making lights a bit duller

[niknaksky]

Hi all,

Any idea how I can tone down the light a bit on my river reef ?

At the moment I am using one light in the hood but its still a bit to bright for my betta channoides.

I bought it to setup as a nano but then came across the betta channoides and could not resist

What I was thinking was to wrap bits of tin foil round the tube ever so many inches would this cause the light to over heat ?