Testing depleted Aquasoil

[Patrick_G]

Has anyone had their old aquasoil (or old organic soil) tested? I’m curious to see lab results on how long it stays rich in nutrients. 

[Tihshho]

I've never had it tested, but I more so look at the type of algae growth. With a new aquasoil tank that isn't established I tend to get a rush of hair algae until I get the CO2 balance. Later when the soil becomes more depleted I start to see more of a cyano growth. It's been consistent for me for years and that's generally the sign I use to let me know it's time to swap substrate.