Model G - modified

Kevin, one of our DFWMAS members, requested a large sump be built to go under his new 180g Oceanic reef tank. He wanted a large refugium, room for a Triggersys Protein Skimmer, space in the return zone for propagating frags, probe holders and more.

This webpage will contain various stages of the sump being built to help those of you that prefer to build one yourself one day.

A flat workspace is a must!

I built this platform to maintain a fully flat work surface, and this helps create nice seams.

As you can see, the sump assembly fit nicely.


I start by gluing the ends and internal baffles to the back panel. In the image above, the project has been flipped to glue everything to the front panel.

The bubble trap is glued at once, and weights are placed on top to get the best seam possible.

This refugium is larger than normal, and was patially built before being bonded into the sump itself.

While the sump was on its side, I glued the probe bracket in place, as well as a bubble tower. Both of these are in the skimmer section.

This bracket is for a float switch that would be used to automatically top off any evaporated water with fresh RO/DI water.

Next, the entire sump is set on its base, and glued to that.

Every 8", I insert a .18mm accupuncture needle between the sump and the base. Next a shim is slipped under the base sheet, to maintain a snug hold of the needle. Once all the needles along one side are inserted and snug, I then apply Weld-On #4 into the seam.

After waiting about 30 to 45 seconds, I pull out each needle, which allows the top piece to settle into the solvent-softened material. Any Weld-On that puddles out will be routed away later, leaving a nice edge.

Next, each shim is tucked in slightly further to press the base tightly against the upright wall, to remove any airbubbles in the joint. Above, you can see a few bubbles, but once the shim was pressed in, those worked their way out of the seam.

Next, the entire sump was inverted, and now the top piece is being glued to the sump. Using the needles and shims, a good joint was made around the perimeter of the sump.

To avoid creating a vacuum within the sump during curing, I drilled a hole in the sump and platform before gluing. This allows air to vent in and fumes to work their way out. I made sure to drill the hole far enough inside the top panel to allow for a 2" flange later when it was ready to be routed.

Done and ready to use

A day later, the sump is routed along all edges, and the top opening is created, leaving a 2" lip (flange) around the top. In the above image, you can see the hole for a 1.5" bulkhead. Water will exit this hole and be pumped up to the tank with a Sequence (external) pump.

This little box is something new. It is mounted inside the refugium compartment, and the hole is for a pH Controller probe. A calcium reactor will drip its effluent into this box, and the probe will measure its pH at all times. The box will overflow quietly into the refugium section, and any excess C02 will be absorbed by the macro algae growing in this section.

I like this shot, mainly because of the shadow cast by the sump.

A 1.5" stand was created for the skimmer. Triggersys skimmers can run in 8" deep water, but this compartment is 9" tall. The stand will elevate it just enough to maintain efficiency, and yet not interfere with the collection cup's removal within the aquarium's stand.

Here are a few images of the sump in front of the new stand.

The sump is 48" x 20" x 16", with a 20g refugium section.


The stand was built so the back upright could be removed, allowing the sump to install from the back.

The sump was inserted with the foam sheet beneath, and the stand reassembled.

The skimmer fits, the return pump is in place, and plumbing is next.

Here's how Kevin plumbed it in. Two drains from the tank are connected to a horizontal pipe with two points that can drain.

The right side: Tank water drains into the refugium. The ball valve controls how much flows into this compartment. Note that the elbow is installed so that water will pour out at the water level in the refugium, with the fitting half submerged. With it not fully submerged, air can breathe out of the plumbing. The more the ball valve is closed, the less water can drain out. Any excess water will simply travel across the horizontal pipe to the other drain (in the skimmer section).

The lower plumbing fitting is set up for the return pump. An elbow inside the sump sucks water from the bottom 1" of the return section, to avoid sucking in any air. Using unions to connect the pump allows it to easily be removed later for maintenance. Even some of the drain plumbing has unions so that sections of pipe can be removed if necessary.

The drain line going into the skimmer section is set up to drain into the bubble tower. Water will pour out the base through the teeth, behind the protein skimmer (not pictured). The light is a 6400K spiral compact fluorescent bulb to light the refugium. This size refugium will need two bulbs to provide adequate lighting for the macro algae growing in 20g of water.

Email Marc

Melev's Reef