need to get rid of 3-4 mantis, they are destoying my rock!rock dust everyday.not to mention all the empty shells from what they have eaten.going to start with air nozzle then seltzer/club soda then, oh! I hate to say it "the dip".Any Experiences,trials,advice,ideas would be helpful. I have read to many conflicting stories on fresh water dip.all dies non dies?