UV / Turbo Twist / Aqua Step

DaveWC · 10/03/2006, 01:19 PM

I'm looking at all of the hoopla about the different ways to build a UV sterilizer. You've got Coralife with their twisting design & now Lifegard has the step model. Both suggest that the little maze they make for the water around the bulb increases the dwell time. It just doesn't make any sense. If you have a bulb and you pass water past the bulb at X gph then the water will start and end it's exposure to the bulb at exactly the same time regardless of any twists or steps that you introduce within the casing. If anything that garbage will slow down the flow but if you desire X gph of flow then you'll just bump up the gph of the pump or open the ball valve more. So isn't it just hype? Isn't it just a bulb in a casing with water going by it?

crispyreef · 10/03/2006, 01:38 PM

Think of the water as a filter on the uv light. If you have a large volume of water pass the bulb, it may only be affective to the water that is closest to the bulb. So the twists and turns are hopefully allowing the water furthest from the bulb to be closest on the next twist or turn.

DaveWC · 10/03/2006, 01:45 PM

I don't think that's particularly relevant. Water is transparent and ideally you're pushing clean, filtered water past the bulb so the uv should be equally effective as it moves past the bulb with or without the twists. And both Coarlife & Pentair (Lifegard) state in their ads that their design increases the contact time allowing for longer exposure to the UV light. Pentair says that their steps triple the contact time. Just sounds like smoke & mirrors to me.

crispyreef · 10/03/2006, 02:00 PM

If water is not a filter, then why do we need to place some corals up high and others lower?

DaveWC · 10/03/2006, 02:15 PM

We wouldn't worry about the placement of coral if our tanks were 3" tall, like the diameter of most UV sterilizers.

I'm not saying that water is not a filter and has zero effect. I'm saying that it's not relevant to the claims being made about these units. The manufacturers claim that the twists & steps increase contact time. Water rushing through a straight pipe at 200gph will take exactly the same amount of time to enter/leave as it would through a twisted pipe. If the flow is maintained at 200gph the contact time within the pipe is the same.

WarrenG · 10/03/2006, 03:54 PM

4-5 years ago I had one of those UV's with the twisting plastic tubing inside. What a piece of junk it was! It was kinked on the end when I opened it up (after it failed within a month of use, and the tubing was not large enough nor clear enough to offer any advantage over just letting the water flow through.

Yes, the twists do nothing for contact time. Contact time is determined by how large the container is, and how much water is going in and out of it. If it holds 1 quart and the flow is 10 quarts a minute then the contact time is about a tenth of a minute. All the twists and turns do not affect the amount going in and out, hence no change in the contact time.

WarrenG · 10/03/2006, 03:56 PM

Quote:

Originally posted by DaveWC

Water rushing through a straight pipe at 200gph will take exactly the same amount of time to enter/leave as it would through a twisted pipe. If the flow is maintained at 200gph the contact time within the pipe is the same.

Righto. Now, would you care to explain that to all the people that think a recirculating skimmer (vs. non-recirculating) increases contact time?

crispyreef · 10/03/2006, 03:58 PM

Instead of increasing the length of the bulb, they have increased the pathway around it, equals more contact time.

crabsy · 10/04/2006, 05:22 PM

shortest distance between 2 points is a straight line. twist adds distance so more contact time. It will take longer through more distance than the straight line at same speed.

sarahdae · 11/19/2006, 12:48 AM

Yes, the twists add more "distance" the water has to travel, but the problem is the water pressure increases and the water moves faster through the twists, so basically the water DOES NOT go through the unit any slower, it is just sped up through the twists, and thus that negates the longer distance. So basically because of the water pressure it will go through at the same speed regardless of how many twists or turns.
In order to actually "increase dwell time" the unit would have to somehow decrease the water pressure, which you would not want.
Thus the more bulb length (larger unit) you have the better, not the more twists and turns!

DaveWC · 11/19/2006, 09:00 AM

The point is moot for me anyways now. I ended up getting an Aqua 114w UV and let the twists/turns be damned. Bigger wattage makes more sense then steps or twists to me.

gabe3d · 11/19/2006, 10:37 AM

The amount of water already inside of the Sterilizer needs to be accounted for so lets say your UV sterilizer is 100 gallon in size and you are pushing 50gph for argument sake. The water that has just entered the unit will not exist until the 2 hours has elapsed. Now lets say you sterilizer is only 50 gallon in size, the water that has entered will exit after 1 hour. The coil or stepping system does help make the exposre time longer.

10/03/2006, 01:19 PM	#1
DaveWC Premium Member Join Date: Aug 2006 Location: Winnipeg, Canada Posts: 217	UV / Turbo Twist / Aqua Step I'm looking at all of the hoopla about the different ways to build a UV sterilizer. You've got Coralife with their twisting design & now Lifegard has the step model. Both suggest that the little maze they make for the water around the bulb increases the dwell time. It just doesn't make any sense. If you have a bulb and you pass water past the bulb at X gph then the water will start and end it's exposure to the bulb at exactly the same time regardless of any twists or steps that you introduce within the casing. If anything that garbage will slow down the flow but if you desire X gph of flow then you'll just bump up the gph of the pump or open the ball valve more. So isn't it just hype? Isn't it just a bulb in a casing with water going by it?

11/19/2006, 12:48 AM	#10
sarahdae Registered Member Join Date: Jul 2005 Location: Queen Creek, AZ Posts: 222	Yes, the twists add more "distance" the water has to travel, but the problem is the water pressure increases and the water moves faster through the twists, so basically the water DOES NOT go through the unit any slower, it is just sped up through the twists, and thus that negates the longer distance. So basically because of the water pressure it will go through at the same speed regardless of how many twists or turns. In order to actually "increase dwell time" the unit would have to somehow decrease the water pressure, which you would not want. Thus the more bulb length (larger unit) you have the better, not the more twists and turns! __________________ Sarah Current Tank Info: 90 gal, mixed tank, 2 250w HQI/2X110w actinic, Deltec MCE600 skimmer

10/03/2006, 01:38 PM	#2
crispyreef Registered Member Join Date: May 2006 Location: North Bay Posts: 1,189	Think of the water as a filter on the uv light. If you have a large volume of water pass the bulb, it may only be affective to the water that is closest to the bulb. So the twists and turns are hopefully allowing the water furthest from the bulb to be closest on the next twist or turn.

10/03/2006, 01:45 PM	#3
DaveWC Premium Member Join Date: Aug 2006 Location: Winnipeg, Canada Posts: 217	I don't think that's particularly relevant. Water is transparent and ideally you're pushing clean, filtered water past the bulb so the uv should be equally effective as it moves past the bulb with or without the twists. And both Coarlife & Pentair (Lifegard) state in their ads that their design increases the contact time allowing for longer exposure to the UV light. Pentair says that their steps triple the contact time. Just sounds like smoke & mirrors to me.

10/03/2006, 02:00 PM	#4
crispyreef Registered Member Join Date: May 2006 Location: North Bay Posts: 1,189	If water is not a filter, then why do we need to place some corals up high and others lower?

10/03/2006, 02:15 PM	#5
DaveWC Premium Member Join Date: Aug 2006 Location: Winnipeg, Canada Posts: 217	We wouldn't worry about the placement of coral if our tanks were 3" tall, like the diameter of most UV sterilizers. I'm not saying that water is not a filter and has zero effect. I'm saying that it's not relevant to the claims being made about these units. The manufacturers claim that the twists & steps increase contact time. Water rushing through a straight pipe at 200gph will take exactly the same amount of time to enter/leave as it would through a twisted pipe. If the flow is maintained at 200gph the contact time within the pipe is the same.

10/03/2006, 03:54 PM	#6
WarrenG Registered Member Join Date: Jun 2003 Location: Sunnyvale, CA Posts: 738	4-5 years ago I had one of those UV's with the twisting plastic tubing inside. What a piece of junk it was! It was kinked on the end when I opened it up (after it failed within a month of use, and the tubing was not large enough nor clear enough to offer any advantage over just letting the water flow through. Yes, the twists do nothing for contact time. Contact time is determined by how large the container is, and how much water is going in and out of it. If it holds 1 quart and the flow is 10 quarts a minute then the contact time is about a tenth of a minute. All the twists and turns do not affect the amount going in and out, hence no change in the contact time.

10/03/2006, 03:58 PM	#8
crispyreef Registered Member Join Date: May 2006 Location: North Bay Posts: 1,189	Instead of increasing the length of the bulb, they have increased the pathway around it, equals more contact time.

10/04/2006, 05:22 PM	#9
crabsy Registered Member Join Date: Aug 2005 Posts: 172	shortest distance between 2 points is a straight line. twist adds distance so more contact time. It will take longer through more distance than the straight line at same speed.

11/19/2006, 09:00 AM	#11
DaveWC Premium Member Join Date: Aug 2006 Location: Winnipeg, Canada Posts: 217	The point is moot for me anyways now. I ended up getting an Aqua 114w UV and let the twists/turns be damned. Bigger wattage makes more sense then steps or twists to me.

11/19/2006, 10:37 AM	#12
gabe3d Registered Member Join Date: Oct 2003 Location: Elk Grove/Sunnyvale/Shibuya Posts: 1,605	The amount of water already inside of the Sterilizer needs to be accounted for so lets say your UV sterilizer is 100 gallon in size and you are pushing 50gph for argument sake. The water that has just entered the unit will not exist until the 2 hours has elapsed. Now lets say you sterilizer is only 50 gallon in size, the water that has entered will exit after 1 hour. The coil or stepping system does help make the exposre time longer.