UV - best turned off at night? - Koi Forum - Koi-Bito Magazine

kiky · 06-06-2006

In a recent gathering among hobbyists, one friend of mine said that UV should be switched on only when there is sunlight. In the dark it is best left turned off. Is there any truth to this? and why?

Also, there was a lively discussion as to where is the best place to place the UV? Is it in the last chamber, or the 1st vortex? If I remember correctly, Maeda San of Momotaro has once advice putting the UV in the 1st chamber, even though most of us put it in the last chamber. Please comment on this, thank you.

Russell Peters · 06-06-2006

If you turn your UV light on and off everyday, the bulbs will burn out faster. This seems to be the worst effect of doing this. There is really no point in turning it off. I don't really think it matters where you put it in your filter system, but I install them last.

morris · 06-06-2006

don't shut it down r will you have mud pool????????

keokoi · 06-06-2006

Ok to add another twist.. When is the best time to start a UV on a brand New pond.. New water pond filters etc?

Joe

Mike T · 06-07-2006

Joe:

When I installed our first pond, I left the UV off for about a couple of months because I was too busy with other pond projects... A neighbor came over and mentioned that the water looked a little green... I installed the UV light and water cleared up...

When I installed our second pond, I installed the UV and turned it on when I filled the pond... Water stayed clear, and never had the slighest hit of green.

So from my experience, I don't think it makes a difference...

Aloha! Mike

Dale Torok · 06-07-2006

Russell Peters made a very good point about turning bulbs on and off shortening the life of the bulb. It happened to me.

Three years ago I installed two UV filters on my pond. I ran them 24/7 for two seasons except for turning them off during the winter months. The water stayed clear.

Last spring (start of the 3rd season for the bulbs), I started getting a tinge of green that continued to worsen. Then the water REALLY turned green. I bought new bulbs. The water cleared in about 10 days.

When I remarked to a friend that the bulbs were so darn expensive, he said, "Why don't you put them on a timer? 12 hours on during daylight and off 12 hours every night. That way the bulbs ought to last four years instead of only two."

It made sense to me, so that's what I did. Last year the UV bulbs were on 12 off 12 for the full season. The water stayed crystal clear. This spring, a few weeks after I turned the UV filters back on, the water started the green tinge thing and began to get worse. I could see where it was going, so the bulbs were replaced. I only got one season out of this set of bulbs.

Apparently, turning bulbs off and on every day puts much more wear and tear on them than simply leaving them on all the time.

Dale

Mike T · 06-07-2006

Dale:

You know that I love ya! So this post is tongue in cheek, sort of....

I have found that most all information and recommendations from manufacturers
is a heck of a lot more accurate than that of our well meaning friends, myself included!

It seems your post verifies this

Aloha! Mike

elunned · 06-07-2006

The UV is used to kill very very small single-cell suspended algea. The UV radiation damages the algea so that it clumps into particles that can be removed either in settlemt chambers or by filter matting. Healthy green algea passes through mechanical filtration where larger solids are removed.

For maximum efficiency, the UV light should be located after the solids settlement - that way suspended solids don't shield the algea and reduce the effectiveness of the UV radiation. I'm not sure on the timetable for how long it takes for the algea to clump after UV exposure. Taking the conservative approach, I would tend to place the UV after the last chamber, just to reduce the chance of fouling the biomedia with dead algea. Make sense?

Steve Nguyen · 06-07-2006

technically, the dealer/manuf. recommends to replace the bulb on yearly basis if you want optimal performance. haven't replace my yet after two years and it's still working fine so far.

in your case, have you clean the sleeve jacket? ( think that's what it's called) this should be done on yearly basis as well. I would say it should be cleaning every six months if the UV light is positioned on before the pre-filter or in first stage of filter or settling tank. if you put the UV light just before the water return to the pond, there will be less build up since the water already pass thru the filter media. remembers that algae won't be killed unless it exposes to UV lights. if there's a build up, not much UV light will expose. be careful when clean the sleeve jacket. it's very fragile.

Steve

Quote:

Originally Posted by Dale Torok

Russell Peters made a very good point about turning bulbs on and off shortening the life of the bulb. It happened to me.

Three years ago I installed two UV filters on my pond. I ran them 24/7 for two seasons except for turning them off during the winter months. The water stayed clear.

Last spring (start of the 3rd season for the bulbs), I started getting a tinge of green that continued to worsen. Then the water REALLY turned green. I bought new bulbs. The water cleared in about 10 days.

When I remarked to a friend that the bulbs were so darn expensive, he said, "Why don't you put them on a timer? 12 hours on during daylight and off 12 hours every night. That way the bulbs ought to last four years instead of only two."

It made sense to me, so that's what I did. Last year the UV bulbs were on 12 off 12 for the full season. The water stayed crystal clear. This spring, a few weeks after I turned the UV filters back on, the water started the green tinge thing and began to get worse. I could see where it was going, so the bulbs were replaced. I only got one season out of this set of bulbs.

Apparently, turning bulbs off and on every day puts much more wear and tear on them than simply leaving them on all the time.

Dale

kiky · 06-07-2006

Thanks for all the comments guys.

I think I should mention that the UV I am using is the fluorescent type, mostly used in Japan? I put it in the settling chamber, about 5 to 10cm above water level. It last for 6 months, when I replace it with new one. So far the result has been quite excellent.

06-06-2006	#1 (permalink)
kiky Sansai Join Date: Dec 2003 Location: indonesia Posts: 242	UV - best turned off at night? In a recent gathering among hobbyists, one friend of mine said that UV should be switched on only when there is sunlight. In the dark it is best left turned off. Is there any truth to this? and why? Also, there was a lively discussion as to where is the best place to place the UV? Is it in the last chamber, or the 1st vortex? If I remember correctly, Maeda San of Momotaro has once advice putting the UV in the 1st chamber, even though most of us put it in the last chamber. Please comment on this, thank you.

06-07-2006	#5 (permalink)
Mike T Tategoi Join Date: Mar 2004 Location: Pearl City, Oahu, Hawaii Posts: 429	Joe : From experience, I don't think it makes a difference Joe: When I installed our first pond, I left the UV off for about a couple of months because I was too busy with other pond projects... A neighbor came over and mentioned that the water looked a little green... I installed the UV light and water cleared up... When I installed our second pond, I installed the UV and turned it on when I filled the pond... Water stayed clear, and never had the slighest hit of green. So from my experience, I don't think it makes a difference... Aloha! Mike

06-07-2006	#8 (permalink)
elunned Nisai Join Date: Dec 2003 Location: St Louis, Missouri Posts: 78	placement of UV The UV is used to kill very very small single-cell suspended algea. The UV radiation damages the algea so that it clumps into particles that can be removed either in settlemt chambers or by filter matting. Healthy green algea passes through mechanical filtration where larger solids are removed. For maximum efficiency, the UV light should be located after the solids settlement - that way suspended solids don't shield the algea and reduce the effectiveness of the UV radiation. I'm not sure on the timetable for how long it takes for the algea to clump after UV exposure. Taking the conservative approach, I would tend to place the UV after the last chamber, just to reduce the chance of fouling the biomedia with dead algea. Make sense? __________________ Lynne in St. Louis

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06-06-2006	#2 (permalink)
Russell Peters Honmei Join Date: Sep 2005 Location: Martinez,CA Posts: 4,488	If you turn your UV light on and off everyday, the bulbs will burn out faster. This seems to be the worst effect of doing this. There is really no point in turning it off. I don't really think it matters where you put it in your filter system, but I install them last.

06-06-2006	#3 (permalink)
morris Fry Join Date: Jun 2006 Location: The Netherlands Posts: 7	don't shut it down r will you have mud pool????????

06-06-2006	#4 (permalink)
keokoi Honmei Join Date: Jan 2004 Posts: 2,684	Ok to add another twist.. When is the best time to start a UV on a brand New pond.. New water pond filters etc? Joe

06-07-2006	#6 (permalink)
Dale Torok Sansai Join Date: Jan 2004 Location: Lexington, KY Posts: 182	Russell Peters made a very good point about turning bulbs on and off shortening the life of the bulb. It happened to me. Three years ago I installed two UV filters on my pond. I ran them 24/7 for two seasons except for turning them off during the winter months. The water stayed clear. Last spring (start of the 3rd season for the bulbs), I started getting a tinge of green that continued to worsen. Then the water REALLY turned green. I bought new bulbs. The water cleared in about 10 days. When I remarked to a friend that the bulbs were so darn expensive, he said, "Why don't you put them on a timer? 12 hours on during daylight and off 12 hours every night. That way the bulbs ought to last four years instead of only two." It made sense to me, so that's what I did. Last year the UV bulbs were on 12 off 12 for the full season. The water stayed crystal clear. This spring, a few weeks after I turned the UV filters back on, the water started the green tinge thing and began to get worse. I could see where it was going, so the bulbs were replaced. I only got one season out of this set of bulbs. Apparently, turning bulbs off and on every day puts much more wear and tear on them than simply leaving them on all the time. Dale

06-07-2006	#7 (permalink)
Mike T Tategoi Join Date: Mar 2004 Location: Pearl City, Oahu, Hawaii Posts: 429	Dale: You know that I love ya! So this post is tongue in cheek, sort of.... I have found that most all information and recommendations from manufacturers is a heck of a lot more accurate than that of our well meaning friends, myself included! It seems your post verifies this Aloha! Mike

06-07-2006	#10 (permalink)
kiky Sansai Join Date: Dec 2003 Location: indonesia Posts: 242	Thanks for all the comments guys. I think I should mention that the UV I am using is the fluorescent type, mostly used in Japan? I put it in the settling chamber, about 5 to 10cm above water level. It last for 6 months, when I replace it with new one. So far the result has been quite excellent.