PH above 7 is basic, not acidic. Concrete is basic, so its possible that this is just the result of water coming into contact with the concrete packer, and is not necessarily the result of dissolution. Not sure where the epoxy resin would be in your keel, as the builder would likely have used polyester. Epoxy is fairly inert, so wouldn't be "hydrolysing". Some boats, like the Alberg 30, were filled with iron tailings and bedded in concrete filler, rather than lead, in which case you would see rusty water weeping out. Not sure whether this is the case for the Aloha, but in any event, the biggest concern here would be a water-logged keel freezing and expanding in winter, causing cracking of the fiberglass envelope. Concrete is hygroscopic, so once wet in an encapsulated keel would likely never dry out. This is a fairly common problem for any encapsulated keel with water infiltration, and unless there are visible signs of damage to the skin, I wouldn't worry about it - boat's probably been like that for years and still works, so just enjoy her.