How big can I go while keeping the same light?

[OCDP]

Updates..

Still waiting on the word for the Cube, and when it can be built, etc..

Over the weekend I added an AC500 to my 20g. This will more than likely be used as a fuge on the Cube tank. I love this thing, it adds a nice extra amount of flow to the back wall of the tank, so there are no dead spots in the back of the tank now. Also, I can run carbon and sponge now and already the tank water looks much more clear. Ahhhh.... carbon!

I also decided to go ahead and purchase a 24" Aqualight Pro. I should have this within the next couple weeks... I am really looking forward to using one of these fixtures. It is just much more sleek and nicer on the eyes. It will be great for my cube (24x24x18) Because now I have the 150w HQI + the 2 actinics. More light!

Would I be able to make the cube 24x24x20 now if I am using the aqualight pro? Or is the extra actinic not going to do too much for the tank?

Anyways... there's some progress, things are looking up. The two (well, three things really) that I need to get out of the way are the stand (which won't be built until April) The Cube... and I really want an RO/DI unit for this tank. I am just not sure if I will be able to add it as soon as I'd like.

That's all for now.