There are plenty of lanthanum chloride based solutions on the market PhophateRX is one off the top of my head, I think Two Little Fishies also makes another. Easy way to get phophates under control without needing extra equipment.
Doesn't need a high flow area, but Phosguard has to be changed as per directions. You need to monitor phosphate levels while bring ing them down every day or so. You may need to change the phosguard every four days until they're under control. Just be careful not to drop to fast.
i have media caddies in each of the overflow. one has marine pure ceramic balls and filter floss in the top chamber. The other had the three IM sponges, but right now it has filter floss and the Phosguard