FX5 is definately an awesome filter, and very quiet, frankly, my air pump for the air stones is more noisy. For sand, if you have a pool supply store near you go with the pool filter sand, it is much easier to clean than play sand. Make sure you also buy filter media for the FX5, it only comes with the coarse sponges, you still have to fill the baskets with your choice of media. Check VeipaCray's media thread for suggestions. I used them with great success.
http://www.redearslider.com/forum/viewtopic.php?f=9&t=30145#p288938 The only thing he left out is how much media you need. (I'll get to that in a minute) If you are going with sand, do the optional config first, filter floss and carbon to clear the water , because you won't clean the sand well enough, few do.
About the quantity of media you will need. The media baskets in the FX5 are huge, get a cheap large bag of filter floss for your water polishing cycle, you won't need all of it, but it is cheap. You will need a lot of bio media, preferably the ceramic rings, get the cheapest ones, I used 5 500ml boxes, or 2.5 liters of bio-media. You will also need activated carbon, I used the pre-bagged ones from fluval 3/box, and used 2 of the bags along with one bag of purigen, you can go cheaper by buying carbon in bulk and bagging it yourself in unused nylons or the premade bags from the pet store. Also order a box of the blue floss pads from fluval for the FX5, there are 3 per box, and you will only need one of them for VeipaCray's setup, so you will have spares.
Tesla for about two months now. I love him dearly! However, now that I am back at work, I finally have some cash laying around to upgrade his filter and build him an ATBA to maximize his water room. 
