I have two Reeflo Barracuda pumps running on closed loops on a 309 gallon cube. At 4500 GPH x 2 I'm looking at 9000 gallons per hr, or close to 30 times turnover an hour.
The last tank I put together was a DIY 30gallon AIO with two Tunze 6055's and a maxijet 1200 as a return. On that tank it varied due to the controller from 600GPH up too 3,000 GPH