would i jsut clean out the whole pot and jsut use pure water? -

Im not sure what your thinking here.. but ok Im guessing you have like the waterfarm with hydroton pellets and the air pump that bubbles up water to drip out of a ring right?? so you just dump the water out of the bottom part.. use RO water (i will say that again) Use RO water to fill the system back up by pouring it into the setup thru the hydroton the plant is in and run the bubbler steady for an hour or two (this is the part where you could be using FloraKleen or any other flushing product - I reccomend florakleen).

If you like it cheap and easy you can refill the system with bloom nutes now.

Optional-

Once this is done if I have time I go ahead and repeat using only pure water until I get a very low TDS rise on the flush and I use my TDS meter to verify when the flushing water no longer has rising ppms and then I know the flush is complete. At that time you can refill the system

Flower at about 1ft sounds good to me.