Hi, I have a 220 litre tank (200l with all the substrate etc. in it - pic attached but not very good) As you can see I am trying to plant it up. It has a substrate of very fine white sand, bog wood, pressurised co2, and two T5 (1white, 1pink) lamps. Could someone recommend a decent liquid plant food fertiliser to use please? PS the fern at the centre back of the tank is just the backing picture.