big skimmer requirements buy or DIY?

[e46er]

So this doesnt really have anything to do with reefs but im posting this here because i figure this section will have the most traffic of people with knowledge on large skimmers

my buddy is moving at the end of the month and has decided to convert his 220 discus tank to a predator tank he was talking eels or triggers ect now what are reccomendations on skimmers for predator tanks over 200 G??

buy a skimmer or DIY he's fairly handy and not rich so he was leaning towards a DIY


thoughts sugguestions??