3 layers of p4 mesh PLUS one layer of gutterguard is too much for a Sedra 3500. My Sedra 5000 wont even do that. My sedra 3500 has 3 layers of P4 and kicks butt. I still use it in my live rock curing vat and occasionally in my grow out system. I would leave the gutterguard off. Just my 2 cents worth. The Sedra 5000 on my modded G3 won't even drive 4 layers.