Good Evening AKA,

Does anyone have experience using "Erythromycin" in aquarium's with live plants.  I have annubias, hornwort, and Vallisneria spiralis and javafern.

Please post I need to treat a 50 gallon tank heavily planted,

Best wishes, thanks in advance,

Jim Langan, AKA Webmaster

Here someone says it is safe with plants: https://www.reddit.com/r/Aquariums/comments/s0wxe0/erythromycin_treatment_and_plants/ Same here: https://www.aquaticplantcentral.com/threads/perscription-erythromycin.58678/
But I expect it will wipe out the hornwort all the same.

Good Evening AKA, Definitive Updates,

2022-02-05; Update:  I treated my heavily planted 55 gallon tank, which was being taken over by "cynanobacteria"  with API "Erythromycin".  I used 3 packets a light dose, this is normally to treat 30 gallons.  After 7 days the tank is virtually clear of bacteria and the plants all look great. All plants including  annubias ( both large and small variety), hornwort, and Vallisneria spiralis and javafern were unaffected.

2022-02-12; Update: Cyanobacteria is 100% eradicated, no ill affects to any higher order plants.  I will perform a 50% water change and determine if there are any re-occurrences.

Best wishes, thanks Tyrone!

Thanks, Jim. I am also have some cyano issues and will try this myself.

Is the brown film I get on the sides of my tank cyanobacteria?  If not, what is it?
Thnaks

Brown films are likely diatoms, IMO.
Diatomaceous films are eaten by many species of fish and invertebrates. Otocinclus and Cherry Shrimps are examples of such creatures but it often merely represents a stage of ecological succession as "pioneer species" and will eventually be displaced as a tank matures over time.