I'm not sure it matters which amino acids are dosed. They are all a good source of N.
IMO, it is possible that aspartic acid may be better than the others, for reasons I outlined twenty years ago:
All reef aquarists are versed in the fact that such organisms remove calcium and carbonate from the water column in order to provide materials for calcification. Exactly how calcification takes place, however, is rarely considered.
reefs.com
"Interestingly, the apparently large need for a particular amino acid (aspartic acid) to synthesize these proteins is satisfied by external sources, not by either the coral itself or the zooxanthellae. For this reason, it might be interesting to see what added aspartic acid does to calcification rates in reef tanks."