That's why when you keep Fw tanks with a sandy bottom, you have to keep stirring it every other week or so. In my case, I have borrowing fish, which keep the sand stirred all the time
Never heard that, sounds like BS. I have heard that if your tank can keep a clam alive long term, then your tank is probably too dirty. Saltwater clams are highly photosynthetic. Those would probably consume nitrates. On second thought, the clam itself probably pruduces all the nitrates that thier zooanthellae need.
did that help taimoor? your friends tank is going to crash- so don't use this method in your own tan and if you can i'd print off and article on it and how to fix it and give it to your friend it you want to give those fish a chance