See this thread for filter sizings:
viewtopic.php?f=9&t=30145The XP3 and the 2217 are both undersized for the turtle tank. They both handle about the same size tank 55-60 gallons. Your best bet is to figure out a way to use both of them or upgrade to a larger filter.
You shouldn't be doing water changes during the cycle. It just prolongs the cycle and kicks off mini cycles. You can actually prevent your tank from cycling if you do enough water changes. Remember your turtle can climb completely out of water unlike fish.

's aren't nearly as sensitive to the ammonia as fish. It'll take from a few weeks to a month for your tank to completely cycle. You should do regular ammonia readings. When the ammonia drops to 0, start taking ammonia and nitrite readings. When ammonia and nitrite are both at 0 and stay that way for a few days, your tank is fully cycled. At that point, you'll need to start taking nitrate readings. Nitrates will always climb. The purpose of the regular water change is to keep the nitrate levels in check. Don't add your fish until the tank is fully cycled. Your turtle will be fine. Also, no filter maintenance after the first few days of the cycle. The bio filter needs that time to build up it's bacteria colony.
Don't add any biological supplement or water conditioner to a new tank no matter how convincing the wording on the packaging is.
That thread I posted earlier lists steps for an "optional" or new tank setup. The first few days with your new tank, you want CARBON in the filter, not purigen. Carbon will remove chloramine. We don't care about chlorine. Chlorine isn't used by most water municipals and even if yours does use it... it will evaporate out by itself within 24 hours or so. Aeration of the water (the running filter) helps speed up the chlorine evap process. What we care about is chloramine and Purigen does not remove chloramine... carbon does. You want to run your filter with carbon for the first day or so to pull the chloramine out. Once that's complete you can put your regular filter media (switch to purigen at this point) back in (again see that thread for suggestions) and leave it alone. No cleaning of the filter during the cycle once you put the regular media in.