sven, all of us here are not trying to put you down, but trying to help you gain a healthy and happy tank, last night i told someone else this same thing, :
we are here trying to help and have NOTHING to gain or loose by answering you, except the time it takes to respond to you, unlike th lfs, there is a wealth of knowledge here that can gain ZERO from you, so our views will not and canot be influenced by personal gains of any type, so you decide what you want to do, but alot of people have offered you some good advice, and most(if not all) of those answerrs were the same so you do the math are we tying to help or not?