SL-Aqua Z-2 Aquarium Plant Protector Review

My search for a whole tank treatment for black beard algae has been on-going for 9+ years. I'm aware of spot treatments using Seachem Excel and hydrogen peroxide, but I've yet to find anything that eliminates BBA permanently. Overdosing Seachem Excel does eliminate a lot, but the BBA comes back every time suggesting some BBA is surviving the treatment.

Most recently, I tried SL-Aqua's Z-2 Plant Protector which, on the label, claims to treat BBA. The instructions indicate that if the first treatment doesn't work, a second treatment of double the dose can be used. My observations after 2 weeks are:

1. The first regular dose didn't eliminate BBA. It also killed Hydrocotyle tripartita and caused the leaves of Ranunculus inundatus to curl. Shrimp and fish were unaffected, but multiple assassin snails were killed.

2. The second double-dose didn't completely eliminate BBA either although some was eliminated and growth seems to have slowed significantly. This time it killed some frogbit and melted the leaves of Hydrocotyle leucocephala. Shrimp remained unaffected, but 2 otocinclus died within days of the dose. I also lost 2 more assassin snails. I imagine there would've been more, but prior to the dosing I removed many.

Overall, I'd say this product is partially effective against black beard algae. However, given the plant and livestock deaths, I wouldn't even recommend it as a way to eliminate BBA or any other algae. Maybe, just maybe, it could be used in a tank that is so far gone that you're going to toss all of the plants and do a reset anyway. I would, of course, remove all livestock first.