I did for years, then changed. so now it's not really a "flush" it's more like a "rinse". Keeping them "dry" just a cup or so as needed makes them grow fast. With my parameters anyway, regular nutes at full strength every other watering until day 45 or 50. Then, a one gallon drench of RO water (if available) for each pot, then dry until they almost wilt and another gallon drench, dry out cycle. After 2 cycles they are done. Buds are fat, they burn good with no residual ash and have the feel of Hashish as they are crumbled between sticky fingers. A person can develop their own way, for their own standards of joy. Whatever those growing and imbibing practices are that bring you the existential, bliss, relief, and peace of mind you desire. Peace signs...