Today we are going to build a sump and show you guys just how easy it is to build a custom sump filter that is not only effective but also easy on the wallet.

When building a fish tank, thorough planning really goes a long way especially when it comes to the sump. So first up is proper planning.

When sizing a sump, you pretty much want the largest tank possible. So measure the space you have for your sump and choose the largest tank that will fit.

This gives you plenty of room to add equipment and ensures the sump is large enough to hold any water that drains from your tank in the event of a power outage or some other unexpected disaster. 10% of your tank volume is considered the minimum sump size for an aquarium.

We have a 50 gallon display tank and are using a 30-gallon rimless aquarium to build our sump. Just about any aquarium will work for a sump: including regular framed glass tanks that are easy to find and fairly inexpensive.

Now we need to think about the baffles. Be mindful of the different chamber sizes and water level when planning your baffles. I like to take a ruler and sharpie to draw on the side of the tank. This helps me visualize the baffle location and water level. You can even test fit your skimmer and other equipment to ensure the baffles are placed appropriately.

When it comes to water level, you want it to be 4-6 inches or more below the top to ensure the sump can hold a little extra water.

Using our handy aquarium calculator, you can easily calculate the amount of water that will drain from your tank in the event of a power outage. Just calculate the amount of water in the area inside your tank that will drain into the sump (basically the area between your return pipes and maximum water level in the tank).

This way you will know for certain that your sump is large enough to hold the water and allows you to adjust the baffle height before it is too late.

In this sump we want a skimmer chamber, a return pump chamber and an isolated ATO reservoir to hold top-off water. Many pre-manufactured sumps include a refugium chamber but we decided to use this space for the ATO chamber instead.

Notice the baffles are positioned close together in such a way that will trap bubbles and reduce any debris from entering the pump chamber which is pretty common practice and generally referred to as a “bubble trap” and should always be placed before the pump chamber.

I have found it best to have your baffles cut with polished edges at a local glass shop instead of trying to cut them yourself. Freshly cut glass can be really sharp and dangerous; by getting it professionally cut you can avoid this hazard and ensure the baffles are cut perfectly to size with straight edges.

When sizing the baffles, you want to have them cut to be about ¼” short on the sides. This makes them easy to place in the tank and gives plenty of room for the silicone to adhere to both your tank wall and the baffle.

Using thick glass for the baffles, ¼” thick or more, is best. This helps when gluing the baffles in place because with thicker edges you give you more surface area for the silicone to bond.

Now the hard part, working with silicone to secure the baffles in your sump.

You need to ensure you get 100% pure silicone that is safe for aquarium use which is generally available at your local home improvement store.

Start with the first baffle and hold it in place using a few pieces of tape. If you need a gap on the bottom you can use some DVD or CD cases; even a 2" x 4" will work in most situations but the CD cases are nice because they are easy to remove from tight spaces and give you a little flexibility in terms of getting the exact gap size you want on the bottom.

After setting the baffle, run a generous bead of silicone up each of the corners and pass over with your finger one time. Do not press too hard with your finger as this can move the baffle around. Using more silicone is much easier than trying to spread a minimal amount. By only passing once over with your finger it will keep it clean and reduce the chances of your baffle moving around.

Once set into place, you need to let the silicone cure for a minimum of 24 hours.

I find it easier to glue one baffle at a time because this ensures the first baffle won’t move around when you’re working on the second one but if you are confident in your baffling and silicone skills, you can certainly set them all at once.

Don’t be upset if your silicone job is not perfect; it simply needs to hold the baffles in place and probably will not be all that pretty, especially your first time.

After the silicone cures, you can always cut a straight edge using a razor blade if you are one for details but nobody looks at your sump anyway and I usually just leave the ugly silicone alone.

After the silicone cures, dry fit all of your equipment to ensure it fits.

We are using the AquaMaxx CO-1 protein skimmer along with a couple of AquaMaxx Media Reactors. We chose to use the Waveline DC water pump which is new here at Marine Depot and are Apex Ready right out of the box. We also added the CPR Sock-It Filter Sock Holder which easily attaches to the edge of any rimmed, rimeless or eurobraced aquarium.

After test fitting your equipment, you want to do a water test to check for leaks and ensure the water flows through the baffles as expected. I usually just run my garden hose into the first chamber and watch the water flow through the baffles as it fills up. Let the entire sump rest full of water for 24-48 hours then come back and check for leaks.

So there you have it folks, a custom sump that is perfectly fit to your aquarium!

For those of you who have reservations about building your own sump, Marine Depot carries the popular Trigger Systems sumps which are pre-manufactured and come in a variety of sizes that are ready to go right out of the box with all the bells and whistles including adjustable baffles, media trays, sock and probe holders, and much more so be sure to check these out.

If you’re thinking about installing a sump, our trained team of aquarium experts is here to help! Don't forget to like, share and subscribe to show your support and to help us bring you more great instructional videos just like this.

Until next time, take car and happy reefkeeping.