View Full Version : Need help with my U.V. Sterilizer...

01-13-2007, 11:53 AM
I have a 9 watt U.V. Sterilizer attached to my Rena XP3.....I purchased the U.V. used. I understand that the bulb needs to be replaced about every six months. I'm not sure how old the bulb is now...How will I know that it needs replaced? I know the easy thing to do would to be just replace it, but I don't like throwing money away (When I could spend that money on fish). Will the light burn out, or does it just lose its effectiveness?

Thanks, MIKE

01-13-2007, 12:07 PM
UV bulbs have what are called halflives. meening every X time their intensity falls by 1/2

most bulbs in production now, have a 6 month-1 year 1/2 life.
with few bulbs being usefull for 2 halflifes (not many)

there are sensors that can be used, or just mark it on the callender. another uption is to regulate the flow through a UV filter, folling the first 1/2 life, you can often crank down the flow (water stays in the finter longer) and get an extra 3-6 months out of it (I only mention this as it sounds liek your trying to save a buck or 2.)

01-13-2007, 12:51 PM
Thanks for your help...Not really trying to save any money, I just don't want to replace my bulb before I have to....I'd rather spend the money elsewhere. But my ultimate goal is to maintain a healthy aquarium for my fish.


01-13-2007, 08:33 PM
then mark it on the housing. common practice.

01-13-2007, 11:15 PM
to my knowledge most fish UV systems use low presure low intisity lamps. most have about 8,000 to 10,000 hours of life. NB is correct about lowering the flow, you can gaurantee proper dosage at lower intensity(older lamp)by doing this. I have changed many UV lamps at wastewater treatment plants and visually they may have a smokey look to them when they are older but this is not alwyas the case. i have seen old lamps with very little visual evidence. a new lamp will produce 190 Mw/cm2 at one meter distance in the 254 nm range. at 5000 hours it may produce less then half that but is still very effective. if the Quartz sleeve is kept cleen i have seen lamps work at 70to 80% loss but you are taking a chance. if the lamp was used 24/7 for a year i would definatly change the bulb. you should also clean the sleeve to insure maximum efficiency. if it wasnt used all the time i woudl clean and inspect it. it might have some life left in it.

01-14-2007, 07:42 AM