I have ordered from you the 510 and am wondering a few questions. Do the carts have to be topped off as much as a 901? Those 901 carts are so dinky they have to be constantly topped. I also saw a review from igetcha on the Titan which is the same, correct? I understand there were problems with some of the units coming out of China but the new ones have been fixed and the problems resolved. I want to make sure you have the new ones that dont have issues. I am very excited since I have heard great things about the 510 as well as your comapny. Thanks for any info