As you can see the sump is nothing more than a large rubbermaid container.
Holding about 10 gallons of water, the sump also is home for the heaters, skimmer, pumps and some live rock rubble.

Although the additives look like an advertisement, I'm not promoting any brand/product.
(BTW, the bottle facing the wrong direction is Ken Coral Accel.)

The blue/white tube is the drain from the main tank.  The return line is (was) clear and is on the left side of the
picture, just above the red handle of the ball valve.

Hardware in the sump area include:
Main pump is an Iwaki MD-70RLT (the white pad is an air filter)
Two Ebo-Jager 250 Watt heaters
Maxi-Jet 1000 pump (for Refugium)
The Ultralife Skimmer is powered by a Mag 12
(The skimmer is "flange-less" and is a easy to clean)
 
 

As you can see I've reorganized the additive bottles!

The tank is a 30 gallon breeder tank that is home to several types of macro algae.
The large white container to the left of the tank is my make-up water that is dripped into the sump at a
rate of just under 1 gallon/day.  I use a Kent 60GPD Hi-S RO filter for all make-up water.
I also dose kalk water at about 1 gallon per day.

The laundry tub makes tank maintenance almost a pleasure!