Im using a vamo v2 @ 5.5w with 1.8 heads with a almost new pro tank. Ive gone through many tanks with no issues, never got that metallic tast peoe talk about. But now alot of the time its tasting funky! Ive tried new heads as i have many of them. Rinsed with hot water, Lower wattage. Just cant seem to figure it out. I just refilled it and the first 3 or so vapes tasted normal after that straight funk! Im vaping bb and gj if that helps in any way. Thanx guys!