Bleach is the way to go.
It takes time and patience.
Doing mine right now. I'am in on the 10th day.
Day 1: 25liters water mixed with 7,5 liter bleach
Day 2 : Black gunch is floating up
Cleaning the part inbetween soaking to give the bleach a new surface to react.
5 days later .
I changed the bath for a new mixed load of water and bleach.
Yesterdays result . I'am almost there...
Mixed the 3rd batch and it is bubbling like crazy.
It takes time and patience.
Doing mine right now. I'am in on the 10th day.
Day 1: 25liters water mixed with 7,5 liter bleach
Day 2 : Black gunch is floating up
Cleaning the part inbetween soaking to give the bleach a new surface to react.
5 days later .
I changed the bath for a new mixed load of water and bleach.
Yesterdays result . I'am almost there...
Mixed the 3rd batch and it is bubbling like crazy.