Im currently running diy co2 and used pool filter sand as a substrate, im on the fence between adding some sort of liquid fertilizer or adding some different substrate under the sand . I am planning on kinda "remodeling " the tank right away and want to know it its better to just stick with the sand or if putting some fluval stratum under the sand would be better , also if i went with the fluval is it going to change the perameters of the nitrogen cycle in the tank ? I would imagine there would be some crazy leaching going on for a month or two ? I dont know .. liquid ferts sounds way easier but seeing how im redoing the aquascape it wouldnt be too hard to put some different substrate in .. i would just pull all the fish and plants then move all the sand to one side, repeat with the other side then put everything back where i want it . Either way let me know what yall think !