4x36watts vs 2x55watts?

[awrieger]

Hi. I've just bought a compact fluoro fixture for my 3' (35gal) tank and it has 4 x 36 watt tubes. There's not much choice so it's basically all I could find here for this sized tank.

But they told me (after I bought it!) that the manufacturer can make custom configurations within the same fixture, ie 2 x 55watt tubes.

The 4x36w gives 4.11watts/gallon, while the 2x55w woud give an exact 3watts/gal.

Would I have been better off with 2x55s? Is the tube wattage more important than the total wattage?


(PS. The 55w tubes are available in 'plant pink' spectrum, while the 36w tubes don't have that option and only come in 6500K or 10000K.)

[Spar]

are there independent switches for each of the 36w sockets? mine do, which is why I was wondering. You could just flip one off to give you pretty much exactly what a 2x55 would.

Or... if you have a lid on the tank to keep condensation from sneaking up into the sockets, you could just keep one bulb out (empty socket)? or, ask someone to ship you their burned out bulb just as a space taker.

Really up to you on the big decision, which is returning the 4 socket and buying a 2 socket, as to the how bulky you want the light setup to look. I can only imagine that the 2 socket would look better.

[awrieger]

Thanks for replying Spar! Only each row of two tubes has its own plug so you can switch the front or back row on separately (or put them on different timers).

What they were talking about was putting different ballast and tubes into exactly the same fixture. So intead of two rows of 2 x 36w tubes, it would have a single longer 55w in each row (plugging in at opposite ends and overlapping a bit in the middle).

The 4x36w is like this ==

and the 2x55s would be like this _-- (without that little break in the top tube of course).

I guess what I'm really wondering is if the tube wattage itself makes any difference. Is a higher watt tube better for plants? So what you're saying it shouldn't make any difference as long as the total is okay?

Thanks for the suggestion. I'll likely just try running the full set at 4w/g though and see if I can get some good growth going. Maybe switch the front row on later and off earlier than the back row to simulate daylight (bright daylight!).

[Spar]

i have 4 65w's on my tank, giving me 260w total over 50g's of water. So almost at 5.2wpg. The lights stay on for 11 hours per day. As far as I can tell, my plants are doing great and have un-controllable growth

I do however inject 30ppm co2, and heavily fertilize the plants. Almost 3-4x what is reccommended in Traces.

So, the higher wpg isn't necessarily bad. You just may have to play with your other settings a little more. That said, I would recommend just saving your money and sticking with the higher wpg rather than paying to have a custom fitting placed.

[malkore]

Either fixture will grow plants just fine. With the 4x36, you'll need stead CO2 injection (I'd honestly go pressurized) and consistent fertilizer dosing too.
And probably only need a 10 hour photo period.