Diana K

Cliff is exactly right. However, nothing is 100% effective, anyway. Whichever solution you decide on for any specific problem, research so you apply the method correctly, and have a back up solution in mind in case the first solution does not work for whatever reason. Often a combination approach is best.

Another note about UVs: Many fish medicines are light sensitive, and UV will deactivate the medication, too. If ANY research suggests turning off the tank light while using that medicine, then turn off the UV, too.

catklyst

none of my fish are sick im just worried after reading about worms and such people get in some of their tanks

ObiQuiet

I had the same questions to-UV-or-not-to-UV (I'm new at this). Here's what I did, after weighing pros and cons.

I got the in-tank Submariner, 5W. This sits inside the tank, and has a built-in pump.

My rationale was:
a) I wanted water movement in the tank, but not the surface aeration.
b) The "insurance" is comforting, since I don't yet trust my abilities. So, it makes me less nervous when a fish flashes from time to time.

Since it's just a 5 watt, I've let the filter clog a bit to reduce the water flow and increase the dwell time. (BTW, In my reading, UV ratings/rankings seem to consider only the one-time hit of UV and don't consider that the aquarium water cycles through it many times per hour, 24 hours per day. As far as I can tell, this should make even a 5 watt bulb overkill for a 40g.)

I was worried about the known effect of UV light removing usable iron from the water column. Ms. Walstad assured my that I'd be able to find a duty cycle that still kept the floating plants in good shape. So, I have the UV on a timer that runs for 2 hours out of every 6. Will adjust as needed.

-ObiQuiet

Diana K

Water that passes through the UV several times in a day (or even in an hour) is not really going to kill something that needs to be exposed for a long time. Slowing the water flow will do this. The 'bugs' will stay exposed to the light for a longer time all at once. With shorter exposure they might heal in between trips.

Also, I see an inconsistency in your comments: You are hoping that running it 24/7 will increase the exposure of the pests to the UV, yet your plan is to run it intermittently.

ObiQuiet

Diana K,

You're right. I wasn't very clear. Maybe this will be a better explanation...

In my amateur web searching, I didn't find any documentation about the efficacy of multiple passes. All of the info I found was about wattage and one-pass dwell time.

I've slowed the water flow by letting the filter get dirty. Consumer mis-understanding is the only reason I can think of that the mfgs don't advertise how _slowly_ they can pump the water...

Right, they might. I have no way of knowing if the 15-20 minutes between trips through the UV is long enough for some of these organisms to heal themselves.

Sorry for the confusion -- I meant to point out that none of the info I could find took into account the possibility of 24x7 operation and multiple cycles of the UV in judging how many watts you need or the dwell time.

I am running mine intermittently for these reasons:
a) I don't expect any introduction of new pathogens, so running it all the time seems like overkill. If the water cycles 3x per hour, and 3-5 passes are fatal, then running it long enough so that I get 90% odds of each organism passing the light 10x per day seems ok.
b) The UV does affect the growth of floating plants (hornwort is dropping needles and the duckweed growth has slowed down)

In short, I'm still guessing and trying this stuff out... and making lots of assumptions.

Cheers,
-ObiQuiet

bartoli

The newer shipment of Submariner includes a flow regulator that you can use to significantly slow down the water flow. If you don't have it, request one by contacting JBJ Lighting at http://jbjlighting.com.


That is consistent with my experience.

ObiQuiet

Great, thanks!! That will be quite nice to have.

Alexpatrascu

I'm planning on getting one on my 50 gal and attach it to my Eheim 2217.....better safe than sorry....

barbarossa4122

Hi,

I have 2 9w GKM. A few days ago I noticed that one of the led 's indicator light from one of the sterilizer got much dimmer than the other one. Do you guys have an idea why? I only used them for about 6 weeks 24/7 but now they are on a timer for 15hrs/day. Thank you.

flashbang009

might just be a faulty light. They aren't the highest quality hardware. Maybe try unplugging it, and plugging it back in. Other than that i wouldn't worry about it.