Right. Some poeple have found success against dinos with algaefix/vibrant etc but not because it worked as part of a biodiversity-themed approach. In fact, the polyquat algaecide is especially effective against diatoms which are frequently the best competitor to the dinos.
Anecdotally, some people find using Algaefix etc useful vs dinos, but not a very high percentage. Dino-X is a similar chemical that seems to be somewhat stronger/harsher. A higher % of people find Dino-X treatment effective vs dinos (and a higher % report adverse effects on livestock compared to algaefix etc).