Purge tower blob

I have an elegoo Neptune 4 plus, I'm working on a couple small multicolor prints, 3 colours, manual change. I've got it pretty well dialed in but after a colour change it purges this HUGE blob into the purge tower, which hardens and then the nozzle hits it and messes up the print. What setting do I have to change to get the damn thing to stop this?? I'd be perfectly happy with just a small purge line like it does at the start, especially since it flushes before resuming. Help!