question for diy rock makers

[dabandit]

When we do masonry around wet situations we use hydraulic cement because it doesnt contain gypsum,i've used hydraulic in ponds with sucess but im not sure how it would affect a reef. In researching recipes i;ve found no one uses hydraulic. Ok anyway......non hydraulic cement due to the high gypsum content is prone to effloress which is actually basically salt leeching out,now mixing the cement with rock salt then placing it in a marine environment in theory should make this worse. I would love to make some,but first I'd like to hear from users of this diy product to see if a;your salinity is rising or b youve noticed a white buildup on your rock or c if anyone has used hydraulic cement in a reef tank