UV operation?

[Kbra]

I plan to run my UV 24/7 in line with my system return. I'd prefer to not switch the bulb on and off when the return turns of for feeding cycles. Is it ok to leave the bulb on with no water flow through it? Basically is the water important for cooling or something? It would only be for like 10 min once a day...

 

[nahtanoj]

i doubt it would be an issue. those bulbs don't run very hot.

 

[Kbra]

Also another idea ive been pondering.
Im thinking about running my 1.5" overflow drain into my 2" UV and then into the sump.
Im looking for any reasons or ideas why this may be a bad idea.

The UV is a Aqua UV 25w w/ wiper
The idea is to eliminate the need for another pump and to minimize clutter in sump area.

 

[Kbra]

bumpn for inputs

 

[coral diver]

I run mine at the same time as the main light.

 

[Kbra]

Im talking about actually pluming it in to the drain to the sump. not timing

Ill take some pics to better explain

 

[coral diver]

mine is a 15w it draws from the drain chamber of the sump and drain at the return side of the sump, the flow has to be slow to be affective.

 

[MechaSamurai]

Just a thought, but it seams like it would be safer to run it on the return just in case it ever plugs up or restricts flow. If you ran your tank near the top and the drain line was plugged would your display be able to hold the extra water from your sump?

 

[Kbra]

My reasoning behind not doing the return is that i still have a small chaeto setup in my sump for pods and such and anything coming from the sump would be dead instantly. I know my UV will kill any that pass through the water column but not all of them will pass through the overflow... It would be a close call if the drain clogged but the return chamber is fairly small in resepect to the surface area of the tank and should be ok with the sump setup. Plus its gonna be hard to clog a 2" pipe...

 

[Kbra]

Ok so heres the current setup. The black pipe is my drain from overflow going from right to left.

Then i would cut out the straight portion and insert this UV. There will be 2x 1.5" 90s added to the system. Flow wise its already too fast and has to be controlled down with a ball valve so shouldnt be an issue. Ill probably use sweeping ones too.

Crappy pics but i think it a get the idea out there better

I appreciate any criticism on this idea, im looking for anything i didn't think of to be a problem.

 

[MechaSamurai]

Doesn't your drain line empty out once the return pump is off? Most of the water would probably drain right out and leave the sterilizer relatively dry; you could make it with something like a goose neck (sink trap) but even then you may get a siphon going that would suck out the water (like a toilet flushing).

If your main goal is to avoid another pump is there any reasonable way to attach it to your skimmer?

 

[Kbra]

Yeah that was the bases of my first question. Cause it will run dry for like 10 min a day for feedings and stuff like that but i dont know how crucial it is for the UV to constantly have water flowing. Like some one mentioned it runs fairly cool so 10 min on with no flow 'should' be ok... I can always have the controller turn off the UV when the return is off but im trying to avoid any switching and just leave it on.... Its the AQUA UV 25w it supports up to 1200gph as a sterilizer
http://www.marinedepot.com/ps_ViewI...AV2203&tab=0&style=with wiper&size=25 watt 2"

 

[nahtanoj]

at that rate it will not kill ich. it will only handle basic bacteria and algae.
a general rule for UV to handle ich is 100gph per 40w. that puts your 25w in the range of 50-60gph to kill ich. i will post some links up when i get home on organisms required UV exposure.

 

[Kbra]

I found this link with the specs for Aqua UV
http://www.aquaultraviolet.com/sites/default/files/brochures/UV Charts Salt and Fresh Water.pdf

 

[nahtanoj]

http://www.tmc-ltd.co.uk/data/bacteria.asp

this gives kill rates. ich is 336,000 μw/cm².
so with your unit the required flow is 107gph to kill ich.

 

[Kbra]

wow ich is off the charts to kill!

 

[nahtanoj]

yep, very few people that are running UV run it appropriately to kill ich.

 

[Kbra]

thats also for a 99.9% kill rate... basically one pass kills all but the idea is to filter your entire system multiple times per hour... at the same time u dont have to do it multiple times if the first time does the trick

 

[Novaculichthys Taeniourus]

You should never let the UV run dry for more than a very short period of time as you will risk cracking the quartz sleeve. At the very least you will increase drastically increase the amount of mineral deposit on the sleeve as it drys each time.

 

[nahtanoj]

the 99.9% is there safety measure to not get sued. it is either dead, or not dead. to make it dead you need 336,000 μw/cm². for it to work properly you need to buy a high enough wattage to cycle your tank several times a day.