After months of on & off taking care my tank, now it looks better. In between has problems arisen, such as lack of Ferrum(iron), Calcium and etc. For Iron deficiency is pretty easy to spot on the young leaves turns to white with green veins, just dose with liquid iron or iron pallet push in the soil. And Calcium is a bit hard to tell how much to dose in a week, because plant does not need so much to grow, but for snail use it as building the shell for its protective layer. I did an experiment on stop supplying Calcium for a week or 2, then immediate all the shell of snail turns to white(shell detoriation), the following week onwards keep supplying Calcium, then the shell started build a shining and transparent healthy layer. In this small experiment tells that Calcium is important to keep snail in a healthy condition in the tank. So far each week dosing 1 teaspoon of Calcium Chloride in my 122 litres tank without any problems. Read more about Calcium Chloride at http://en.wikipedia.org/wiki/Calcium_Chloride
