My frag system is completely separate from my main display. My main tank had elevated tin while my frag system had 0.
Acros were rtn/stn in the main display, and moving them to the frag tank almost immediately stopped it and they started recovering.
Similarities between the tanks (things I could rule out):
- Same top-up water
- Same additives (Triton "Other Methods")
- Same rigid pvc source
- Both tanks around 2 years old
- Both tanks use siporax biomedia
It could have potentially been the glass, but tin had gone up between triton tests and I had been doing water changes.
I checked all the pumps and I already used plastic hose clamps. Doing a good clean of my lights one day, I noticed the feet that held the lights on the tank had a small bit of corrosion around a spot where plastic screws hold the feet firm to the sides of the glass. Since then I’ve hung the lights, added metasorb and things took a turn for the better, an acro with no colour for almost 8 months started greening up again less than two weeks after those two changes.