I've already done a thread on general discussions telling you about my new 8'x3'x3' which is currently being set up. I'm looking now for some specific ideas/help for areas where I'm unsure and the first one is the substrate.I currently have 16 bags of ecocomplete waiting to be used in the new tank but that is only 320lbs and if I'm looking for 3" depth approx. I'll need much more,about 576lbs total according to the substrate calculator. I'd rather not buy another 12+ bags of EC as it's an expensive product but on the other hand I don't want to risk spoiling the look of the tank by mixing it with something else cheaper as a top layer,unless it looks equally as good. I'm wondering about using something underneath the EC as a base - maybe something like an aquasoil,similar to a Walstad set up,but I really don't know :? The most important thing is that I get things right at the outset as you can imagine with such a big tank,the thought of stripping it down after a few weeks/months makes me feel faint So if I have to bite the bullet and buy another load of EC I will but if you can think of any viable alternatives that might save a few quid I'd be very grateful. Btw,following on from my previous thread we have decided to have CO2 and add nutrients etc. to try to keep something a bit more adventurous and high tech(gulp).So I'll be asking about all that in other threads as we progress,I'm a bit scared but very excited too.