Changing substrate in established tank

[crip_tic]

I used Tropica Plant Substrate with Fluval Shrimp Stratum on the top. About and inch of soil and half an inch of Fluval approx. 1 Year on , strong plant growth with no added ferts. My tank was sitting with the cycling bacteria added for about 8 weeks before shrimps went in. pH has stayed at 7.5 on rain water which is just below 7 usually. I didn't really seem to get an ammonia spike when I set up and no discoloured water (I added water in slowly over a saucer). I later added Purigen but didn't really need to - probably won't bother in my next tank.