return pump

I have been thinking of getting a bigger return pump for my 40 breeder but don't know if it would be worth it. I am currently using an ocean runner 2500(625g/h) with a hang on lifereef single overflow. The pump is ran to a scwd using 3/4 pipe., with 7 90's and 2 45's on each line off of the scwd, with 3 foot vert. and 3 foot horz. of pipe. I was thinking of going with an ocean runner 3500(900g/h). I don't know if this would be too much for the overflow or not. I have played with the head loss caculator but it doesn't have this pump in it so the figures are not accurate. I was also going to tee the return off to go to a refugium but know that this has now effect on the overflow. I thank all for their help.