46 gal low tech light help

[starccc]

Will set up a 46 gal low tech tank. Currently, there are 2x 55 CF in it. The tank is 20" height. If it is too little to just use one light? I think 2x55w will be too high for low light.

[Hilde]

Originally Posted by starccc

The tank is 20" height. If it is too little to just use one light? I think 2x55w will be too high for low light.

Dude I don't think you can grow anything but moss and ferns with that light. For I don't think the light from CFL bulbs will get down to the bottom. A T8 10000K would work better if you just want green plants. That is what Trallen used over his tank. Probably need more if the tank is more than 12 wide. For read that If the tank width is more than 12 inches use two fixtures, or a fixture with two bulbs separated by 6 inches or so, to get uniform light.

Saw that you have a thread that you were leaving the hobby in 2010. Guess you still have the bug. He!! He!!

[starccc]

Do you mean 1 CF light? I know 2x55W for 20" height 46 gal tank is enough to grow a lot of plants from my experience.

This was what I got from this setup.
46 gal

2x55W CF, CO2, water change every two week.

High tech tank need too much work. The plants grow too fast.

I moved to another states so had to leave hobby when leaving... Now I have some time to start it again and I still have my old 46 gal tank. This time, I want to setup a low-tech tank that need no to very little work. I know t5 or T8 might be better for this setup. But I want to use my existed lighting. It is 2x55/65w 6700k AHsupply light. 1CF or 2CF?

Originally Posted by Hilde

Dude I don't think you can grow anything but moss and ferns with that light. For I don't think the light from CFL bulbs will get down to the bottom. A T8 10000K would work better if you just want green plants. That is what Trallen used over his tank. Probably need more if the tank is more than 12 wide. For read that If the tank width is more than 12 inches use two fixtures, or a fixture with two bulbs separated by 6 inches or so, to get uniform light.

Saw that you have a thread that you were leaving the hobby in 2010. Guess you still have the bug. He!! He!!

[kevmo911]

Well, since the AHSupply reflectors are excellent, if you have them mounted directly on (or a few inches up) your tank, two might be too much light for non-CO2. Somebody with more experience can chime in here, but looking at the PAR sticky in the lighting forum (the first chart - the second only has "average" PC reflectors), 20 inches with one bulb puts you in medium light range, which will be the uppermost limit without CO2. Assuming you have a few inches of substrate and a few inches of clearance above the tank, that sounds perfect.

The one issue I can think of would be light distribution. One bulb will leave the front and back a bit dim. Is there any way to use two lights but raise them up a foot?

[Aether.ed]

It may sound crazy but my low light tank is thriving, its just java fern, anubias and moss but its all growing well in a puny 0.2 wpg of light! its just a 24w flourescent over a 120gal! Even the water hyacinth on the surface is multiplying like mad and these guys are meant to be mega high light plants! I use a cfl on my small tank and think the output is quite high for such a small light!

[starccc]

Thank you.. This is very helpful. For the light distribution, I will put the light in front of tank. The foreground plants are shorter so it can receive more light. I plan to make thick substrate and the distance to top should be smaller too.

Originally Posted by kevmo911

Well, since the AHSupply reflectors are excellent, if you have them mounted directly on (or a few inches up) your tank, two might be too much light for non-CO2. Somebody with more experience can chime in here, but looking at the PAR sticky in the lighting forum (the first chart - the second only has "average" PC reflectors), 20 inches with one bulb puts you in medium light range, which will be the uppermost limit without CO2. Assuming you have a few inches of substrate and a few inches of clearance above the tank, that sounds perfect.

The one issue I can think of would be light distribution. One bulb will leave the front and back a bit dim. Is there any way to use two lights but raise them up a foot?

[Hilde]

Oops!! Oh, so you aren't talking about the twisted bulbs that screw in. You have the bulbs from AH Supply? I had 1 CF 65 watt over my 29g tank. I wasn't happy with the color output thus had added a T8 18 watt life-glo over it. Just had a few inches from tank using the legs. It was 21 over tank that is 30in. My tank is a low tech (Excel for Co2) low maintenance tank.

Hoppy seems the most knowledgeable about par etc.

[kevmo911]

Originally Posted by Hilde

Wow!! I had read that the CFL bulbs (twisted bulbs) had a lot of restrike thus thought they were best for a small tank. Hoppy is the most knowledgeable about par etc.

One had a lot in a box but had some problems with heat. Others I have seen were 20L that are not as high as the 46 gallon tank.

Well, correct me if I'm wrong, but I believe starccc misspoke. We're not talking about CFLs here, we're talking about PC bulbs. AHSupply sells both T5HO and PC bulbs with excellent reflectors. I assumed this was what was reffered to.

But, on a side note, CFL's will be just fine for any length tank, given decent reflectors for that type (and enough bulb/reflector fixtures to cover the length of the tank). They're bulky, and have a narrow area of effect. Check the second sticky in the lighting forum, post #21 or thereabout, for more info.