[plamski]

I have CRS tank with Aquasoil I 14-15 months old. I use RO for water changes and don’t count on buffering effect of the substrate. Do I have to replace still Aquasoil ? What is the reason if I have to?

 

[GeToChKn]

Mostly you replace it if you count on the buffering effect of it. If you're not using it to buffer tap water, probably not a big reason to.