Following @Syntax1235
Your problems are very familiar. I've been having the same thing plague my tank for the past year so it will be interesting to compare notes. Very simple system with slow STN. No pests seen so I'm wondering if I just have a virulent strain of bacteria. FWIW I pulled out all of my Siporax (similar to matrix) and it seems to have helped. That said I've tried several things so it's hard to pin down just one.
Part of me thinks @markalot is on the right path. I can't say I remember issues with Alk below 7. Hopefully more nutrients will help you as well.
Your problems are very familiar. I've been having the same thing plague my tank for the past year so it will be interesting to compare notes. Very simple system with slow STN. No pests seen so I'm wondering if I just have a virulent strain of bacteria. FWIW I pulled out all of my Siporax (similar to matrix) and it seems to have helped. That said I've tried several things so it's hard to pin down just one.
Part of me thinks @markalot is on the right path. I can't say I remember issues with Alk below 7. Hopefully more nutrients will help you as well.