I have seen some of these lights (for illuminating driveways etc) and am wondering "why not?" I can buy one of these units for 9 (~$15), whereas to equip my tank with flourescents, ballasts etc would cost me well over 100 ($150). Is there an "absolutely not" type reason? (apologies if this is posted twwice, it did not turn up my server, although it must have got somewhere because I got a reply!) <<<<<<<<<<<<<<<<<<Spug (Sparrow) London, UK.>>>>>>>>>>>>>>>>>>>>