You cannot keep funds in your zerohas account because zerohash is regulated as a Dutch entity and under Dutch law zerohash is not able to keep funds in your zerohash account for more than 5 days unless those funds are "covered" by an open order. Consequently, funds in your zerohash account will be swept back to your brokerage account each day.
Trading, settlement and custody services in connection with crypto-assets through IBKR platforms are provided by zerohash europe B.V.