lighting for my 125 gallon tank - The Planted Tank Forum
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post #1 of 12 (permalink) Old 07-07-2004, 04:33 AM Thread Starter
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lighting for my 125 gallon tank

I am in the process of setting up a 125 gallon (72" x 18") tank to be heavily planted. I intend to eventually add my discus, after I have the new tank stabilized. I'm currently trying to sort out my exact lighting scheme, and I'd like some input.

Target water parameters:
pH 6.5, GH 3, KH 3, temp 82F, nitrate <20 ppm, DIY yeast CO2

I was originally planning to use 4x96 watts of compact fluorescents, but I've come across a really good deal on 4x55 kits utilizing the AHSupply reflector, Catalina Aquarium bulbs, and Fulham workhorse ballasts. Not only are these kits a good deal, but I'd like to be able to eventually use the GE 9235K bulbs that everyone seems to love, so I decided to avoid the 96 watt kits. I'm looking at using either 6 or 9 55 watt bulbs. I have the choice of either 6500K or 10000K Catalina bulbs.

All this said, I have two basic lighting issues I'd like help sorting out:

How many bulbs should I use, 6 (330 watts) or 9(495 watts), or perhaps somewhere in between (2 complete rows plus a partial row)?

Obviously, my priority is to get great light to the plants, but I also don't want that pinkish "gro-light" cast on everything. What combination of the 6500K and 10000K bulbs should I use to get a good useful and aesthetic balance; 50/50, 66/33, 33/66, etc? Also, if I force my budget and go ahead and get some of the GE 9235K bulbs, which of the Catalina bulbs should I mix these with and at what ratio?

Ive also got a couple of other things Im curious about, for anyone that may have dealt with similar circumstances:

I listed 82F as my target temp, but this is because I'd prefer not to seriously limit my plant choices. Otherwise, I'd rather run around 84 - 86 for the discus. What would you say is the max temperature I can run the tank without significantly limiting my plant selection?

The canopy I built provides approximately 6 of air space above the tanks glass tops, and is completely open at the back. Should I mount the 2 tall AHSupply reflectors so that they are directly on the glass, or at the top of the air space? Also, will I likely build up too much heat in the canopy such that Ill need cooling fans, keeping in mind that Ill be utilizing 330 495 watts of compact fluorescents?

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post #2 of 12 (permalink) Old 07-07-2004, 11:06 AM
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I keep my discus tanks' temp between 80-84. I don't think they really need more than that.

You may want to get a small electric fan just to blow the hot air out. It may increase your bulbs' life too.

I've never set up a planted discus tank but I would think that 330 will be more ideal for discus than the higher wattage.

The combination ratio is really up to you. I usually do 50/50 between 6700 and 8800 or 10000 or 9325. I'm getting tired of the 9325 pinkish color. I know plants love it but I don't. I'm not gonna use them no more after they reach 1 year old.

If I have that tank, I would just Overdrive 4x four or six 36" or 48" NO flourescent. It's gonna be cheaper in the long run. If you run 9 55 watts bulbs, it will cost you over $200 for annual bulbs change. Just my 2-cent

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post #3 of 12 (permalink) Old 07-07-2004, 12:07 PM Thread Starter
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Yeah, I thought about overdriving, but it seems like 36" bulbs are really hard to come by (plus far less efficient than 48") and 48" bulbs would have to be staggered, so I am concerned about an uneven spread of light. Is anyone using 48" bulbs to light a 72" aquarium? If so, how's it working out? Also, the 4 bulb electronic ballasts I've seen are rated for 4 T8 32 watt bulbs, not T12 40 watt. Can you in fact use one of these to 4x overdrive 40 watt bulbs?

Anyone reading this, please continue to respond to the original post as well.

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post #4 of 12 (permalink) Old 07-09-2004, 03:42 AM Thread Starter
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Ok, I'm still looking for advice/opinions regarding my original post. I've also got a couple of pieces of information to add.

I've ordered my light kits to be here in a few days. I ended up ordering 5 of the AHSupply 2x55 watt kits. I intend to install 3 of them right away, for 330 watts (2 rows of three bulbs) and the other 2 kits will be added if need be or otherwise used on other tank(s).

I went to Atlanta Light Bulbs today and bought 5 of the GE 9325K bulbs for $17.95 each and 5 6500K bulbs made by Eiko for $10.95 each. The Eikos are rated at 4800 lumens and CRI was around 85. Does anyone know anything about these particular bulbs? If so, are they pretty comparable to the Catalina Aquarium 6500K bulbs?
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post #5 of 12 (permalink) Old 07-09-2004, 12:46 PM
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You ordered 550 watts of light? How many tanks are we talking about here? I think you will find that with 330 watts of light that your 125 gallon tank is going to be a real monster to keep on top of. You are going to need CO2 injection right from the start. Also you are going to need cooling fans in the canopy and will want to mount the lights as high in the canopy as you can.

The WPG rule breaks down on larger tanks such as your 125 gallon tank. Hope you are in for a fast ride.
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post #6 of 12 (permalink) Old 07-09-2004, 03:43 PM Thread Starter
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I ordered 5 kits of 2 each because I found an incredible deal on them. I've planning to put one of the kits on a 29 gallon tank and the other split between two 20 gallon tanks.

Regarding the 330 watts over the 125, I'm a bit confused. My previous planted tank was a 55g (4 sq. ft.) with 160watts of NO fluorescents. It worked wonderfully. The 125 is 9 sq. ft., so I would think eqivalent lighting would be 360 watts, if the tank were no taller, but of course, it is.

Can you give me futher detail on the problem? Also, what would you recommend? Should I just run 2 of the kits, for 220 watts total?

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post #7 of 12 (permalink) Old 07-09-2004, 05:46 PM
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I am using the 4x96W AH supply kit on my 150 gal tank. The 150 has the same foot print as your 125, but is about 5" taller. I built a light box (not a complete canopy) that sits on top of the glass covers. I've raised the box 1/2 inch off the glass via pieces of wood at each corner so that I have an air gap between the box and covers. I have fans installed at each end of the box which suck air out of the box so that air is drawn through the air gap under the box and across the bulbs.

With a 1/2 gap the glass gets somewhat hot. It doesn't appear to be affecting the temperature in the aquarium, though. I'm using a reef tank that has dual overflows so I get good surface movement which may help keep the surface water cool.

I don't think you need to mount your lights all the way at the top of your canopy, but I wouldn't put them all the way down either. If you've got glass covers on your tank then you could probably get away with putting the reflectors as close as an inch or two if you wanted. I would definitely install some fans to get air movement. If the back is open you may be able to just install some fans that suck air out of the canopy. The idea is to get air movement across the bulbs so you may have to look at your layout and determine how best to do that.

The amount of light I have is probably a little under what it takes to grow high light plants well, especially considering the height of my tank. My red lotus does nothing but send up surface runners which would indicate to me it doesn't get enough light to keep its leaves low. You may be a little low on light as well if you want high light plants. Your tank is shorter, though, so it may not be as bad.

I personally went with all 6500K bulbs, mainly because I like how they light the tank. I don't know that you'll notice a big difference in plant growth between the different K bulbs. There's been tons of discussions on here and other forums so you can read all you want. To me, it's more of how you want the aquarium to look.

Your setup shows DIY yeast CO2. I don't think that will work well in a 125 gal tank. You'll probably want to invest in a pressurized system from the start. I think that will work much better.

Good luck on getting your tank up and running. Take it slow and make sure you get everything right the first time. It took me a month to get my 150 up and running, but I've had zero problems since it's been up.

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post #8 of 12 (permalink) Old 07-09-2004, 08:13 PM Thread Starter
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Why do you think DIY yeast won't work well? If figured since (1) 2 litre bottle worked well for a 55g, (2) or (3) would work well for a tank that is just a little over twice the capacity?
What would it probably cost for me to get started with what you suggest for CO2?

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post #9 of 12 (permalink) Old 07-10-2004, 02:06 AM
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I cover the breakdown of the watts per gallon rule in my FAQ. And the height of a tank barely makes a difference at all if you have good reflectors. In fact the quality of the reflectors make a much bigger difference than the height of the tank. Someone on one of the forums I frequent did a pretty good analysis of the height thing and the difference between a 18" tall tank and a 24" tall tank was in the range of 1-2%.

The thing with the AH Supply reflectors is that they really don't give a lot of spread. They pretty much punch the light straight down. So you could have plenty of light over the tank and the problem would be in the spread of the light.

As for DIY CO2 on a 125 gallon it would be more trouble than it would be worth. If you are willing to shop around and build your own reactor you could have a manual CO2 system for around $120 or so.
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post #10 of 12 (permalink) Old 07-10-2004, 04:49 PM
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Might be a little late but I thought I would pipe my 0.02 cents. I built a canopy for my 125 that was 8 inches high that housed 6 30w NO flos and two 65 w PC. I had a slit in the top that went the length of the hood. I never had a heat issue with this canopy, no fans, no nothing. Just the open back and the slit. the slit was posistioned directly over the back of the relectors for the PCs so very little light escaped. I ran 4 phillips 65K, 2 GE day lights and two 55 w 9325s and I don't think that the color was bad.

I just upgraded to three MH and I love it, don't think i'll ever go back on this tank. Unfortunately I'm still running DIY CO2 and I can't get my CO2 high enough with the MH. I have everything, but a tank for pressurized. So soon as that comes in I'm hoping I can balance the tank better.

Good Luck!

Currently tankless for the first time in 24 years... Getting the itch again
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post #11 of 12 (permalink) Old 07-11-2004, 09:56 AM
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Rex, did you not see that he said he'd use the extra lamps on other tanks?

Why do you say the AH reflectors aren't good when those are the reflectors you recommend in your FAQ? Are they good or are they not? Make up your fricken mind!

IN ADDITION - In your FAQ, you say that a 75 gallon tank needs 220 watts of light - how, then, would a 125 not need 330 watts, since it is basically the same dimensions but 2 feet (50%) longer. 220 + 110 (50%) = 330, the way I do math.
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post #12 of 12 (permalink) Old 07-11-2004, 01:21 PM
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The AH Supply reflectors are awesome reflectors. But they are not diffusers. They really do PUNCH THE LIGHT STRAIGHT DOWN INTO THE TANK just like I said. If you have a tank like a 30 breeder that is 18" wide but only 16" tall you will run into coverage problems with a single AH Supply reflector. You won't get an even spread of light front to back of the tank with the strip mounted in the middle. And it gets even worse as you move up in the water column. By the time you reach the surface you would only have a small area of water actually getting light.

And I did not SAY that a 75 gallon tank needs 220 watts of light. I used the 55 and 75 gallon tanks as examples with 220 watts. Each is a high light tank. I can take the example one more step by using the standard 120 gallon tank which is basically two 55 gallon tanks placed front to back with a bit of added height. 220 watts of light is a lot of light over this tank also. But due to the added width you might not get total coverage across the tank with the AH Supply reflectors.
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