Here is the bulb:
Printable View
Here is the bulb:
Pic after 1st week of use.
bulb is on a timer: 16hours on, 8 hours off
Yours looks similar to mine. I used a piece of tile.
On the piece of plastic canvas, I have tried to put a piece on mine and the water doesn't flow across the screen. Just kinda under it. I would suspect that you would get the same results. I have twice the flow going over mine as I have upgraded my pump so I now flow 400GPH over a 7" wide screen.
Maybe SM can chime in here and tell how it should be. What I mean is, to let us know how the water should flow on this style of scrubber.
Will the water go over the screen when algae starts to grow?
The difference that the canvas makes is when algae is thick, and when you clean it. When it's thick, it will let go by itself if it can't grab onto the screen. So without a screen, it's performance is reduced as pieces let go into the tank. And when you clean without a screen, you have nothing left over, so you have to wait a few days before filtering gets going again.
It's ok if the water goes under, because after the growing get full, it will grow through the screen.
The cutting board I am using actually has a rough, corrugated surface (not to mention all the cut lines, becuase I ended up using the old one). I think algae will stick, but I will keep a close watch on that.
updates 2/28
I remember that cutting boards are made out of Teflon. So when green algae gets thick enough, the water flow will pull them off of the surface. You'll have to clean more often to offset this.
Going to be out of town this week, but I am going to add a platic canvas and increase the flow.
If it is teflon, that's PTFE (as in the plumber's tape and the type of plastic), apparently, it's considered to be the best low friction, no-slip surface available (used to coat windscreen wiper blades also so they don't stick to the glass), so probably not inherently good for algae to attach to as SantaMonica suggests =).
The other good thing about using a mesh on top is that the bits of algae get stuck in between the holes so when you clean it they can regrow nice and quickly, especially useful when doing one-sided lighting like this (exactly what I'll be doing).