I was going to go substrate-less on 8 tanks I have that need setting up. Then the Amano book arrived today. It has made me desperately want lush green carpets and all the benefits of plants behaving like secondary filters in the tanks. I am thinking about things I could use in the substrate. I don't want to mess with my water params ph etc - they look so good now now after cutting with RO. I'm thinking of using the following: Bacter 100, slow release ferts, bonsai pumice, ph inert gravel (or sand?), maybe a little akadama? I'm thinking a layer with some bacter & ferts, then pumice/akadama mix, finally a cap of gravel. I looked at ADA penac W - is it worth including? Is there anything else I should consider adding from the getgo? Ferts - how many will roughly I need in a 24L tank & will they cause ammonia spikes? I am clueless & confused about ferts use. Can anyone recommend a decent fert to go under the gravel?