Have a very slow leak from one of my valves, thinking of replacing both as the boat is at least 15 years. Looking online it appears to be the Leafield C7 valve. Found the same ones the boat has, made by AIRE, on the scadden website for $29 each, but also saw the same valve made by NRS for cheaper. Assuming they are compatible, but has anyone used one of the NRS on your outcast? Also, i saw a video scadden made showing how to repair valve seal with aquaseal? Is a valve leak usually the seal/gasket? Or multiple parts that can go out? Thank you for any help.