Basic water flow info.
 

Ok, I know this has been covered probably a thousand times, however I couldn't find any threads. So if you want to point me the right one that would be awesome.

This is my first reef I will be drilling a 40g breeder using herbie overflow to a 20g long sump/refugium. My question is two part.

1) Suggested total water turn over rate GPH.
2) In tank powerhead flow rate GPH.

Your help is much appreciated!

To Reef Central
3-5x turnover through the sump

powerhead or closed loop flow:
10-20x turnover for softies and some lps
20-40x turnover for lps and some sps
40x + sps

most corals can do fine with more or less flow though, these are just some guide lines