ZWO says there are three filters, Dark, LP and IRCUT. The Dark filter is controlled internally by the app, you cannot control it yourself and it would serve no purpose to do that anyway. So you have two options, with LP filter or without it, which is called IRCUT state. There is no "no filter" condition, so when you use an external filter your only choice is to turn the LP filter off and you get your filter plus the IRCUT filter. If you were planning to do near IR imaging that will not work very well.