[Canadian]

I think the most labor intensive part is that you can't readily miss a few days while you go away for the weekend for example. Most fish will be fine without food for a couple days. And if I needed to be away for longer than a couple days I could quite easily have someone feed my fish specific quantities of food. However I would be worried (unless I had another ULNS hobbyist sitting for my tank) that someone could easily mis-dose my tank.

I've long wanted to try the Fauna range of products for ULNS but my experience with VSV in the past coupled with my frequent travel schedule always left me concerned while I was away with someone else dosing my tank. I could very well automate things with an additional dosing system but a) I'd still be worried about malfunctioning of the dosing system and b) the cost of the dosing system would leave me having to wonder if it was justified in comparison to the results attained without it.

The great results obtained with several of the ULNS are very appealing. And I agree that as they become more mainstream with better customer service/support --> improved understanding and knowledge there will continue to be transition towards their use. The uncertainty about things like potassium dosing and the lack of any quality test kits to obtain valid and reliable results does make me a little leary about dosing those things in my tank however. Hopefully continued use of ULNS will contribute to greater understanding about a lot of the essential components and weed out some of the unnecessary ones.