Usually for a tank this size, most people would recommend a sump. However, some use canisters and fill them up with reef rubble lr
for filtration. Sumps do have advantages though:
More water volume for higher bio loads
A place to hide your equipment, heater, pumps, etc.
You can add lr
rubble to the sump for natural filtration (Berlin method).
The cost for a sump is significantly higher than a canister, but it is worth it for a tank your size. You could DIY
one, but it will need to be built accordingly to prevent any problems. What I did was buy a 125G wet/dry unit off of Ebay for $160, which came with the tank, pump, overflow, and hoses for connection. I threw out the bioballs, and replaced with reef rubble for filtration.
It all depends on what you want, and what works for you. Everyone here has a method that works for them. I like the sump because you can hide everything under the stand, and it is easier to add things such as calcium rather than directly in the tank. HTH
Also - If you don't already have one, look into getting a good skimmer for your tank. Don't get one though until you decide if you want a sump or not as they make different models (HOB
, and in sump).