After three weeks of treating the Shrimphaus with Tetra AlguMin in an attempt at chemical control of black beard algae, I can confidently report that monolinuron, the active ingredient in AlguMin, has absolutely no effect whatsoever on black beard algae (BBA, black brush algae). The algae is as healthy and bushy as ever, does not scrub off even with vigorous rubbing, and may even have grown a little thicker. I can’t really tell whether monolinuron was effective against green algae, as that wasn’t a major problem and so I wasn’t paying careful attention. Certainly there was no visible green algae at the end of the treatment but there may not have been much in the first instance.
Monolinuron is safe for shrimp and snails
When used as directed at full strength, there were no adverse effects on either the zebra thorn snails, or on the cherry shrimp. For a black beard algae reset, sterner measures are needed.