No apology needed - it’s a useful update
My take on any of the BGA products is that they seem to work amazingly in some tanks to not at all in other tanks - including your experience of worsening BGA
Depending on severity of algae and general plant health, you could clean everything thoroughly and rescape the tank
This doesn’t need to involve much additional budget but does involve a lot of time and effort
Unlike Jurijs I prefer to remove as much livestock initially as I can easily net (he’s right about chasing fish being extremely stressful to the point they may die of exhaustion in the following days) - they go into a food safe bin with 1/3 tank water, 2/3 tap and extra Prime (I have extra heaters and small filter at hand)
Then carefully remove plants and place in large bin with tap water and Prime just in case snails or shrimp slip in too
I like to keep the tank fairly clear so I can see what I’m doing so usually have a syphon running when lifting plants to limit water column grunge, and I’ll refill tank as I go along, adding extra Prime re all the grunge
This of course takes much longer than Jurijs method
Once all plants,livestock, hardscape are out, I refill tank so I can “deep clean” substrate - I have a Python System so easy to do in tank, if buckets it may be easier to remove substrate and rinse elsewhere
Move substrate away from glass so you can clean that biofilm (when BGA often sits)
The idea is to remove as much debris from substrate as possible and “turnover” substrate to aerate
Clean glass etc
Then drain as much water as possible
Clean glass again spraying with peroxide (or Seachem Excel etc BUT the fumes are not great so ensure excellent ventilation)
Residual peroxide or Excel are fine for livestock
Meanwhile clean/scrub hardscape thoroughly
Of you have Aquarium Soil, it’s much easier to rescape when it’s as dry as possible - I create a “ditch” zone on one side and use paper towels (or clean detergent free, scent free towels) to remove water that keeps seeping into the substrate free ditch
This is a good stage to leave it over night etc
Meanwhile (there’s a lot of these)
Sort through plants, trimming any leafs that are damaged or full of algae, just trim crypts back close to the rhizome as likely any remaining leafs will melt soon after tank reset, trim roots to 2-3cm (these will act as temporary anchor for plant and usually melt as new roots grow)
Take care when handling plants not to bruise the delicate submerse leafs - I do all of the plant trimming in a clean bin under water, then transfer prepped plant to a third bin
You can also place on trays and spray regularly, cover with cling wrap etc
Then rescape, replant tank
Wait a day (or longer - depending on fish temporary accommodations) than add back livestock
Going this dramatic will usually break the BGA lifecycle for that tank
Though if tank is newly set up you may want to stay with more conservative approaches