plumbing a fuge and u/v unit

[ynotme4886]

I am converting over to an under the tank fuge instead of a wet dry and my hob fuges.
I want to plumb my u/v unit as easily as possible and am trying to save space.
I don't want to run the u/v through the return line from the new refugium because I am afraid that any living critters will get fried by it.
My question is this... My skimmer is powered by a mag 9.5 that is slightly retarded (the valve isn't completely open....overdriving the skimmer) This works great and I skim a ton of crap but can I run my lines as follows. mag 9.5 then the u/v and then into the skimmer. Then the water would flow into the 2nd chamber of the fuge. It shouldn't kill any of the critters that way and I won't need a separate pump for the u/v thus saving electricity and the heat from another pump.
Has anyone done this and will it affect my skimmer in any way?
Thanks

 

[salt210]

the UV will slow down your flow. also the UV might possibly be rated for less flow than the Mag

 

[ynotme4886]

I'm gonna buy a bigger u/v so the I can match up the minimum flow with the size of the u/v The u/v I have now is too small for my current tank.... but a small u/v was all I had when I set it up.
My skimmer needs a mag 7 but can be overdriven with a mag 9.5. I had to put a valve on the feed line between the pump and the skimmer (recommended by the manufacturer ) cause the mag 9.5 at full pressure was too much.
So I still have a bit of flow to play with and can open the valve a bit more to make up for the added u/v in the way.
Is it worth trying this or am I just asking for problems.

 

[sly]

The Mag 9.5 is rated for 950 gph. Even with the flow reduced you would need an enormous UV light for it to have any effect on free floating protozoa (which is what you want to kill when running UV). Also, the UV light needs the cleanest water possible. This means that it needs to draw water from the last stage of your filter system. The chamber that you put your return pump is where I would put your UV pump... and yes, the UV needs its own pump.
I have an 18 watt UV light on my 72 gallon tank. I use a very small pump that only delivers 100gph of water flow. I then reduce the flow with a shutoff valve until it's about 80gph. This is about right for my tank. I plumbed an inline flowmeter to check the flow to make sure that it stays at 80gph. The whole system consists of the UV pump drawing in clean water from the last chamber, passing through a shutoff valve, through the UV light, then the flowmeter and then back into the sump. It has to be on its own loop in order to be effective. Like I said, the pump needs to be in the last chamber because any contaminates in the water will cloud the water as it passes through the UV, reducing the effectiveness. This means that it needs to be after your skimmer... The water needs to be as clear as possible to kill the organisms you are looking for. I have run UV for several years and have a very healthy pod population that feeds my mandarin. The coral is growing like crazy too.
Before we can determine if your setup is even going to work we need to know your tank size and the wattage of your UV. Updating your profile would help...

 

[ynotme4886]

Sorry.... have a 92 corner rr with a 20 gal fuge and am thinking about a 36w u/v unit
1st chamber is sump buddy 40 powered by the mag 9.5 and the return pump is a mag 7
Middle is going to be sand, rubble and macro all taken out of the 2 hang on fuges that I currently use (they are full of critters as well)
Tank has about 150lbs of live rock give or take a few lbs and is fish inverts and anemone only.... not a reef.
Other than that... nothing fancy....

 

[salt210]

you don't need a UV that big. I have a 25watt and its rated for 1200gph

 

[sly]

Originally Posted by salt210
http:///forum/post/2724602
you don't need a UV that big. I have a 25watt and its rated for 1200gph

Code:
[pre]Model Watts Max. Aquarium
(gal) Max. Pond
(gal) No.
Lamps Algae & Common Bacteria
30,000UW-Sec/Cm2 Protozoa 90,000UW-Sec/Cm2
02012 12 50 600 1/12 *5.44 gpm *1.80 gpm
02018 18 70 900 1/18 *8.38 gpm *2.79 gpm
02025 25 125 1400 1/25 *13.14 gpm *4.38 gpm
02040 40 200 2800 1/40 *26.24 gpm *8.75 gpm
02065 65 400 5000 1/65 *47.59 gpm *15.86 gpm
02080 80 400 5600 2/40 *52.47 gpm *17.49gpm
02130 130 700 10000 2/65 *95.19 gpm *31.73 gpm[/pre]

 

[sly]

Originally Posted by salt210
http:///forum/post/2724602
you don't need a UV that big. I have a 25watt and its rated for 1200gph
Actually that is not true. Whenever manufacturers list information like this, it simply refers to the amount of water that can possibly travel through the unit when used on an outdoor pond. If you are actually wanting to use the sterilizer to kill algae or better yet, protozoa, then you need significantly less water flow. Algae and protozoa need a very high exposure time under UV before they will be killed. 1200GPH would be good if you wanted to use the UV light on a pond just to reduce the amount of algae, but that amount of flow would be totally ineffective when used in an aquarium which demands a much higher water quality.

• Typical UV light performances

As you can see from the chart, for a typical 25 watt UV light you can have a maximum 13.14GPM of water flow or 788.4GPH if you want to kill free floating algae. If you want to kill the more difficult protozoa then the water flow is reduced to 4.38GPM or 262.8GPH... In other words for your 25 watt UV light, you can have only a 262.3GPH flow through the unit before it becomes ineffective at sterilizing the water.
Typically you want at least a 2 times tank turnover through the UV per hour. A 2 times tank turnover will sterilize 90% of the water. Higher turnover rates do not provide much more sterilization than this... So if you have a 92 gallon tank plus a 20 gallon fuge, you need at least 224GPH of water flow (112 gallons x 2) through the UV light. Going by the chart that would mean that the OP needs around 25 watts of UV to effectively sterilize the tank. (25 watt= 4.38gpm or 262.8gph). A 36 watt UV light that the OP is suggesting would work fine and would allow for further expansion but a 25 watt unit would be good enough for the current system. I would probably use a 25 watt or bigger unit and set the water flow to around 224gph.

 

[ynotme4886]

I wanted to go with a big u/v only for the fact that I know I will be going larger in tank size again. I currently only have a 9w on this tank and it is run through my canister return line and is definitely undersized.
So by looking at the chart it makes a lot of sense. I should run a separate pump on a closed loop in my last chamber of my sump for the u/v or I could run it on a powerhead through a hang on type setup.
When calculating the amount of flow, should I use the total tank volume (tank and sump) for doing the math? I assume I would.
Also how often would you change the bulb out?
Thanks for the help Sly

 

[sly]

Yes, you should put it on its own loop seperate from everything else. It needs to be after the skimmer because the water needs to be a clean as possible before it enters the UV light. Buy a flowmeter to be sure you are maintaining the proper flow through the unit... Over time a pump can reduce flow and so you need to be able to check it so that you can make the necessary adjustments.
The total tank volume would be the volume of your tank, refugium and sump added together. You want to clean the entire water column and so you want to include any water that is plumbed into the system. I would change out the bulb once every year or sooner. They don't really burn out but UV bulbs change spectrum dramatically as they age and so when they age they are no longer putting out the correct UV spectrum to sterilize your tank.
I've run UV for about 6 years and have had no problems with it. I have healthy coral, an anemone, feather dusters and a hard to keep mandarin goby and the UV hasn't negatively impacted them as far as I can see.... They are all still growing. I've also never had a disease outbreak in my tank and I don't have any algae other than what's growing in the fuge... So I would definitely recommend a UV light. IMO it can only help.

 

[sly]

Note that I corrected the math for the above post to include the size of the fuge...

 

[hillk]

i have been running a fuge/ chaeto on a 90 softie tank with 6 fish etc, tunze skimmer with a biohome [cintered glass] chamber for years with no problems UV will kill the pods going back to the tank IMO

 

[sly]

Originally Posted by hillk
http:///forum/post/2726674
UV will kill the pods going back to the tank IMO
That's funny... it hasn't seemed to kill the hundreds of pods in my tank that feed my goby. If you plumb the UV through your main pump then you might be right... but UV is designed to be on its own loop. Most of the pods will bypass the UV and go straight to the tank since the UV is only pulling 2 cycles per hour.