The only problem I have with mounting it under the tank is if the tank leaks you have no assurance that the power strip will not get wet. I mount mine to the wall for this reason. If you can protect it under there then by all means do it.
I have a shallow pullout tray mounted high with keyboard slides...great for small supplies...also mounted the power strips on the inside wall....the best thing I did (and think every stand should have) was mount a low voltage puck light so I can see everything in the stand