This weekend we has an aerator installed to help get rid of the
sulpher smell in our water. It's just a small brass thing that lets
some air in the lines to oxidize the sulphur. It works great - no
more smell.

It worked great for about 2 days. However, there is now air in our
lines which makes all the faucets and the toilet very noisy and
"sputtering." Also, since the water is not flowing at a consistent
rate through our on-demand water heater, we do not get consistent hot
water - it seems to turn on and off as the water and air runs through.

I see that there's a nut on the side of the aerator, I assume to
adjust the amount of air in the lines? I'm waiting to hear back from
the plumbers who installed it, but was hoping maybe someone would know
if this is all I need to do? I was thinking of shutting it off all
the way, then running the water until there's no more noise, then
slowly opening it back up. How long should I wait between
adjustments? A few minutes? Hours? Days?