I am new and have 100 gallon FOWLR but an unorthodox setup I have a Fluval FX5 connected to the overflow box with a strainer. I have heard this setup won't work and am wondering why is it because of lack of oxygen? I have had it running 3 weeks and have 3 blue Damsels and all the water parameters are good.Can someone tell me if this setup will work or am I just dreaming. All responses are welcome as I am new and learning thanks