[Steven Pro]

Yes, contact time does make a difference, but I don't believe there is a difference if water flows through a 12" long 2" diameter pipe at a relatively slower flow than 48" of twisted pipe that is only 1/2" at four times the flow rate.

By the way, these are gross generalizations and not the complete story, but you should get the idea.

[jollopee]

I totally agree with you in some aspect, but if someone is pushing water through at a quicker rate then wouldnt the twisted tube be a better way to go? Like my UV is tied into my return line from the fuge, which is pushing about 600gph. Now the UV is rated at 900gph so I assume Im getting some good contact time. Someone that has a smaller pump specificaly for their UV and can slow the flow down drastically I would say that, yes, a straight run from end to end of your UV would be sufficient, I would think that each style of UV has its own unique place. If I had 10 feet of tube wrapped around a 3 foot light it would take longer for the water to completely make a pass by the bulb as apposed to a 3 foot tube with a 3 foot light, useing the same pump of course.

Todd

[Ninong]

Originally Posted by jollopee

Now the UV is rated at 900gph so I assume Im getting some good contact time.

What exactly do you mean when you say "the UV is rated at 900gph?"

Is that the maximum flow rate? That's the number most manufacturers advertise when they say their unit is "rated" at such and such gph. If so, that has absolutely nothing to do with the effective flow rate.

What wattage is your lamp?

You need to adjust your flow rate so that you get 90,000 µw/cm² because that's the dosage required for saltwater aquariums to kill such things as saltwater ich.

[jollopee]

Originally Posted by Ninong

What exactly do you mean when you say "the UV is rated at 900gph?"

Is that the maximum flow rate?

25 watt, I said it is rated at 900 but is really 1200 and I said gph because that is how us simple folk or simpletons relate to things like this. Ninong, as for your 900000 number are you trying to confuse me( If so you will never penetrate the thick skull that is protecting my brain ) Hell I cant even type that upside down h thingy....anyhow. Sooo, if that is rated at 30k h thing @1200gph then at 400gph I would be achieving 90k right?

Todd

[Ninong]

All of the so-called rating numbers you are quoting for your unit are meaningless.

A 25w UV can be rated at 2,000 gph. That simply means that you can run 2,000 gph through it if you're using it on a freshwater pond and all you want to do is clarify the water. That doesn't mean it will be very effective at killing anything.

Every independent UV comparison test that I have read over the past ten years or so rates AquaUltraviolet as the best out there. It is also one of the most expensive.

Their 25w lamp is "rated" to handle a maximum flow of 2,000 gph when used to clarify pond water. It won't kill off anything. The same 25w lamp must be run at 400 gph to produce 90,000 microwatts per square centimeter, which is the dosage required to kill ciliated protozoans, such as Cryptocaryon irritans.

Here is AquaUltraviolet's sizing chart. Notice that their 25w lamp is rated to handle a 4000 gallon freshwater pond when used as a clarifier but only a 500-1200 gallon freshwater pond when used as a sterilizer and it is rated for only a 150 gallon marine aquarium. That's because the marine aquarium requires a much stronger dosage to kill off nasties.

[jollopee]

Got ya, thanks for the break down. Im off to buy that UV right now

[asmodeus]

I have a 36 W twist on my system, I dont know if it's working ,but the ick hasn't been around on my tangs I give it that. To clean My UV mine is on a great system. I have my 20 gal frag tank plumbed to my sump and it is getting fed from the hagen 800 power head and the out put UV goes to the 20 gal and then draines to the 20 gal and back to the sump via the drilled hole. I will post a pic's to show ya. all i have to do is un plug the UV unit and wait for it to back siphon then clean it