Thanks so much for the help, guys! This is really appreciated!
Bruce and Complexity, I want to change the substrate and the hard scape of the tank for a start. I have used playsand as I really love the look but am finding that it's just not working for me. It is constantly looking too dirty. I'd like to go for something far more plant friendly as well.
As for the structure, my tank is quite tall, so I want to try and build it up more at the back. Because of the depth, I am worried my lights aren't adequate (4 30w tubes). Many of my plants are putting out roots halfway up and are just, well, not looking at all healthy. I have a manual CO2 delivery system and am watching to make sure there is always gas in the tube to be absorbed but still plants are dying off.
When I set the tank up, I (mistakenly
) believed I would be more interested in the fish, but as I get more interested here, I have other ideas for the tank and my focus is more on the plants and finding ways to keep them healthy. I will probably review my filter set up after I get the hard scape and substrate back together. I've been reassured by my LFS that it's adequate for the tank I have (I love that I have an honest manager who doesn't always try and sell me stuff! <3 ) but it just seems there isn't enough...I don't know, life(?) in the water? Not enough sparkle? Does this make sense? Something doesn't seem right even though my tests for ammonia, nitrate and nitrites are all fine. The area I live in has ridiculously high pH water (usually about 8.2 from the tap!) so I use RO water for most of my water changes now.