I have a 75 gallon tank 48"L 18"W 21"H and i'm having a hard time finding a background. I went to a local petshop and I found one that looked like it might fit but the 'helper' there begged to differ.
What's the height I need for the background? I was thinking 18"H since the tank's plastic trim looks like it consumes about 3 inches or so of the 21"H.
Thanks.



