[BLAKEJOHN]

If you are gong to do that. (restart the cycle). I would not do any water changes during the cycle. This will soften the cycle and it may last even longer. And you may not bulid the bacteria level that you want.

Lets see if I can explain this clearly:

Lets say your ammonia is peaked at 8ppm and your nitrite level is at 4ppm. If you leave the water alone you will have enough bacteria to convert all the ammonia and all the nitrites.
Now lets say you do a water change of 50%. That will bring your levels down 50% to NH-4ppm and NO2-2ppm. Now you have just reduce the amount of Ammonia and nitrite therefore reducing the amount of work the bacteria has to do, furthermore reducing the amount of bacteria to be grown.
(these numbers and theory are not 100% accurate but you get the idea)

So I would wait untill the ammonia and nitrites are at zero then do some water changes to bring down the nitrates.