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Discussion Starter · #1 ·
hi all, i am new to this forum and to planted tanks. I'm starting a 75 gallon planted tank with anubias, java fern, and java moss to start. I plan to us diy co2 but i'm unsure about what lighting to us. I found a 48" 216w t5ho fixture and my question is whether or not this fixture is overkill or the fixture i need. If i could get away with a cheaper 108w fixture that would always be better. Any thoughts?

thanks:D
 

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The problem with lighting that tank is the 18 inch front to back depth. That makes it hard for a single light in the middle of the top of the tank to adequately light the whole tank. You could use the 4 bulb fixture if you hang it about 30 inches from the substrate, but that will be high light, and you will need pressurized CO2 running almost at the bubble rate that will kill the fish to be able to avoid a lot of algae problems. A much easier to manage light level would be low medium light, but that would require hanging the light about 36 inches above the substrate. If you just use two of the bulbs, you can hang it about 30 inches above the substrate to get low medium light, or lay it on top of the tank to get high light.

It will be hard to keep up with the CO2 demand on that size tank, using DIY CO2. You could try it with low medium light, but it won't work at all for high light.
 

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Get the 4x fixture and run only 2 bulbs. Thats still a lot of light for your plants and DIY Co2; you can filter some of that light with a bug screen commonly used in windows, if you don't want to hang it so high above the tank.

Go with the expensive fixture now. Then you have the option to go pressurized if you would like, or not, at least you have the option without having to buy another light in the future.

Make sure you are diffusing 100% of your co2, its gonna be a challenge getting acceptable levels in a 75g via DIY.
 

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Discussion Starter · #5 ·
thanks everyone for the help.:D i think i'm going to go with the the 4 light fixture and us only 2 lights. also i will seriously consider pressurized co2.

thanks again
 

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On my 75 gallon I have 2, 2 bulb T5NO fixtures. This allows me to run anywhere from 1 - 4 bulbs and have the front to back spread I need easily when running only 2 bulbs, one in each fixture. So far for me it seems 3 bulbs for 8 hrs a day is just a bit too much to keep algea down with no CO2 injection, but weekly fertilizer use.

I am cutting the light back a bit, but I also have the ability to kick it up a notch if I decide to add CO2 in the future.

I have no problem growing java fern, anubias, crypts, chainswords and some easy stems like wisteria at the 2 bulb T5NO level.

Just another option to think about. Probably just what you wanted.:icon_wink
 

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It will be hard to keep up with the CO2 demand on that size tank, using DIY CO2. You could try it with low medium light, but it won't work at all for high light.
VERY VERY hard...I don't recommend DIY on anything larger than 40gal. I used 2 1gallon containers on my 55gal and barely hit 20ppms. It will require at least 4 containers, and it wont be fun.
 
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