I am planning to keep Apistos.I will use RO water and some leaves to change water and overall environment. My tap water is rock hard.If I use 50-50 RO tap mix TDS will be around 250. I think addition of some oak leaves will help imitate their natural environment too.Now we are in spring and all leaves I can collect from woods are partially rotten. But are they safe to use and is it really important to have leaves in the tank for apistos?