Hi Robert I am in the process of putting togather a 108 G reef tank and looking torun 1/4" tubing between my living room and garage, 3 lines. 2 lines will be to drain and refill salt water in my main tank. The plumber wants to run copper under the house. Would 3 plastic tubes inside a PVC pipe be betterI’ve had push-fit fittings failed several times under high pressure (especially above 60 psi) for several reasons. Brass, compression…never. Obviously, metals like brass and copper is not good with saltwater so that’s the downside.