Hi,
On a lot of the mini and junior hookahs you will often find that the part of the metal shaft going down into the water glass bowl is very short. Which causes you to raise the water level high  and their is very little air space.
I happen to have about 3 of these kinds of cheap  store bought lighters that some are refillable.
They are great for not burning hands when lighting coals, but I solved an even bigger group of issues.
Since they are cheap, when yours runs out of butane, you can refill it, but the flame will never be as long as it was before.
I had the idea of taking the black metal “nose” piece where the fire comes out of and easily detaching it. (In this picture above they are silver coloured which is even better.
There is a slight slit  an half inch long on the top of the pipe where it was added on by some underpaid Chinese worker to make a snug fit.
Well after detaching the “needle nose” part, I then fitted it perfectly to the smooth bore of the metal shaft which goes into the water!
The positive results are a few! One is a longer shaft, which gives you room to play with YOUR desired water level. You won’t have to blow smoke out of the top after every toke.
Secondly, look at the part of the “needle nose” where the fire comes out….You have there one nice sized bore, as well as from 8-10 tiny holes which act as the perfect diffusser. A diffusser makes many smaller bubbles, breaking up the bigger ones, making the smoke even cooler and filtering crap out of the water.
The sound when toking on the hose is more of a soothing hiss. If you don’t want to be caught smoking by mommy or daddy, don’t want to get caught by the dean in the dormitory at school, or don’t want to wake up your loved one, than this diffuser is a free trip for YOU.
I am happy as punch with the results!
Or as mentioned, take bending plastic straws and cut them down a third of the long part. In the big hookah shafts I got 5 in. In the smaller hookahs, 3 entered.
The also act as diffusers with the same results. Even better, each one goes in a different direction hitting the glass sides!
The “short straw” is that when you go to clean your hookah, you will find them midly dirty, which shows they filtered the water, and you must replace them with new ones.!
Hookah 1