of 4mm. And thats it. If the flow rate is too fast it will not be as effective. If the water is too deep past the tube it will not be as effective. The flow rates shown in the add are a bit on the high-side to get a 100% kill of bacteria and algae. They will still be effective though. Work on about 1 watt for every 50L of tank size. So 5W is good for about a 250L tank to keep it crystal clear and disease free. The problems I've experienced or know about with UV are: 1. Fry don't like them operating on their tank. 2. Fish living long term are much more prone to disease if moved to a tank with no UV. 3. Nitrates go up faster. 4. Kills Pollyps on mirines (way reduced colonisation). Other than that, if sized correctly, they work great. I used to use a 40Watter on my fishroom (when it only had 2000L of tanks on a central filter). There was never any algae in the tanks and no disease when it was running. I used to run it for a couple of weeks after adding new fish and for about a week now and then to get rid of algae buildup. I made mine by getting a 40W UV Germicidal Tube from Mastertrade (about $100). Got a piece of PVC pipe with an inside diameter 8mm bigger than the tube diameter (so there was a gap of 4mm between the tube and pipe. I glued endcaps to the pipe and siliconed the tube onto the PVC pipe. This way the water directly contacted the quartz tube for best performance. I worked out how much water was in the pipe (PIr² of PVC Pipe ID - PIr² of the tube (3.1415x16.5² - 3.1415x12.5² = 855.27mm² - 490.86mm² = 364.41mm²) x the length = 364.41mm² x 1180mm = 0.43L) The flow rate was set to 0.43L/4 seconds x 60 seconds in a minute x 60 minutes in an hour so 387L / hour. This guaranteed a 100% kill rate of any living organism going through the UV unit. Quote Link to comment Share on other sites More sharing options...
Billaney Posted January 8, 2006 Author Report Share Posted January 8, 2006 Thanks for the great info guys I knew someone in here would know Thanks again Quote Link to comment Share on other sites More sharing options...
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