adjust time between slides with the custom slider

I am using the Sparky I would like to ask you if, for the “custom slider” (and not the “nivo” slider), one can change the number of seconds between the slides (I am using the sparky theme). At the moment, it is around 10 seconds and I would like to reduce it to 5. Still work in progress, my site is http://albertbanalestanol.com/

thank you very much

albert