help me size new tank for silver arowana

[Fanlie]

Hey all,

I have now 300L tank.
5 bala shark
2 bgk
6 cl
3 pleco

I want to build new tank to L 230x B 70 x H 70 cm. And want to get add 1 or 2 silver arowana?
sump is 150x 50x 50cm is that enough?
in sump - Bacteria house, ceramic ring, zeolite, bioball,mat.

i do each week 20-25% water changer

no need algae scrubber or UV?

 

[ninjastar]

Sounds good but now what about the overflow and return pump.