Hey john,
Its not that your post is too retarded to be answered, but I have also noticed it takes a considerable amount of time to get questions answered sometimes.

QUESTION:
Im using rockwool in clay rocks, suspended over my reservoir, my questions are: How far below the rockwool do I have my nurtient soloution?
ANSWER: You want your nutrient solution to be at the bottom level of your rockwool until the roots have actually grown out of it... Rockwool holds a lot of moisture, so you have to watch out for the potential problems...

QUESTION:
Mines not self draining.... so how often should I completely flush/change/clear out the nutrient soloution?
ANSWER:Self draining meaning Ebb and Flow? You should completely Rechange your nutrients every 2 weeks or so, But you will probably top off your reservoir everyday.

QUESTION:
Oh lastly, what would be the best way to cleanse my rockrool of PH before I use it.
ANSWER:
You are to soak your rockwool cubes/blocks in water with a PH of 5.5 for a minimum of 24 Hours... This should correct any PH problems...

I actually had to do some guesswork- PH pen wasn't working and i had to add an unknown amount of PH down to water to try to get it as close to 5.5 in my head...



Anyway hope that helps