Clean up crew ?

I am in my almost 3rd week of cylcle and i am seeing diatoms forming .
at what pinot should I introduce a cleanup crew?

 

You don't have much to clean up yet. If you do, make sure to add some food from time to time

 

So I should Wait till 5th or 6th week?

 

You should add a clean up crew after adding fish. Wait till your cycle is over then add fish than a CUC.

 

I've always added my CUC before adding any fish. This way the biological filter gets a chance to build up a little before adding fish and helps to minimize the Ammonia and Nitrite spikes. I would wait until the cycle is complete (zero Ammonia and Nitrite) and then wait another two weeks minimum, giving the tank a chance to start to develop some algae on the rocks or glass.

 

Cool ty , I am going to add 1 coral and 1 fish after cycle.