hi i recently had a interpet pf4, and had problems all the time, so i took it back to the shop and they gave me a fluval u4, this was the second interpet pf4 in 3 weeks by the way, my first thought of the u4 is its so quiet and just seems so much better, will my tank still be cycled? i took the bio stone things out of the interpet filter and added them to the bio tray of the u4 so does that mean its still cycled?