Ok I have been using the open carts for a bit and I know the liquid darkens in light etc over 4 to 5 days. Thus is darkening the same day/overnight. I am using mediCal grade ejmix. The ratio is 1:1. 1 G of goodness to 1 ML of product. I am using the .3 ohm coil running at 15 watts now. I was running at 25ish yesterday and higher the first daym I add maybe .5ml of fluid to the tank at once since I keep many different flavors. I am using a melo 3 tank with a pico battery btw. If anyone has experience with this setup let me know. I want it to get me feeling right from car wrecks I was in but also to conserve which the disposable carts were helping with. Any advice is appreciated. Also I need to order more coils. Anyone else have any ideas on good coils for what I am doing. Low watt seems to work well for me and I'm using a .3ohm now.