This all depends upon what you want to get out of the system. If you want a large amount of flow, you may be fine. If you have livestock that likes lower flow rates it may be too much.
If your system is doing well, you may already have enough circulation, and adding more will only give a marginal improvement.
If you think that 600 gph might be too much, you can always get something smaller, and get a second one later if needed. Two smaller pumps may even give you better circulation.
