Optimum ODNO for a 75
Planted Tank Forums
Your Tanks Image Hosting *Tank Tracker * Plant Profiles Fish Profiles Planted Tank Guide Photo Gallery Articles

Go Back   The Planted Tank Forum > Specific Aspects of a Planted Tank > Lighting


Reply
 
Thread Tools Display Modes
Old 06-04-2006, 12:52 PM   #1
Peter
Algae Grower
 
PTrader: (0/0%)
Join Date: Apr 2005
Location: Norway
Posts: 17
Default

Optimum ODNO for a 75


Iím planning a 75 gallon tank and am thinking of going ODNO with T8s. Hereís my goal: Approach 3wpg (225 watts), T8s (because theyíre readily available and cheap), narrow (more room for a hood lid) and efficient. Iím wondering whether 2 T8 bulbs each on an Advance REL-4P32-SC (4xF32T8) ballast (already have one) to obtain 4x ODNO using individual reflectors is the way to go. Is my ODNO math right Ė ((4 x 32 watts x .88) x 2 ballasts) = roughly 225 watts? If Iím not on the right path, what are some suggestions out there to reach my goal? I'm DIY handy but, unfortunately, not technically minded.

Another question: Do I really need to build in a fan? For ventilation, can I get away with slats or holes in the sides and back of the hood? I plan on using glass (maybe an AGA Versatop - I have small kids) between the lights and the water. For aesthetic reasons I'ld like to keep the light from bleeding out from the front of the hood so I want to avoid stands.
Thanks,

Peter
Peter is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 06-04-2006, 02:19 PM   #2
gbhil
Planted Tank Obsessed
 
gbhil's Avatar
 
PTrader: (7/100%)
Join Date: Oct 2005
Location: Bunker Hill, WV
Posts: 346
Default

ODNO causes a bit more energy loss via heat. To compensate, adjust your calculation as follows:
(((4 x 32 watts x .88 ballast factor) x .75 heat loss factor) x 2 ballasts) = ~170 watts with 2 lamps or ~253 watts with 3 lamps.

I would use a 3 lamp setup and run the center lamp on a separate timer for a few hours a day.

A fan shouldn't be needed if you give adequate openings for ventilation, use long endcaps or spacers to allow airflow behind the lamps, and mount the ballasts in a separate enclosure. I'm running 4 ODNO4X T8's in an open back hood this way with no fan. It's hot, but no hotter than 4x65 watt PC lamps would be. I do recommend a glass cover(s) to lessen the evaporation. If your bulbs begin to 'pulse' or glow substantially less on the ends than in the center, then think about a fan.

HTH!
gbhil is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 02:58 PM   #3
darkfury18
Planted Member
 
PTrader: (22/100%)
Join Date: Apr 2006
Location: Tucson, AZ
Posts: 259
Default

From Shalu's measurements.. http://www.plantedtank.net/forums/li...-vs-light.html

You need 4 T-8 at 4x to achieve the 3wpg... that's because 4x gives 200% light output and roughly consumes 2x the power. T-8 are 32 watts so it'll take about 64 watts per bulb which means you'll need 4 of them
darkfury18 is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 03:26 PM   #4
gbhil
Planted Tank Obsessed
 
gbhil's Avatar
 
PTrader: (7/100%)
Join Date: Oct 2005
Location: Bunker Hill, WV
Posts: 346
Default

Actually Shalu's test show a T8 overdriven at 4x gives 380% light output

Quote:
Originally Posted by shalu
.....ok, I bought some 18" and 48" T8 bulbs today from Home Depot just to do this test. I have updated the spreadsheet above with 48" T8 resuts. Take a look. My observations with T8:

....snip.........
The total light output is an astonishing 3.8x at 4x OD, while power consumption is less than 2.5x!
....snip.........
gbhil is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 07:15 PM   #5
co2
Planted Tank Obsessed
 
co2's Avatar
 
PTrader: (8/100%)
Join Date: Sep 2004
Location: SF Bay Area
Posts: 459
Send a message via AIM to co2 Send a message via Yahoo to co2
Default

ODNO is such a waste of electricity. They take up a lot of space and generate a lot of heat. It is a fire risk as well:

http://www.plantedtank.net/forums/li...ight=ODNO+fire

Do yourself a favor and use compact flourescent or T5 lighting with a good reflector.
__________________
-Craig
co2 is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 08:00 PM   #6
gbhil
Planted Tank Obsessed
 
gbhil's Avatar
 
PTrader: (7/100%)
Join Date: Oct 2005
Location: Bunker Hill, WV
Posts: 346
Default

Quote:
ODNO is such a waste of electricity
A T8 lamp driven 4x uses ~56 watts of electricity. A 65 watt PC lamp uses 65 watts, and 2 are required to light 48" of tank length. An ODNO4x T8 32 watt lamp puts out more lumens than a 65 watt PC lamp.

Quote:
They take up a lot of space
8/12" diameter 47.5" length.
Please explain how your creative method of measurment saves space when using T5 lamps or PC lamps?

Quote:
generate a lot of heat
Compared to what? PC lamps are hotter.

Quote:
It is a fire risk as well:

http://www.plantedtank.net/forums/li...ight=ODNO+fire
There is just as much evidence and speculation in that thread that it was the Coralife fixture that started the fire. If you compare the numbers of reported fires from properly wired ODNO setups to the numbers reported for standard HO and VHO T12 setups I'll bet you'd be surprised.

In the same spirit, I have an 8x54 watt SLS Tek-Light fixture in my garage in which the ballast wiring caught fire. Reefgeek/SLS replaced the entire unit under warranty after seeing photos of the ballast wiring that burnt in half. So in your opinion are Tek-Lights and T5 setups in general an unsafe fire risk?
gbhil is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 09:07 PM   #7
MoonFish
Planted Member
 
PTrader: (5/100%)
Join Date: Feb 2006
Location: central iowa
Posts: 227
Default

peter, you will need some ventilation. My hood now is fully enclosed with no fans and it adds noticable heat when you open the hood. I have four bulbs all 2x and most plants grow ok. Glosso is standing kinda tall but it grows just fine. I don't know how efficient it is. My electric bill went up like $40 when I added this tank. I'm not sure if that is all normal or not.

I bought some pretty decent reflectors and I think that it is a good investment. You only pay for them once. I don't think a lot of people have t8's and good reflectors to make comparisons. Now people like t5's because they do come with good reflectors for the most part.
MoonFish is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 09:18 PM   #8
co2
Planted Tank Obsessed
 
co2's Avatar
 
PTrader: (8/100%)
Join Date: Sep 2004
Location: SF Bay Area
Posts: 459
Send a message via AIM to co2 Send a message via Yahoo to co2
Default

gbhil,

If you take a 55 watt PC from AH Supply with one of their reflectors, and a T8 driven 4x, which one will put more light in the tank? Every ODNO setup I have seen has a poor quality reflector. What is the best reflector you can use for T8? It doesn't seem like there is anything made that compares to the quality of AH Supply reflectors or the individual T5 reflectors that are out there.

As far as them taking up too much space... I was off track with that one

Do you have temperature measurements to back up your statement? They both generate a lot of heat, but when people talk about ODNO it seems like they always compliment on how much heat they generate. My statement was based on speculation but your's probably was too.

Do you honestly feel that an ODNO setup (using a ballast in a way it is NOT intended to be used) is safer than using a 55 watt PC ballast the way it IS intended to be used?

I think that the majority of people would agree that PC's are safer, and due to the availability of better reflectors, more efficient than ODNO.
__________________
-Craig
co2 is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 09:43 PM   #9
BlueRam
Wannabe Guru
 
BlueRam's Avatar
 
PTrader: (0/0%)
Join Date: Sep 2004
Location: Seattle, WA
Posts: 1,662
Default

CO2:

A big factor in ODNO is that the cost is substantially less than anything else out there.

Think of T8 ODNO as a form of HO T12 or VHO T12. Even the T5 HO is a factory OD T5 so it is a common method.
__________________
Greater Seattle Aquarium Society Member (GSAS.org)
General Auction April 18th 2009!!!
Community 60 gal T8 +CO2 +sump.
Clown Barbs 75 gal T8 +sump
Goodeidae project 20Long PC
BlueRam is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 10:28 PM   #10
darkfury18
Planted Member
 
PTrader: (22/100%)
Join Date: Apr 2006
Location: Tucson, AZ
Posts: 259
Default

Quote:
Originally Posted by gbhil
Actually Shalu's test show a T8 overdriven at 4x gives 380% light output
If you look at the table at the top, a T-8 at 4x outputs 320 (whatever unit that it's in) while a NO is at 150. So that is just over 200%... What you're reading is not the measurement but an estimation to show that ODNO is much better that NO because most NO are underdriven and has a poor efficiency. So if you were to drive 4 bulbs with that one ballast, you would waste a lot of power (thus using 2.5x the power) and not have great light output because the bulbs are undriven with the .88 ratio (giving the 3.8x light- a comparison between an underdriven bulb and a maxed out bulb).

Quote:
Every ODNO setup I have seen has a poor quality reflector.
http://www.plantedtank.net/forums/ph...ate-6-1-a.html
darkfury18 is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 11:07 PM   #11
gbhil
Planted Tank Obsessed
 
gbhil's Avatar
 
PTrader: (7/100%)
Join Date: Oct 2005
Location: Bunker Hill, WV
Posts: 346
Default

co2 -
I'll concede that AH supply 55 watt + reflector puts more light into a tank than ODNO T5 with standard available reflectors. What most people do not know, is the MIRO 95% polished specular aluminum reflectors AH uses are also made sized for linear T8 bulbs. MetalOptics from Austin TX is one place I know of to get them. Of course spending the cash on them defeats the purpose of running ODNO lighting.

Like you, I'm using the tried and true 'how hot it feels on my hand' way to test bulb temperatures. I can dig up my temp gun and have a look what it says, but I don't have any PC bulbs of comparable size here running.

Quote:
Do you honestly feel that an ODNO setup (using a ballast in a way it is NOT intended to be used) is safer than using a 55 watt PC ballast the way it IS intended to be used?
It's just as safe. You're not using the ballast in a way is wasn't designed. The ballast has a built in safety circuit and will cut out before it pushes out more voltage or amperage than it was safety tested to run. I worked in the industrial lighting field for 18 years, and have done things to ballasts and lamps that would make you cringe. Running it to it's full listed potential is not one of those things. 18 gauge wire is rated for 22 amps when used in a chassis, and 600V. The industry standard tombstone is rated for 600 volts and 660 watts. This leaves us with the lamp. I have no way of proving it, but it's common knowledge that fluorescent lamps are very underrated. Anyone in the lighting/luminary industry will confirm this. I feel extremely confident in the ability of a T12 or T8 lamp to withstand the 'abuse' running it at 4x puts it through. People with several years experience running ODNO will likely agree with me.

Quote:
I think that the majority of people would agree that PC's are safer, and due to the availability of better reflectors, more efficient than ODNO.
They may agree, but does that make them correct? ODNO isn't for everyone. But when done correctly isn't the dangerous monster many feel it is.
gbhil is offline   Reply With Quote Quick reply to this message
Old 06-04-2006, 11:39 PM   #12
gbhil
Planted Tank Obsessed
 
gbhil's Avatar
 
PTrader: (7/100%)
Join Date: Oct 2005
Location: Bunker Hill, WV
Posts: 346
Default

Quote:
Originally Posted by darkfury18
If you look at the table at the top, a T-8 at 4x outputs 320 (whatever unit that it's in) while a NO is at 150. So that is just over 200%... What you're reading is not the measurement but an estimation to show that ODNO is much better that NO because most NO are underdriven and has a poor efficiency. So if you were to drive 4 bulbs with that one ballast, you would waste a lot of power (thus using 2.5x the power) and not have great light output because the bulbs are undriven with the .88 ratio (giving the 3.8x light- a comparison between an underdriven bulb and a maxed out bulb).



http://www.plantedtank.net/forums/ph...ate-6-1-a.html
We're on the same page, but describing it differently.
A - 4 lamp fixture using 4 ballasts driving the lamps = 'maxxed out bulbs'
B - 4 lamp fixture using 1 ballast to drive the lamps = 'underdriven bulbs'
in this situation A outputs 3-3.5x more lumens than B, because one set is overdriven and one set is underdriven. But IMO they aren't 'underdriven' as that is their standard operating range, regardless of whats stamped on the lamp. Simply a question of opinion and semantics, but I do understand your point.

Running one lamp on a four lamp ballast and capping off the three other unused leads will drive the lamp much closer to it's nominal wattage rating, probably even slightly over.

BTW -very nice diy reflector!
gbhil is offline   Reply With Quote Quick reply to this message
Old 06-05-2006, 01:00 PM   #13
jgc
Planted Tank Enthusiast
 
PTrader: (0/0%)
Join Date: Jul 2005
Location: Austin, TX
Posts: 944
Default

Let's face it - combining water and electricity is inherently dangerious. I read a few pages (something between 100 and 150) on endcap fires before I tried odno. To be honest - I only recall the one case about that odno was even a possible culprid.

The sad thing is after reading all those pages, endcap fires are still considered by most a random mistery. My wag on the matter is that they are caused by quite a few events that agrivate each other. Corrosion and heat are the biggest. heat can cause thermal expansion that leaves gaps, gaps in high humidity environments corrode and causing arching, arching causes large increases in heat - repeat cycle. Eventually the heat will cause other parts to start to fail and probably increase the heat production.

While a 2x odno doess produce more heat - I can still grab the bulb while it is burning - and hold it for 10-15 seconds. Dare you to do that with my 250 watt hqi.

Anyway, I think 4 t8's with 2x odno from workhorse ballists will put out a nice amount of light. Give them decent reflectors and you have a high light enviroment. I had 2 2x and 2 no with poor reflectors and got increadable pearling.
__________________
58 gallon oceanic, 250w 10k pendent, pressurized co2, eheim pimp #179 - 2217 and diffuser
jgc is offline   Reply With Quote Quick reply to this message
Old 06-05-2006, 02:29 PM   #14
co2
Planted Tank Obsessed
 
co2's Avatar
 
PTrader: (8/100%)
Join Date: Sep 2004
Location: SF Bay Area
Posts: 459
Send a message via AIM to co2 Send a message via Yahoo to co2
Default

Quote:
Originally Posted by darkfury18

Quote:
Originally Posted by co2
Every ODNO setup I have seen has a poor quality reflector.


http://www.plantedtank.net/forums/ph...ate-6-1-a.html
First off, I want to say that you guys have made some good points here. I had considered ODNO when I first started but made the decision that it wasn't for me. It might make sense for some people.

However the reflector that is shown above... while being the best reflector I have seen used with ODNO still doesn't seem that great. The bulbs aren't centered, so the reflector is definitely not optomized for T8's and it's really wide, 12" is 50% wider than two rows of 55w PC's.
__________________
-Craig
co2 is offline   Reply With Quote Quick reply to this message
Old 06-05-2006, 11:28 PM   #15
Peter
Algae Grower
 
PTrader: (0/0%)
Join Date: Apr 2005
Location: Norway
Posts: 17
Default

Thanks everyone for your responses.

I was surprised by the $40 additional cost MoonFish said a new tank added to his monthly bill. With my 40 gallon, I purposely stuck with 4 bulbs NO to keep the costs down. That's not really possible with a 75 gallon due to the width. Plus, reading Shalu's sticky thread, it seems that NO is, in any case, also inefficient as it under drives the bulbs. Has anyone ever looked at what is the most efficient ODNO load for a 32 watt 48" bulb? eg, 2X.

Looking at the first response to my question, the formula for computing actual wattage: (4x 32 watts x.88) x .75 heat loss) x 3 ballasts = 253 watts = 3.4 wpg on a 75 gallon tank. If I want to get 200 watts (2.7 wpg) or thereabouts, what ODNO scheme would you recommend and would there be substantially less cost per month? I'm just looking for reasonable high light at a reasonable monthly price. I'm now running 2.7 wpg on my 40 gallon and it works great for me.
Peter is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 04:37 PM.


Powered by vBulletin®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright Planted Tank LLC 2012