I have one tank about a year old and one about 3 months. I like it a lot, better than my last batch of ada which stated breaking down almost immediately (that was a bad batch I believe, not typical) I plan to change a couple more tanks over to it in the near future
It only comes in one size bag as far as I know
It will do that for about a month and then starts to slow down. I usually dose about 10 ppm PO4 after water changes for the first month, plus the 5-6 ppm it gets from regular dosing per week. This is with high light and hungry stems, slower tanks probably wouldnt need that much but the soil will do its thing regardless. That first month it will zero all that out completely in just a few days. And then say 5 extra for a couple more months. ADA aquasoil does the same thing.