[TedP]

I have a standard 2.5g that I have about a half inch sloped to an inch and a half of substrate. The tank is 8" deep I believe. Would a 1x18w PC fixture from Catalina be enough to maintain a carpet of HC and maybe a bush of Blyxa? I'm going to have some sort of CO2 going for sure.

I think the fixture feet are about 2" tall so the light would be 8.5 to 9.5 inches above the substrate.

They also have a 2x18w fixture but I think that's too much based on the Hoppy sticky.

 

[2in10]

I think it would be plenty

 

[xmas_one]

The smaller tanks get, the more light they need, seems counter-intuitive, but it's true. I'd go with the 2x18 if you can run it one bulb at a time in case the two are too much.

 

[TedP]

My mistake. They are 13watt. But I don't think that would make much of a difference.

 

[xmas_one]

http://www.aquaticplantcentral.com/forumapc/aquascaping/55115-2-5g-aquascape.html

 

[PinoyBoy]

One 13w bulb directly on top of 2.5g, wasn't enough to grow me an HC carpet. Maybe it was due to the lack of co2, but it didn't carpet for me. The light is about 8 inches from the substrate, I have 1.5inch all around.

I would definitely get the 2x13w light, especially if you're able to turn one off just incase.

 

[TedP]

Thanks for the replies and thanks for the link Xmas. Interesting. I believe the Catalina Lighthouse fixture I was looking at has one cord and one switch. I could pull one bulb if it ends up being too much. I may be able to mod in a second switch too.

They also have a 9" long 3x13w fixture. . Still one cord and switch though.