What is your lighting? If you have higher lighting and are using CO2 you really need to be dosing dry ferts that provide all the macro and micro nutrients plants need. Higher light and CO2 increases photosynthesis which means plants need more nutrients. What are your nitrate and phosphate readings?
I'll list some of my favorite red plants but considering you have a larger tank getting both large and small leaf plants actually look better. When you use all say small leaf plants they tend to blend together and none of them stand out. Here's an example...
Aquarium Advice - Aquarium Forum Community - Rivercats's Album: 220g 8-9-13 - Picture.
Red plants:
Rotala Mini Butterfly (very small leaves)
Ludwigia Senegalensis (small leaves)
Ludwigia Atlantis (med leaves)
Ludwigia Glandulosa (large leaves)
Rotala Wallichii (small leaves)
Rotala Macrandra (med leaves)
Rotala Magenta (small leaves)
Rotala Narrowleaf (small leaves)
There are a ton of red different red plants and the above are just a few.