Hi, I currently have a low light 1.25w per gallon tank, and I am having trouble keeping my plants thriving. At the moment, they are starting to go yellow with brown spots and are getting very spindly with no leaves growing at the bottom of the plant stems. Here is my tank setup: 180L tank Sand Substrate 1.25w per gallon lighting Tropica Plant Nutrition+ Capsuals inserted into sand at base of plant every 4months Tropica Plant Nutrition liquid fert, 10ml per week (was previously adding 5ml per week) Seachem Excel 5ml per day These are my plants: Vallisneria nana Hygrophila corybosa Hygrophila polysperma Anubias barteri var. nana Every thing was growing really well until about 6 weeks ago. I will list out the problems I am having: The Hygrophila polysperma's leaves are turning yellow with dark brown / black spots. The leaves at the top of the plant remain lush green, midway down the plant are the yellow leaves. At the base of the plant many of the leaves appear to be rotting and / or melting. Vallisneria nana - has actually been doing very well, and has established itself throughout the tank. However, now the original leaves are falling apart, as though the leaves have been ripped in half. They are also covered in some black algae. The vallis is also starting to thin pretty badly. Hygrophila corybosa - did wonderful, until it reached the top of the tank. It is a similar story to the polysperma. The leaves at the top are lush green, the mid-stem leaves are yellow with a good number of them melting away. There is some black-algae on some of the leaves. The bottom 1/3 of the plant stem has no leaves at all. Anubias barteri var. nana - I just learnt that this should really be attached to rock or wood. I have mistakenly planted it into the sand substrate. This hasn't grown much, and recently a lot of the leaves have turned dark. The plant is now starting to look as though it is been eaten by snails - though this isn't the case. I really don't want to start getting into CO2 injection or adding a soil substrate. Hence the reason I went for low-light, low-demanding plants. However I'm clearly having a lot of trouble keeping lush growth going. So any tips and suggestions would really be welcome!