[Matt Nace]

Wood can give off tanins that color your water.

Your water changes are good, Try a 50% water change next time. You may still have a lot of nitrates built up from when the "gunk" was in the tank.

Make sure you clean your filter, but not the bio wheel part. Leave that alone.

After the 50% water change, you may need to add carbon(cant believe I am saying this) to get the yellow out. Hmm.yellow. Is the water clear..or is it a cloudy yellow? You can usually tell from the side. Mine are crystal clear from the side.

Make sure your flourencent bulb is not too old it can make your water look yellow, or even a blueish.Try buying a GE Daylight bulb for a nice white light.They are at home depot, and I seen them at wal-mart as well(in USA). I wonder if this is the problem, the bulb.

Is your glass free of algae?

If you buy a bigger grain sand, it might work ok with a siphon...but I can't tell you for a fact.I would think like a playsand size would get sucked up.

They have some real neat caves and plastic wood looking "gardens" at the fish stores.I have a rock that is a cave for a reptile, but I have it for fish. I liked it cause it looked like a rock...not plastic.

How about the front of the glass