whats the most GPH i can't put in my return pump?

[Natecespinosa]

I have a JBJ nanocube 28 gal. So it has two returns, on both left and right sides of the tank. I have replaced the them both over time. But nothing over the original 266gph that come in them for a total of 532 gph in the tank. I want to ramp it up. I want to go with two 315's or 370's. Is that way to much? Will they suck the water out of their chambers faster than the overflow can produce?

I also have a Hydor koralia 425 gph in there but i seem to not as much flow as i need. I can't get ride of this red slime algae. I can tell by my coral like the torch and hammer that the flow in the tank could be better. But does anyone know about the maximum GPH i can load my tank up with?

 

[Aquarian]

I think your already there. You may even have too much already.

 

[kbuser92]

+1. Its more about placement and direction than amount, though its possible to have too much or too little. You could add 315's and several more koralias and if they're not aimed strategically, you won't have enough flow. Before you add or upgrade, I would mess around with your aiming to try to minimize dead spots and I believe it can be done with what you have in there. But to answer about running your chamber dry, check what the overflow is rated for and don't exceed that. Most of the time they will use smaller powerheads to ensure that it works smooth with room for error.