i have purchashed a uv steralizer and now have it in the tank the water is pretine at the moment i would like to know if i have to leave it on all the time or can i turn it off ive never had one of these.
Run it as little or as much as you want - some just run it for a day or two at a time when they feel they need it - others runs theirs 24/7 (and of course replace the bulbs much more often).
I use mine on a regular basis, for weeks at a time, and find that it helps to keep my tank water crystal clear 100% of the time - this of course along with frequent wcs, strong filtration, a rigorous media cleansing routine, and the use of Purigen and filter floss, as well as the use of fine pre-filter sponges on the filter intake tubes.
Not to mention the job a UV does in ridding your tank of any floating algae in the water column and harmful pathogens.
I recently went from running my UV sterilizers 24 hours a day to running them on a timer for about 12 hours. I also set one up as a sort of control that is 24 hours, and one that I only run for about 12 hours once a week. So far (3 weeks) I have found that all of the tanks with UV on them have equivalent water quality. I want to test this a bit further, but so far it looks like if you put it on a timer for a period each day that will allow all of the water in the tank to go through it about 5 times that would probably be enough for most uses. More data will follow as my experiment continues.