Huge problem with ibanez rg2570 prestige

hey, i'm not really sure this is the right place for this topic but im preety desparate.
I own an ibanez rg2570 prestige, and it has those float bridge things that supposed to keep the guitar from going out of tune, and you should only open them when you want to really change the tuning.
so, I wanted to tune it down a half step(Eb), released the screwed and tried to tune it down, after a few failed attempts I noticed that no matter which tune head thingie i turn, it will largley affect the string it is attached to, but also will slightly change the tune of the rest of the strings, making it allmost IMPOSSIBLE to tune it!

Am I doing something wrong? is it a problem with the guitar? please help!

You're not doing anything wrong, it's just really difficult to detune a guitar with a floating bridge, i had the same problem with my ibanez Rg350. You'll need to keep adjusting the springs and the tuning for each string and when you're close to having it in tune; use the fine tuners on the bridge. Or do as i did and buy a guitar with a fixed bridge instead :rolleyes:

I have a Prestige and a Jem, I always make a balls out of changing strings so I usually wait untill I'm booking studio time then I get a tech in one of the guitar shops to give it an overhall (new strings, tuning, intonation, action, truss rod adjustment etc). Costs 20 euros here, can't imagine it would be more in the States...