A: NO! Bravo Systems allows only our own Propylene Glycol solution as an interstitial fluid. Using a brine solution or colored water will void your product warranty. The very idea of using brine as an interstice fluid was thrown out by Bravo for use in Double Wall sumps because brine would potentially accelerate deterioration of steel/stainless steel components that come into indirect and direct contact with the brine. This includes penetration fasteners, bolts, flex-connectors and band clamps. Propylene Glycol helps prevent the liquid from freezing within the interstice. Additionally, if the brine solution were to leak out of the wall it could also accelerate the corrosion of other metallic components within the sump.