><> Under Tank Filtration System

If you have a large tank 50 gallons and up, the best filtration system is an under tank filter using a sump. We built our own sump and filter system. Below I discuss how it is done.

><> Our First Sketch

We decided that we wanted to include a separate refugium in our filter system. The above sketch allowed us to get a rough idea of what we wanted. As you can see, the water flows in over the bioballs, up over and back over the glass panels, and through the second area with the algae and live sand. At this point it is pumped back to the tank. Your water is fine at this point. Optionally: We funneled a little of the water off to our refugium. The water level in the refugium is maintained by a pipe that runs back to the center tank.

After further research we settled on the next sketch. The main difference is the elimination of bioballs. If you're using live rock, (and you should be) there is no need for bioballs. All they really do is from a nitrate trap and mess up your levels.

Most aquarist build a corner box to house their in-take and return pipes (or use an overflow system). They drill holes in the bottom of the tank, and then add two glass walls creating a water-tight box in the corner of the tank. This prevents your entire tank from draining when the power goes out or your pumps fail. We tried for a more aesthetically pleasing method. We drilled holes in the top of the back wall on each side. [ Note: If you have a 50-75 Gallon tank you probably do not need two intakes and returns. ] By placing the holes at the top of the tank, we ensured that our entire tank would not be drained in the event of a power/pump failure.

We initially though about placing the hole at the bottom of the tank, as most people do, and then leaving the walls out. The problem with that is, if your bulkheads leak or break, your entire tank will drain into your house. Over 125 gallons of water in your house, plus all the dead fish, is a pretty risky option. By using our method you can eliminate the box, and still protect your house.

Note: I am now selling this tank. I have removed the refeguim on the far left. This makes the entire system more compact and self contained, but the version I am selling won't match the above illustration exactly.