I've had a red tiger lotus for 2 or more months in my 20 gallon and it only grows 2.5in off the substrate. I bought it at 2in. The leaves only get from dime to quarter size. It is under T-5 bulbs that has had coral grown under before. It is the only plant not growing in my 20 gallon. All of my other plants grow like crazy. I also have a dwarf water lilly that has a new leaf at the surface every 1 to 2 days. This is a low tech aquarium with no dosing, but everything grows like weeds in there. Is there anything I'm doing wrong?