Vallesneria is not getting tall

[ma2oo]

Hi my val is not growing any taller. The main mother plant has several runners, but they are still about 2 inches tall. Here is a pic
The mother plant is abput 7inches tall but no new leaves.

 

[aqua_chem]

How old are they? What's your tank setup?

 

[ma2oo]

My tank is a 25 gallon with 10 penguin tetras, 4 cories, 1 oto, 1 bristlenose pleco, and 1 german blue ram. 2 weeks ago I upgraded my ten gallon to the 25. Its been running well since I am running a old and new filter on the tank. The val has been in the tank since the beginning of summer. I did move it from my ten gallon though.

 

[20cc]

i have vals with co2 and dosing ferts and they werent really growing fast or "fat" ..and then i put a root tab underneath them and they took off now they are to the top of the tank and halfway over ... my substrate is sand and they perefer a rich substrate

pop a root tab underneath them