Flow vs turn over

[rohnds]

What is the difference between flow and turn over? To be precise, what is the different benefit of flow and turn over? I have heard that SW tank require anywhere between 10 to 20 times. I have 70 gallon tank with Fluval 403 (317 GPH) and my water pump from the sump at 1200 GPH. This is a total of 1517 GPH. That is a total of 21 times. Would increasing the turn over by adding another pump have beneficial effect to the tank.

Right now, I have two 505 powerhead at opposite side of the tank. These two powerheads aren't powerful enough to elminate all dead spots in my tank. So I am market of better powerhead.

Rohn

 

[SALTY WATERS]

Flow would be the measurement of GPH added up from all circulation sources
&
Turn-over would be the measurement of how many times the total volume of your tanks water is cycled through the circulation sources.

You pretty much answered yourself with your calculations... though to get a true reading of your turn-over you would have to take into consideration the total amount of water volume lost due to LR and equipment etc.

As for benifits both pretty much are the same, the more you have the less dead spots, less hot/cold spots, inhibit certain types of algea from growing, better oxygen/gas exchange etc...