# Need some advice on UV installation on a canister filter



## dragam21 (Mar 23, 2014)

Why would you use a splitter? Just put it on the outtake and you should not use a check valve, really no need for it. You can still shut off the light, the water will still flow threw it!


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## exv152 (Jun 8, 2009)

Agreed, no need to split. You won't notice much of a reduction if any in flow.


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## manlyfan76 (Jun 20, 2013)

Id put a ball valve on each of the split lines to gain total control of the dwell time. the slower the water passes the uv lamp the more stuff can be killed.


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## exv152 (Jun 8, 2009)

manlyfan76 said:


> Id put a ball valve on each of the split lines to gain total control of the dwell time. the slower the water passes the uv lamp the more stuff can be killed.


Except, to get effective full uv sterilization for algae, bacteria and parasites, which is a level 3 sterilization, you need a flow rate of approx 50gph with a 9w bulb. I would not suggest reducing your flow rate from 205gph (what a 206 is rated) to 50gph. And for the uv to just be minimally effective against algae you need a flow rate of 120gph. Decreasing the flow of a pump dramatically can cause issues such as shaft fatigue stress over time.


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## Moyercrab22 (May 7, 2014)

Hey thanks for the great advice. Based on the responses, I plan not to use a spillter or check valve. Will install directly to out-take of the canister filter. 

@exv152 just to expand on your response. My fluval 206 is rated max 205gph, but it also has a Flow rate lever for adjustments. I'm not sure what the MIN flow rate for this canister is. Anything lower than 50 gph via the UV will most likely heat the water, right?
So my goal is to stay within the range ( 50 gph- 120gph) passing via the UV.
If I'm looking for effective sterilization to remove free floating bacteria, parasites and algae, should I stay around the lower end range of 50gph or the high end range?

Thx again for all the informative responses


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## thedarkfinder (Feb 29, 2008)

Moyercrab22 said:


> @exv152 just to expand on your response. My fluval 206 is rated max 205gph, but it also has a Flow rate lever for adjustments. I'm not sure what the MIN flow rate for this canister is. Anything lower than 50 gph via the UV will most likely heat the water, right?
> So my goal is to stay within the range ( 50 gph- 120gph) passing via the UV.
> If I'm looking for effective sterilization to remove free floating bacteria, parasites and algae, should I stay around the lower end range of 50gph or the high end range?
> 
> Thx again for all the informative responses


Sorry to bump in, I have dealt with uv sterilization for years. 

The fluval 206 is rated to 205gph at the head with zero media. It will stop pumping at 4.8 feet (ie max head height). Now the water flow rate usually will slow down dramatically in the last foot of the pump. So if you have your aquarium 36 inches off the ground with a pump height of 2 feet, you are probably pushing 100-120gph on an empty basket anyway. 

Adding media will reduce your pump down to 60-90gph. 

Now the terrible lie. 

You 9 watt uv light will kill most bacteria, parasites, and algae as longs at it is under 150gph and you have clear water. Faster the water flow, the more times it will take to kill it. So, it will take just 10 minutes to kill x parasite at 20gph, but it will 50 minutes at 100 gph. The amount of time it takes to do enough damage to the organism times the number of times it goes into the uv filter. 

But when you have cloudy/algae water, then you need to slow it down. 

Bottomline. 

Professional uv filters for drinkable water are about 10 watts, they pass the water over the 10 watt blub at 3 gallons per minute (90 gallons per hour). You are not drinking this water. This water is also going to go through the filter about 5 times in one hour. 


In 5 passes anything alive is going to be dead. Don't worry about the speed of the water, your pump really can not pump enough water do anything wrong. 

If you need to slow the water down for cloudy or algae, then get yourself a little mini pump, anything that will do less then 20 gallons at 1 foot head height.

And this will only kill anything in the water column. Most parasites/bacteria will go to the substrate. So you are mostly looking to keep the water clear.


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## Moyercrab22 (May 7, 2014)

Very Helpful Thanks @thedarkfinder
I plan on installing the UV this weekend.


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