TheCanuck;3860414; said:glass will give off a green tint if your tank is older. I see you have a strip light that has two white bulbs. I had this same problem , you need to put a purple or blue attinic with the white light. That will fix your problem
Take a look at your lighting, When I ran my fish room, it was vital that my tanks all had that "Crystal Clear" appearance. Everything mentioned will have an effect but the biggest is lighting.
You do not have to replace the light fixture just the bulbs, most pet stores will carry quite a variety of bulb "temperatures" but it is important to keep you fishes natural habitat in mind, i.e. river fish expect warmer temps and reef fish expect cooler temps. (temps = light wavelength)
I personally prefer a nice blueish or cool light temperature myself and thus am partial to saltwater.
Sorry if this seems rambling but I hope it helps.
and now you have tons of options, all micron sizes