I bought a Ludwigia Repens about 5 months ago, or at least thats what i think its a Ludwigia Repens i don't really remember. and the base of the plant is slowly getting thinner and its all falling apart. Other than that it seems fine like the leafs seem happy, but its just falling apart at the base. I just have the stock lighting and some API plant food. Is there any way i can stop it from deteriorating at the bottom?