If your running a skimmer in the back of the solana or any all in one for that matter, you don't really want a flow rate of close to 700gph. I switched from the stock pump to a mj900 which is less flow and have seen huge improvements with my euroreef skimmer. Same with running gfo passively in the back, probably don't want so much flow through it.
Skimmers are much more effective when they can keep up with the flow rate through the chamber they are in. I personally would stick to below 300gph for a solana. You shouldn't be trying to get as much flow as possible from the return.