Red Sea 250 v3 sump upgrade advice ?

[Nanolifeuk]

I am a long way from setting this up. But want to plan this thoroughly.

From my understanding, the new v3 sumps have a chamber before the protein skimmer to house a refugium. But what else should I put in there?

reefmat 500
Purigen/ chemipure carbon
Bio media
Rsk 300 skimmer


and then ? Also unsure of best return pump upgrade if anyone can recommend?

 

[Nanolifeuk]

Co2 scrubber /reactor . UV steriliser. There’s so many options and not sure which to prioritise.