K temp is wrong for fw plants. More like 55-65K would be better.
Need to do some home work on the specific needs of the plants your interested in keeping, not all plant want the same water parameters (kh/ph, etc) and just like corals, not all plants want the same type / amount of light.
Substrate is very important, regular old gravel is not good for most, laterite would be a good idea. I believe that this system has a wet / dry filter? Also not god for planted aquariums, it strips the co2 two efficiently. Perhaps keeping the filter area over filled with water might be a way of decreasing this. A co2 system would be a good addition to address this as well.
Joel