Which anchors to use for submerged (under water) assemblies.

I am mounting a submerged assembly using a rectangular plate. Using the Hilti program, there are several solutions using kwik bolts but none with chemical based anchors. This is to mount a 5000 lbf weight assembly for continuous service as part of an water intake piping system (which is under water). With the bolt pattern I am proposing a Kwik Bolt TZ2 - SS 316 3/4 (3 1/4) hnom1 was recommended. None of the chemical based anchors were eligible solutions. For a permanent mounting of an anchor, I typically prefer the chemical anchors to the mechanical ones. Am I doing something wrong????