Breaking it down into simplicity really does help. I find alot of times researching, everyone is so scientific about it and I don't even know where there beginning. Thank you!So tou don’t need to drill the tank to have a sump. You can use a hang over the back syphon and over the back return lines.
the “sump” is the filter- a basic sump usually has filter socks of filter floss/ sponge, skimmer and a return pump. The water from the tank “over flows” as the return pump pumps it back into tank.
a sump allow you to add thinks like reactors for carbon/ gfo/ or some other media. Or to plumb in UV or any equipment is easier to add to your system.
many sumps these days have built in refugiums- but it doesn’t have to be in the sump- can hang off tank or hang off sump but it’s bacically a safe haven for macro algae’s when your using macro algae to help with Nutrient control.
Hope this helps -