I am familiar with the Sunleaves 600 GPH air pump. The problem we've had with them, is that the supplied hard black air divider (manifold) is very brittle and the vibration from the pump through the supplied short connecting tube over time causes the manifold to come apart (break).

As far as the amount of air required to be pumped through your fish tank water in order to have good aeration, that particular pump is good for about 100 gallons of fish tank maximum, in my opinion.

In order to get the DO level we require, we are now pumping 950 GPH of air into a 120 gallon fish tank. With the addition of the water conditioning tower, we may stop aerating the grow beds and decrease the air going into the fish tanks. If so, then that 600 GPH number for 120 gallon FT looks about right. We will be testing it to find the optimum number of air GPH to water gallons in our system.

This is all about reducing our energy costs without compromising on the operation of the system.

We have learned that it is a good idea to place a check valve in the air line to prevent water from siphoning back into your air pump when turned off, if it is located at a level below that of the water.

Oliver