If you haven't noticed, I really hate seeing technical "props" (filter intakes, returns, pumps, heaters, etc.) in my tanks. I mean, sometimes it's just unavoidable- you can't disguise or hide them easily.
One of my real favorite pieces of equipment is the VorTech pump from EcoTech Marine. It's a great water movement "weapon"-IMHO possibly the best internal pump available. Coming from the reef side of the fence, getting great water flow with minimal hassle and aesthetic disruption goes with the territory! This pump is perfect for the job. However, like many internal pumps, it suffers from one drawback: Part of it has to be in the tank...which means you can typically see it..
Well, you don't HAVE to see it. It consists of a "wet" side, which is essentially the propeller assembly, and a "dry" side, which is the motor. The "dry" side is placed outside the aquarium, with the propeller side inside the tank (duh). The two are coupled via strong magnets that hold them in place through the glass or acrylic. This arrangement effectively keeps the heat-transferring motor out of the tank entirely, which is not only efficient, but it makes accessing the pump a snap! This is a super efficient way to go, but you're still sort of limited in terms of mounting options. You'll typically see part of it on one side of your tank:
My fave trick for hiding this pump? Go through the bottom of your tank!
Yup- you heard me. Because when you go from the bottom, you can easily hide the wet side in rock work, wood work, or, I suppose, a dense thicket of plants. And, you can create all-over water movement in a vertical "gyre"-type flow arrangement, ranging from gentle to rip-roaring!
Of course, it requires a little elbow grease and preplanning.
You have to use a hole saw to drill a hole in the bottom of your aquarium stand (around 3-4 inches in diameter, depending upon which pump you're using) in order to accommodate the "dry" side and its need to couple magnetically through the glass to the "wet" side.. The obvious caveats here are that you can't compromise the structural integrity of your stand, so you can only do this if there is obvious support provided by your stand! And, if you're adverse to drilling the hole in your stand, it's not for you!
The above pic is a shot of the "dry side", shot from underneath the aquarium stand. You also need to notch out about 1.25" long by about 1/2" wide or so with a jigsaw to accommodate the power cable that comes from the dry side, so that it seats cleanly in the hole you drilled. It goes without saying that you need to determine exactly where on the bottom of the tank you want to position the pump before you drill the hole!
On the bottom of the tank, you mount the "wet" side over the dry side. Since the pump, even at low settings (and it has amazingly precise flow settings and programs, BTW) can pull in sand, debris- even unsuspecting fishes and snails- you need to create a sort of protective "shell" around it. This is easily accomplished by using a section of large diameter ABS or PVC drain coupling, with a slightly larger diameter than the pump. Use a bead of aquarium sealer to secure the pipe section to the bottom glass of the aquarium.
The end result is a perfectly positioned, well protected pump, ready to rock in your tank. Now, you will have to carefully hide the pipe section with some well-placed rock work, which is not at all difficult for the typical aquarist.
Leave a section of the rock work open at the top, in order to allow the water to flow upwards and allow easy access to the "wet" section for cleaning. Obviously, you'll have to adjust the settings on the flow, because this pump can easily blow water right out of your tank at high flow rates!
The end result of this little process is the creation of a strong vertical gyre that can (invisibly!) add incredibly efficient, precisely controllable "intelligent" water movement to your tank!
Have fun with this idea..
And stay wet!