UV sterilizer placement

[salt210]

I was looking at the plumbing on my tank while trying to figure out the best place for placement of the sterilizer. The question that I have is what do you guys think would be the best place for it? The line coming out of my return pump splits into 2 before going into the tank. would it be better to put in before or after the split?

 

[aquaknight]

Yo! Fellow O-towner!
The ideal placement of a UV, if I'm not mistaken, is after some type of filter. That way you only get the micro-organisms, and not large pieces of junk floating through.
I have mine, maxijet 400 pumping into a phos reactor (AquaC XP+), then into the UV (aquanetics (sp.?) 15w). Seems to be the right amount of flow.
So IMO, if you can, stick it somewhere else eariler in the sump.

 

[scsinet]

A UV unit should never be simply installed in a return line wide open, but should be put into a line carrying filtered water.
UV units require very low flow, on the order of 5gph/watt or even less to achieve a good "kill." Almost everyone's return line is far more than this amount.
The best way to hook it up is to place a dedicated pump into your sump's return area that runs at the correct flow rate, then to loop the output back to the sump.
You can "T" off your return line, but you need to set it up in such a way that the flow is able to be regulated. I run mine by coming off the return line, then through a ball valve and back to the sump, so it's easy to regulate the flow. Of course, this cuts down on the maximum flow into your tank, so your return pump needs to be somewhat oversized to do this.

 

[salt210]

so I shouldnt have it at maximum recommended flow for the sterilizer? A small 125gph powerhead would work? Its a 25W. I was thinking that putting in line would slow down my flow anyways.

 

[scsinet]

Well the "maximum flow rate" is likely going to be a flow rate you wouldn't want. Going too fast will prevent it from killing the really bad stuff like Ich. Slower is usually better.
The powerhead you have sounds about right.

 

[salt210]

I dont have one yet, I was looking yesteraday and all that I saw was either too low of a rate or a little over, roughly 135gph

 

[aquaknight]

Don't forget to calculate the amount of head loss per ft. of tubing you're planning on running as well.

 

[farslayer]

Low flow rates thru a UV are not necessarily ideal or required. Many UV sterilizers support higher flow rates by exposing the water to the light for longer periods of time over a longer path. The wattage is not as relevant as the length of the path along the bulb. For instance, if I have a one foot path good for 200 gallons per hour, a two foot path would allow for 400 gallons per hour, all things being equal, since the water would be exposed for the same length of time. If I cut my flow down to 200gph over a two foot path, I would effectively double the exposure time. Remember that pushing the water across at higher speeds does not diminish the effectiveness if the water is exposed for sufficient time; the water flow will not outrun the UV light, the time of exposure is of the most importance.
Basically, follow the manufacturer's specifications. Too slow and it's not effective, too fast and exposure time is diminished.
Cheers, and happy sterilizing
Quick edit: SCSINet is absolutely right, some critter need longer exposure times, such as ich. Good call!