How much gravel?

[koimes]

Hi sorry if this is a noob question, I have a 25 gallon tank, with this internal power filter that hangs on the side of the tank
http://www.resun-china.com/en/ProductInfo.aspx?ProID=434&ProClass=119
I am thinking of getting live plants, and I've been reading various books on fishkeeping saying that a minimum of 5 cm of gravel is required, although this is always stated when dealing with an undergravel filter (which I don't have)

So my question is, how much gravel (in inches or cm) do I need for my tank if I want live plants in my tank? Thanks

 

[rusland005]

I use sand instead of gravel, but i would say use enough gravel to bed the plants to the the bottom, i'd go for less rather than more. 3cm?