UV Light Question

[wilddiscuss]

I have decided to add a UV light to my discus show tank. I don't know much about them accept that The water runs through the light ect. My qusetion is can I run it on the same line as the trickle filter return line? I also have a cannister filter. Can I run that as well on the same line as a trickle? Or is that over kill? Or just flat out not possible? Thanks again to all. This web site has be a great help.

Todd

[tonymaccs]

The flow rate of your return line needs to match the design flow rate of the UV you choose if you want to put it in series with your filtration.
Regarding linked filters, you could theoretically do anything as long as the hydraulics works (flow rates, head, etc) but as canisters are made to run independently do it this way as you then have one acting as a back-up if anything goes wrong with the other.

[Clyde]

UV filters have max and min flow. Flow greater then the maximum and it will not be effective. Flow less then the minimum and the bulb will over heat and crack.


Mark

[Troy Williams]

Todd, i used a 12w uv light on my fluval 305 canister. It worked really well, no algae etc. Flow rate was spot on with no heat felt on the casing when at maximun flow. HTH

Troy.

[FishLover888]

It depends on what you want your UV to do.

To kill algae, you can have it running at much higher rate. To kill other nasty things in your tank, you can run at a lower speed. In general, you need to at least turn your tank water thrugh UV every hour. That way the UV can kill as fast as the repreduction rate of whatever you want to kill.

Say you have a 100g tank, you need the pump to be at least 120gph. Maybe a bit more factor in the water have to turn in different direction in order to pass the UV tube. Then you can decide the size of the UV depending on what you like to kill. I would go for about 24 to 30w if I'm going to kill other nasty things. If only for algae, maybe a 12 W is good enough.

You need to run the UV 24x7 and replace the light bulb every 6 to 9 months.

[wilddiscuss]

It depends on what you want your UV to do.

To kill algae, you can have it running at much higher rate. To kill other nasty things in your tank, you can run at a lower speed. In general, you need to at least turn your tank water thrugh UV every hour. That way the UV can kill as fast as the repreduction rate of whatever you want to kill.

Say you have a 100g tank, you need the pump to be at least 120gph. Maybe a bit more factor in the water have to turn in different direction in order to pass the UV tube. Then you can decide the size of the UV depending on what you like to kill. I would go for about 24 to 30w if I'm going to kill other nasty things. If only for algae, maybe a 12 W is good enough.

You need to run the UV 24x7 and replace the light bulb every 6 to 9 months.

Thanks :) That helps. I do want to run it to kill Parasites and viruses, as well as algae. Will this also ruin any of the good bacteria for my trickle filter? I would hope not. Has anyone that runs a UV light had any problem like that?

Todd

[tonymaccs]

UV only affects organisms that are exposed to the light - degree of effectiveness determined by UV wavelength, intensity of light, and exposure time.
So it has nil effect on your trickle filter unless you can manage to get the light into the filter.

[wilddiscuss]

UV only affects organisms that are exposed to the light - degree of effectiveness determined by UV wavelength, intensity of light, and exposure time.
So it has nil effect on your trickle filter unless you can manage to get the light into the filter.

Thanks :) Ok well I am going to get one. Anyone have any suggestions on a good brand and where I can get it?

[Cosmo]

The Coral Life twist series are good, modestly priced, and very easy to install. The Pentair Aquatics are good lights, but a REAL PITA to install.

I run both, the Coral Life 18 watt on a 90 gal and a P.A. 25 watt on my 180. Both are plumbed into the return lines of Magnum 350's which I use only for mechanical filtration.

As I recall, to kill virus's you need a pretty high output UV, and they can get pricey.

If you run the light on a filter return line, make sure you set it up so that you don't inadvertantly turn off the filter (for cleaning etc) but leave the light on... I literally melted the plastic housing of one a few years ago this way.

In order to prevent that from re-occuring I now plug both the UV and the pump (cannister) into a dedicated power strip. When it's time to clean the cannister I turn off the power strip to kill power to both. Also handy if you want to run the UV/pump less than 24/7 as one timer will turn both on/off at the same time.

Jim

[phidelt85]

I've got my Pentair uv8 running off a slipstream on my sump return line.

[tonymaccs]

I have a Cloverleaf Stainless Steel Smartstart 48w. I has twin bulbs with integrated ballast (more energy efficient and longer life). It will handle flows up to 8000 litres/hr. Bit of an overkill and it's about 3ft 6in long, but it didnt cost all that much more than the much smaller ones and I know it will do the job.

[Apistomaster]

I have a Cloverleaf Stainless Steel Smartstart 48w. I has twin bulbs with integrated ballast (more energy efficient and longer life). It will handle flows up to 8000 litres/hr. Bit of an overkill and it's about 3ft 6in long, but it didnt cost all that much more than the much smaller ones and I know it will do the job.
Hi Tonymaccs,
I don't think what you are running is over kill at all. Most manufacturers grossly over estimate the sterilizing ability of their units.
There are several good reasons to use the largest unit you can afford.
1. Higher wattage units are more effective.
2. The length of useful life is extended if the unit is "oversized" as the lamp out put drops considerably by six or eight months so the higher powered over sized unit will be useful longer before a lamp change is required.
3. The intensity should be about 30,000 microwattsecond/cm2 for truly effective germicidal effects and the dwell time should be as long as is practically possible. This is several times more than manufactures would have us believe. The flow through the UV unit should be just enough to prevent overheating the UV unit.
It is best to divert flow from either the wet/dry or canister(makes no difference which) with a ball valve incorporated into the plumbing so one has infinite control over the rate of flow through the UV unit and the sterile water is then returned to the return line.

[Ed13]

I completely agree with Larry on the specs, UV units are usefull and do work but manufactures do overestimate the capabilities by a mile an a half.
And it is best to divert flow from either the wet/dry or canister with a ball valve

[wilddiscuss]

So Basically I should get a High as possible watt UV light and slow the flow rate down from my return on my trickle filter with a valve so the flow is slow as it passes through the bulb. What watt does everyone suggest for a 75 gallon? I will check on some of the brands that have already been suggested. Thanks again :)

Todd

[tonymaccs]

Larry, My thoughts exactly, but even the supplier thought I was crazy buying what he thought was too big a unit.
I've come accross many people who have come to the opinion that UV is a waste of time and wonder how much that has to do with poorly designed, undersized applications.
One of the reasons I bought the Cloverleaf is that when I come to replace the lamps I can choose to upgrade to 72Watts as the unit is common to both.
Tony

[Apistomaster]

Hi Tony,
The suppliers are suffering from salesmen snow job syndrome.

The way to calculate what is enough for professional grade UV sterilization is something I do not know how to do. It really can be complicated.
I would ask your UV manufacturer to tell you what flow rate through your unit will provide a minimum of 30,000 microwatt/s/cm2. They should be able to answer you off the top of their heads. (They have charts or software that will render an instant solution.) Just don't tell them its for your discus tank but rather for your quarantine tank and just give them the size of your discus tank as the basis for their calculations. Tell them you require the above UV level intensity, period.
I forgot to add that you want to know what it will take to have that intensity six to nine months out. The real working life.