Does UV sterilzer increase water temp

[PeterV]

I have a new 215 gal aquarium 4 days old.

The water temperature is steadily rising and is now at 25+ celcius. I've turned off the heater thinking that is was malfunctioning but did not decrease the temp of the water - the temp continued to increase.

My question is - could it be that the UV sterilzer increases the water temp?

I have a Laguna 55 watt.

If it does heat the water could it be put on a timer? and if so, how long, for the sterilzer to be effective, should it run for?

Comments will be appreciated.

Thanks

Peter

[Moon]

The UV lamp does put out a small amount of IR which turns to heat energy. This should not increase the temp of your 215 g tank by a significant level. Make sure that the ballast is not close to the water line. If you are running UV it is best to run it continously. Intermitent use may cause problems.

[Dave C]

What problems could it cause? Many people buy oversized UV sterilizers and put them on a timer. It is often cheaper to do this as the bulb lasts longer and the higher wattage bulbs don't cost appreciably more then the lower wattage.

[Moon]

As I understand it UV is used to kill parasites and bacteria that may be present in the water. By using it intermitantly you might encourage the bacteria to become immune to the radiation and they might even mutate. It's just my theory. I don't use it in my fish room. I was told by a well known local hobbiest that UV weakens the immune system of the fish. He had purchased a group of very expensive African chiclids from a doctor. These fish were in a system with UV. Jim got them to his fish room and put them in a large tank with some other African chiclids. The next day all of his new fish were dead. Now, he is a very experienced hobbiest and did all the right aclaimatation procedures. He could only attribute the deaths to the UV treated very clinical waters they came from and could not handle the pathogens in the water column.

[Dave C]

There are two unrelated issues you're discussing in your post. One is that intermittent use of UV creates bacteria immune to UV, or mutated bacteria. I've never read any evidence or even allegations of that. There are books written on sizing a UV unit for your tank and they recommend that you oversize it and put it on a timer. There is no suggestion that this could have an adverse effect. If you're interested maybe you can find Escobal's "Aquatic Systems Engineering: Devices and How They Function". It's an excellent discussion on UV as well as other water issues.

As for UV affecting the immune system, again I've never seen evidence of that. But any time that someone has fish deaths they look for reasons. If the vendor used UV then that is a good reason, whether it's true or not. What about the hundreds (I'm assuming here) of other sales by this vendor that did not result in deaths in his customers' tanks? They didn't have deficient immune systems? It doesn't make sense that only one customer would have fish that suffered. Nor does it make sense that the many other breeders out there that use UV don't have similar complaints from customers. Any claims of deficient immune systems that I've read are similar to your story, anecdotal at best.

[Dave C]

btw, the way we use UV in our tanks is intermittent to begin with. Even if we run it 24/7. Regardless of the size of pump you use to drive the water through the unit the bacteria in the tank is exposed at random intervals throughout the day. If intermittent use was a problem then you would have to have a very strong UV light shining on the tank throughout the day & night. Instead it is exposed to the light at intervals of however long it takes to turn over the tank contents. The premise of using a timer is that you determine the length of time it takes your pump to turn over 99.99% of your tank. Then you buy a timer and set it so the UV kills 99.99% of the pathogens in your tank once or twice a day, depending on what you're trying to kill. Anything beyond that is overkill.

[korbi_doc]

Good answers Dave!!!! Dottie