Can I quickly ask if an SOW-3 would be too much for a 5g? I was looking at these pumps and was about to post this question. It's 16"L x 6"D x 11"H. I heard these are super powerful pumps so if you're saying an SOW-4 is good for the OP's 30g then I think the 3 will be too much for my tank.You can run sw-8 at lowest setting otherwise SW-4 should be okay