Extra filter to "polish" water

[Anaxus]

On my 37 gallon high eclipse tank the water has a slight brownish look to it when looking from the side. When looking from the front it is clear. So I was thinking that maby the eclipse system doesn't turn over the water enough for it to completely "polish" the water. I was thinking of adding another filter just for water "polishing". I have three choices:
A) Powerhead with a spong prefilter
If this choice what brand?
B) Internal filter
If this choice what brand?
C) Ehiem canister filter that I already have which is not being used. I think it is rated for up to 30 gallons maby higher. If I go with this what filter media? I think it already has filter floss which takes up half the canister. Should I get another filter floss or maby some bio media?

[cdawson]

Go with the canister or the powerhead, you've already got one filter in view doing the main job. Try and make the other a little less noticeable, that's what I'd do IMO.

[OrionGirl]

If you have any wood in the tank, this is probably the source of the coloration. While not detrimental to the tank or fish, the tannins will color the water, and can be unattractive to some. A bit of carbon, run 2-3 days once a month, will likely be enough to remove the color. The Eclipse filters usually have some carbon in the cartridges, but this will quickly used up in the normal course of running. Rather than replace the entire cartridge, wee if you can get some carbon chips and a small nylon bag that you can tuck somewhere within the compartment.

[Anaxus]

I never thought of tannins. It is probably that since I have 1 piece of curio wood in the tank. I will see about getting a mesh bag with some carbon if not I guess it isnt a big deal.

[nolemite]

As stated, carbon removes colour from water. Other people would go with a diatomaceous earth filter.