Increase the your rig's buoyancy using floats or float arms | Interceptor121 Photography & Video Workshops
Amazon.com: DIVTEK Float Arm D52-160 Diving Buoyancy Arm Bracket with Nauticam Bayonet Mount for Underwater Diving Tray Video Light/Strobe Float Arms (D52-160) : Electronics
Float Arm 89x180mm (Adjustable) - Kraken Sports - Kraken Sports