UV sterilizer on the drain line?

[Raul-7]

Since the flowrates in the return are really high, why not have the UV on the drain line since it's much slower to ensure pathogens are eradicated not only algae?

[wooden_reefer]

The uv needs a bypass or a separate small pump, otherwise too fast.

[Raul-7]

The drain is gravity fed. How would it be too fast?

[sowildpaul]

It's recommended that the water which goes into UV is filtered to avoid detritus build-up inside it.

[jimmyj7090]

Originally Posted by Raul-7

Since the flowrates in the return are really high, why not have the UV on the drain line since it's much slower to ensure pathogens are eradicated not only algae?

The flow in the (single) drain line is exactly the same as the flow rate through the return (single). Pump up, gravity down, exact same volume.

[Mark426]

Is UV actually effective?

[jrp1588]

Originally Posted by jimmyj7090

The flow in the (single) drain line is exactly the same as the flow rate through the return (single). Pump up, gravity down, exact same volume.

This. They are both the same. Otherwise your pump would outpace your overflow and you'd get a flood.

[slief]

UV filters bulbs are cooled to an extent by the water. Since water coming from the drain typically has air bubbles in it, it's possible that the bulbs would run hotter than desired and may experience a shorter lifespan. The UV filter should remain completely flooded at all times without any presence of air. Additionally, the air bubbles in the water would impact the UV's effectiveness. Somebody mentioned detritus which is also a consideration. By running it on the drain line, you are most certainly going to accumulate debris inside the UV which will impact it's effectiveness and also increase maintenance.

As for too much flow, that would be dependant on the UV filter used. Different UV filters have different flow ratings. Some are designed to maximize contact time at higher flow rates while others. especially cheap ones need really slow flow to be effective. Additionally, UV filters can be used for different things and much of that use is predicated on flow rates. All filters have a scale that ranges from water polishing at higher flow ranges vs sterilization at lower flow rates. When implementing a UV filter, one must decide what the goal is for it. Are you implementing it for water clarity or are you implementing it for parasite control. At the really low flow ranges pods and other useful life are effected so mody reefers who understand the use of UV filtration try to find a happy medium between water polishing and parasite control. As such, we often tend to err on the mid to higher flow range of the filter.

I use an Aqua UV Classic 114 watt unit which is a very effective unit at higher flow ranges. I chose that unit because of features and flow.. It was a very good fit for my system and it's very effective for my primary use which is water polishing. I run mine in the mid range of the units flow capabilities. If I shut it off for an extended period of time, when I turn it back on, the difference in water clarity is noticeable within 24 hours despite the use of filter socks and carbon.

[Wryknow]

The biggest issue that I see is the size of the drain line. UV sterilizers are usually sized with realtively narrow tubing inside them. If it's narrower than the drain line then you'll be restricting the drain capacity. It may or may not be a problem for you depending on the set up but I thought I'd mention it.

[slief]

Originally Posted by Wryknow

The biggest issue that I see is the size of the drain line. UV sterilizers are usually sized with realtively narrow tubing inside them. If it's narrower than the drain line then you'll be restricting the drain capacity. It may or may not be a problem for you depending on the set up but I thought I'd mention it.

My Aqua UV unit has 2" inlets and outlets. That is an option on all of their Classic models. The other option is 3/4" but again, their units are not like many of the cheap units out there. That said, you do bring up a very good point in that having any kind of obstruction on the drain line is asking for problems. Even though this unit has 2" inlet/outlet, the crystal sleeve in addition to the fittings and elbows will restrict flow and that can cause issues. Not a good choice for a UV filter location at all and I would never condone it.

[wooden_reefer]

Originally Posted by Raul-7

The drain is gravity fed. How would it be too fast?

Typically, if all the water of the "open loop" goes thru the UV, then it is likely too fast.

Unless you in essense have a bypass; that is excess water in the open loop does not go thru the UV.

You are using the friction of the UV to dictate the flow and then allow water bypass. One leg goes thru the UV then the sump; the other to the sump directly. I guess this could work. Experiment with the relative friction of the two legs or add a valve on the UV leg to regulate.

A valve on the leg of the UV is likely needed to shut off during servicing of the UV.

[wooden_reefer]

Originally Posted by slief

UV filters bulbs are cooled to an extent by the water. Since water coming from the drain typically has air bubbles in it, it's possible that the bulbs would run hotter than desired and may experience a shorter lifespan. The UV filter should remain completely flooded at all times without any presence of air. Additionally, the air bubbles in the water would impact the UV's effectiveness. Somebody mentioned detritus which is also a consideration. By running it on the drain line, you are most certainly going to accumulate debris inside the UV which will impact it's effectiveness and also increase maintenance.

As for too much flow, that would be dependant on the UV filter used. Different UV filters have different flow ratings. Some are designed to maximize contact time at higher flow rates while others. especially cheap ones need really slow flow to be effective. Additionally, UV filters can be used for different things and much of that use is predicated on flow rates. All filters have a scale that ranges from water polishing at higher flow ranges vs sterilization at lower flow rates. When implementing a UV filter, one must decide what the goal is for it. Are you implementing it for water clarity or are you implementing it for parasite control. At the really low flow ranges pods and other useful life are effected so mody reefers who understand the use of UV filtration try to find a happy medium between water polishing and parasite control. As such, we often tend to err on the mid to higher flow range of the filter.

I use an Aqua UV Classic 114 watt unit which is a very effective unit at higher flow ranges. I chose that unit because of features and flow.. It was a very good fit for my system and it's very effective for my primary use which is water polishing. I run mine in the mid range of the units flow capabilities. If I shut it off for an extended period of time, when I turn it back on, the difference in water clarity is noticeable within 24 hours despite the use of filter socks and carbon.

The UV with quartz is more effective. One reason could be just that the lamp runs hotter and more shorter wavelength rays are emitted.

The air bubbles can be a problem.

Most people do not have 114 watt UV unless the tank is quite large.

[wooden_reefer]

I think with a supersized UV, even ich may be reduced or contained, but not eradicated.

Would a 114 watt UV overheat a small tank in the summer?

[wooden_reefer]

Originally Posted by Mark426

Is UV actually effective?

Yes, when the flowrate is low enough it kills waterborne bacteria and algae well.

External bacterial infection for fish is much reduced.

[slief]

Originally Posted by wooden_reefer

The UV with quartz is more effective. One reason could be just that the lamp runs hotter and more shorter wavelength rays are emitted.

The air bubbles can be a problem.

Most people do not have 114 watt UV unless the tank is quite large.

I would never condone the use a UV without a quartz sleeve and any quality UV has a quartz sleeve. That said, all AquaUV sterilizers include the quartz sleeve and all AquaUV Classic models from their 8 watt unit to their 240 watt model are available with 2" fittings as they all have a 2" diameter body. The AquaUV Classic units unlike typical sterilizers are capable of sterilization at higher flow rates although each unit based on wattage has specific operational ranges depending on what you want to accomplish. High flow is obviously relative to tank size.
With an 8 watt AquaUV Classic Sterilization occurs at 214 GPH and gradually shifts to polishing at rates up to 642 GPH..

For reference, here are some flow rates for the 8 Watt Classic model which is good for up to a 70 gallon salt water tank.
30,000 µw/cm2 (EOL) 642 gph 75,000 µw/cm2 (EOL) 256 gph
45,000 µw/cm2 (EOL) 428 gph 90,000 µw/cm2 (EOL) 214 gph
60,000 µw/cm2 (EOL) 321 gph

Here is their 15 watt specs which is good to 75 gallons.
30,000 µw/cm2 (EOL) 700 gph 75,000 µw/cm2 (EOL) 280 gph
45,000 µw/cm2 (EOL) 466 gph 90,000 µw/cm2 (EOL) 233 gph
60,000 µw/cm2 (EOL) 350 gph

Here is the 114 Watt Classic specs which is good for up to a 700 gallon system. This unit fit my tank size and my flow requirements based on my recirculation pump and desired effects from the UV unit.
30,000 µw/cm2 (EOL) 3,900 gph 75,000 µw/cm2 (EOL) 1,560 gph
45,000 µw/cm2 (EOL) 2,600 gph 90,000 µw/cm2 (EOL) 1,300 gph
60,000 µw/cm2 (EOL) 1,950 gph

Obviously, properly sizing and setting up a UV sterilizer has as much to do with flow rates as it does wattage per gallon so choosing the right make, model and wattage for ones needs isn't as simple as just considering the total water volume.

Despite the presence of a quartz sleeve shielding the bulbs from water, the water passing around the sleeve has a cooling effect on the bulb as it reduces the ambient temperature inside the sleeve. As such, any air inside the body of the UV filter will impact not only cooling and longevity of the bulb but it will also degrade the effectiveness of the sterilizer.

[sowildpaul]

Originally Posted by slief

I would never condone the use a UV without a quartz sleeve and any quality UV has a quartz sleeve. That said, all AquaUV sterilizers include the quartz sleeve and all AquaUV Classic models from their 8 watt unit to their 240 watt model are available with 2" fittings as they all have a 2" diameter body. The AquaUV Classic units unlike typical sterilizers are capable of sterilization at higher flow rates although each unit based on wattage has specific operational ranges depending on what you want to accomplish. High flow is obviously relative to tank size.
With an 8 watt AquaUV Classic Sterilization occurs at 214 GPH and gradually shifts to polishing at rates up to 642 GPH..

Wondering if you installed a flow switch on your UV's return line or not. A chiller needs one, too if it's not built in the unit as heat pumps w/cooling mode do have one built-in. IMO, all UV units should have a built-in flow switch to prevent damage and for safety purpose.

[slief]

Originally Posted by sowildpaul

Wondering if you installed a flow switch on your UV's return line or not. A chiller needs one, too if it's not built in the unit as heat pumps w/cooling mode do have one built-in. IMO, all UV units should have a built-in flow switch to prevent damage and for safety purpose.

I am not sure what you are talking about with regards to a flow switch.. Are you suggesting some kind of switch that turns them off should the flow stop?
If so, I've never run one and really don't think that is needed. If you run a controller like an Apex, you can add that to the UV outlet programming in the event that you physically turn a pump off
"If Pump OFF then OFF".

In 25 years of running chillers and UV's, I've never run a flow switch and never once had an issue. Most chillers have the thermostat temp sensor inside the chillers cooling tank. If the temp gets too cold in the chiller than the chiller will turn off. In the case of an external thermostat where the temp probe is in the sump, than I suppose that could be an issue however, we as aquarists pay close attention to our tanks and should a pump stop working, we will have bigger issues. A flow sensor would likely compromise flow anyway and I really don't think there is a need for it. The only instance I can see this being even remotely relevant would be in the event of a pump failure and not paying enough attention to catch the problem. Even then, with the UV filter completely filled with water, the damage to the bulbs from heat build up would take days as opposed to hours. As for a chiller, worse case, the tank freezes and you have to thaw it out. I've never seen a chiller tank crack as a result of freezing water although that could happen in rare instances.

For reference, here is how my UV is plumbed in. I feed it with a Reeflo Dart recirculation pump. The output side of the dart is restricted though my plumbing going into the tank. This particular pump dumps out below the rock work through a PVC manifold that circles my overflow under the rocks. While there are dozens of holes in the manifold to allow water out of the manifold, there is a fair amount of head pressure or restriction created which really restricts the flow. I'd guess I am running around 200GPH through it. I have valves in line so if I need to deal with parasites, I can slow it down but I don't ever really have those issues.

[sowildpaul]

Originally Posted by slief

I am not sure what you are talking about with regards to a flow switch.. Are you suggesting some kind of switch that turns them off should the flow stop?
If so, I've never run one and really don't think that is needed. If you run a controller like an Apex, you can add that to the UV outlet programming in the event that you physically turn a pump off
"If Pump OFF then OFF".

In 25 years of running chillers and UV's, I've never run a flow switch and never once had an issue. Most chillers have the thermostat temp sensor inside the chillers cooling tank. If the temp gets too cold in the chiller than the chiller will turn off. In the case of an external thermostat where the temp probe is in the sump, than I suppose that could be an issue however, we as aquarists pay close attention to our tanks and should a pump stop working, we will have bigger issues. A flow sensor would likely compromise flow anyway and I really don't think there is a need for it. The only instance I can see this being even remotely relevant would be in the event of a pump failure and not paying enough attention to catch the problem. Even then, with the UV filter completely filled with water, the damage to the bulbs from heat build up would take days as opposed to hours. As for a chiller, worse case, the tank freezes and you have to thaw it out. I've never seen a chiller tank crack as a result of freezing water although that could happen in rare instances.

Yeah, I was talking about this one, http://www.marinedepot.com/Aqua_Logi...FICHCA-vi.html

[slief]

Originally Posted by sowildpaul

Yeah, I was talking about this one, http://www.marinedepot.com/Aqua_Logi...FICHCA-vi.html

Interesting.. Been at this a lot of years and never seen one of those. Probably because it's not something I ever felt I needed and therefor never looked. Those certainly could have applications for some. Thanks for pointing it out.

[kinnadian]

Originally Posted by wooden_reefer

Yes, when the flowrate is low enough it kills waterborne bacteria and algae well.

External bacterial infection for fish is much reduced.

Algae in the water column is proportionally very low compared to algae on rocks/glass/etc. Killing the algae in the water column does very little, algae doesn't really grow in the water it grows on a surface. The exception to this is of course green water, where a UV steriliser IS recommended.

Killing bacteria in the water column will do more harm than good.

UV can lower bacterial infections (eg ich) for fish, but it will NOT eradicate or even make a sizable difference. It can aid treatment but certainly not eliminate it. You are better off using the money you saved in not buying a waste of time UV steriliser, and putting it towards a Quarantine tank so you never introduce bacterial infections in the first place.

UV steriliser is the absolute last thing I would EVER buy for any marine setup. It has the lowest returns on the cost of anything.

[wooden_reefer]

Originally Posted by kinnadian

Algae in the water column is proportionally very low compared to algae on rocks/glass/etc. Killing the algae in the water column does very little, algae doesn't really grow in the water it grows on a surface. The exception to this is of course green water, where a UV steriliser IS recommended.

Killing bacteria in the water column will do more harm than good.

UV can lower bacterial infections (eg ich) for fish, but it will NOT eradicate or even make a sizable difference. It can aid treatment but certainly not eliminate it. You are better off using the money you saved in not buying a waste of time UV steriliser, and putting it towards a Quarantine tank so you never introduce bacterial infections in the first place.

UV steriliser is the absolute last thing I would EVER buy for any marine setup. It has the lowest returns on the cost of anything.

The uv is very useful in reducing the incidents and severity of external bacterial infection.

Before exposure and antibodies, Fish has general defense like WBC but the capacity is quite limited.

Before antibodies, the concentration of waterborne pathogenic bacteria should be kept low.

I think a properly set up uv lowers incidents of bacterial infection, IME may be 70 percent.

Ich is not bacterial and uv sized for bacterial does not impact ich.

I feel naked without uv during the first weeks of new fish before exposure and antibodies.

[Reef Frog]

I've always wondered whether a tank with the best possible UV set up could help eradicate or significantly reduce Bubble Algae when used during a long period of simultaneous and relentless physical removal? Let's assume nutrients are low, no Emeralds, prudent feeding, fresh bulbs etc.

You always read about how Bubble Algae releases "spores" when disturbed or removed, explaining why it seems to pop up in the most unlikely places. I don't know if this is how it actually reproduces or all that much about its actual life cycle & natural environment. But it sure sounds plausible to me. It seems it could "zap" these water born spores in numbers significant enough to really slow it down. After all we know for a fact that it clears the floating micro algae that makes water green. Can it disrupt the reproductive cycle?

So does anyone have info or real life experience using a really high end UV system to cobalt bubble Algae?

[wooden_reefer]

Originally Posted by Reef Frog

So does anyone have info or real life experience using a really high end UV system to cobalt bubble Algae?

Likely the effectiveness of UV is decided by path or length of exposure within the UV, whether it has quartz, and the wattage.

Otherwise high end or not may affect durability and safety than effectiveness.

Some people are very much into brands.

The manufacturer can cite any max effective flow rate, but what is the proof of effectivenss at that flow rate?