Knots for adjustment of height?

So i have a couple of ghetto Cfl lamps set-up with some mylar reflectors for a couple of mother plants, atm they are just hanging by simple loop knots of twine and are a pain in the rear to adjust.

So do any of you former boy scouts out there know of a good knot that will allow me to adjust the height of my lamps without having to undo and tie up again?

Just the name would be ok then i could google it.

Basically a height adjusting knot?

Big thanks for any help.

How about tying in little loops every inch or so and then using a hook of some kind. I use a chain and the links that way. Or, a good strong calmp will do it but be careful with that, falling lights do a lot of damage.

When I was running CFLs they were suspended from the roof using a simple screw hook, the rope went from the bulbs, through the hook, and then down to a piece of r=wood near the floor that the string was attached to and by spinning the wood it either twisted up or untwisted the string thus raising it or lowering it. Was pretty simple to work with

Cheers for the advice fellas, its all good. But i think im just going to use some chain and hooks and be done with it

A prusik knot might be your best bet.

Chain is better if you have it.