I run one 24x7 and do not see any side affects... The main thing to remember is benificial bacteria colonizes the surfaces of the rocks, substrate, tubing, resevoirs, etc... very little is in the water column. Now, the thing is, like Kevin mentioned, unless it is sized correctly and even a little larger for the tank size, it will probably doing more harm to the electric bill than the tank...UV
lights are not a cure for harmful bacteria and protozoans, it is mereley a preventative piece of equipment. If used properly and continuosly, it is a good piece of equipment to have..
Make sure that the UV
is installed after a prefilter so that no big particles are introduced through the UV
. This will help keep the pathway clear and help the UV
do its job more efficiently..