“These were ALL that I used for ages, but now I've had to change to disposable because the quality of these has fallen off. They've added more air intake holes, but the batteries themselves don't last ...I mean, they charge and last during the day - but the unit itself quickly stops working. I used this version from V2 for many years, but these are not up to par. Also - they sent one that didn't work at ALL...and I had to haggle to get them to finally say, 'Well, we'll allow a ONE TIME replacement." ...Ummm - it CAME to me NOT working - I didn't do anything wrong?! Really weird situation. I'd love to know if they find a new manufacturer because I have LOADS of tanks and liquid left over.”