I want to try these plants in my 20g High but the only light I can provide is 15w at this moment. since I know that it is a low light level I was wondering if they could thrive in this setting? I have successfully grown amazon swords in this tank using Excel and they grew to about 8 inches. I have since moved these giants into a 29g. I have been dosing my plants in my other tanks with Flourish and Excel and some Flourish Trace. I would like to know if this would help these plants if I put them in the 20g High.