my lastest post this evening.

surprisingly, didnt lose any boraras today. They were still active, but same, all 2 of them are behaving oddly, swimming frantically up and down the tank walls. Both of their colors are now pale but eating properly.

BGA sprung right back after being cleared on wednesday, they are developing slime now.

Newtank,
KH =0 means no buffer for PH swings. This is understood. Nothing new in your post.

Peter,
Drop checker is reading green -> to darkgreen. 3 seconds for 1 bubble too much ? I have increased the airpump back to full strength, probably that explains why i didnt lose any fishes today, but not sure what they are stressed about as there is nothing new i have changed besides those I have listed from monday.

I plan to move the fishes to a 700ml temporary tank with existing tank water tomorrow during my wc while i vacumn the soil again after removing the HG in that area.

question ?
-Do i need to re aclimate them again for a couple of hours before introducing back to the tank as I may need to do a 100% water change tomorrow since i need to plant back the HG before adding water. Is this advisable or should i put it off to avoid shocking the fishes ? and go for just a 3 day black out with good aeration ?

I will wait for your helpful advise before progressing then. Many thanks

eddy,
5-6.6 PH is a range which exhibits my usual PH.

shadow,
it should be BGA as i recognise the green slime on my HG again.