So you are ready to build / order a sump!
Now you must make a series of decisions so make it fit your specific needs.
How large should the sump be?
The bigger, the better. The larger your sump, the more water volume you’ll be adding to the total system, plus it will be able to hold excess water during a power (or pump) failure. No floods, no wet flooring!
How do I decide the size?
Look at the area within the stand, taking note of any
obstructions that are part of the construction of the stand. Note the
hinges as well, as they can become a problem. How will you insert the
sump? Through the front opening, or perhaps the rear? You may be able
to remove the “style” (the upright piece of wood) from the front using
a square-head screwdriver, giving you full access to drop in the sump.
The width of the sump should be the space from the front of the stand to the back, less 1”. Leave yourself a little room to adjust the sump into position.
Height is varied, but typically 16” is plenty. If the sump is too tall, it is very difficult to access things such as pumps, heaters, probes, etc. It might make it impossible to insert a skimmer in a tall sump, as there is only so much room under a tank. 16” tall works nicely, usually providing at least 10” of space to manipulate things. If you plan to implement a refugium, you’ll need to leave room for a light as well.
Measure the opening's length (red), height (green) and
take note of obstructions (hinges, circled)
How do I determine the size of each section or compartment?
Leave enough room for the skimmer and pump, by obtaining the ‘footprint’ size of the skimmer. Find out how deeply the skimmer can sit in water, according to the skimmer’s manufacturer.
The refugium needs to be large enough to grow macro algae and hold some live sand, but it doesn’t need to be huge.
The return section needs to be big if possible. This section varies due to evaporation, so the more water volume it holds, the longer you can be away from your tank and still have enough water to avoid burning up the return pump. It should be large enough to run for two or three days unattended. If space is at a premium, an automatic top-off system with a float switch will protect against evaporation issues.
How tall should the baffles be?
Once the water depth for your skimmer has been ascertained, the baffle height can be set accordingly. If the skimmer needs shallower waters, I still recommend making the skimmer zone deep. By having more water around the skimmer, it allows the bubbles time to rise and pop, so they won’t end up in the display tank. Put the skimmer on a short stand so it still meets manufacturer’s recommendations. Make sure that the skimmer sitting on a stand will still fit within the cabinet area and permit removal of the collection cup!
Average baffle height is 9 to 10”.
How wide should the bubble trap be, and how high off the bottom is the middle baffle?
1” of space between baffles, with the middle baffle 1” off the base of the sump. 1.5” - 2” works fine as well. A carbon tray can be incorporated between the baffles if desired.
How deep should the refugium be?
12” works nicely, because 2” of sand takes up some space. The baffle should be 13” or 14” tall, with teeth cut 1.5” (vertically) along the top edge. The teeth prevent the macro algae from going into the next compartment, and helps keep snails in the refugium.
What is the best layout?
There are a number of ways to configure the compartments, including some comments:
This is a simple layout that keeps the flow going in one direction. One objection often voiced is that “you don’t want to skim out the nutrients in the water going to the refugium.” This isn’t possible to do, unless every drop of water had to go through the skimmer to get into the refugium. Most of the water runs right past the skimmer! Even with a very weak return pump, the water pumped into the skimmer is only a portion of the body of water traveling into the next compartment.
Benefit - all baffles are the same height.
In this situation, the two outer compartments receive their water from two sources (or one supply line that has been split), and pour into the central compartment.
Benefit - Refugium wall can be taller, and the amount of water flowing through it can be controlled with a ball valve.
This is a bad idea in my opinion, because the micro fauna (copepods, amphipods and more) that you hope to send up to your display tank as food are going to be skimmed out of the water before they ever reach the Return zone. If this is your layout, have the refugium drain via PVC pipe directly into the Return zone, bypassing the skimmer zone.
Benefit - none.
What kind of acrylic and glue do you use, and where do you buy them?
¼” Acrylite FF for most applications. The glue is a product called Weld-On, that literally melts the two pieces of acrylic into one piece, forming a very strong bond. Weld-On #3 is fast drying (less than 60 seconds), #4 is slower (less than 5 minutes), and #16 is for patching.
#3 and #4 need a “needle applicator bottle,” and #16 needs a nozzle for better control (found at most hobby shops). I use a glass turkey baster to suck up #3 or #4 (from the can) when filling the applicator bottle.
These products can be found at Regal Plastics in Texas. Check the Yellow Pages for “plastics” to find a vendor in your area.
Do you have any further suggestions?