Florakleen on rockwool ?!?!?

Can florakleen be used on rockwool to flush out salt build up? I guess nutes have been building up in my hugo blocks and run off is in the 2000-3000's I washed them out once with plain water then fed after plain water again then noticed some N def on older leaves so I fed again now I am seeing browning tips on my flowers and flower growth has slowed a lot. I am thinking I need to unbind off the nutes in that rockwool to get a clean slate and get my flowers back to normal for the last mile of the race.



Kind of hard to see but if you look closely the tips of the flowers are starting to yellow and get discolored. I believe it is excess nutes in the rockwool burning them

Well I went ahead and used it anyway, and the runoff was somewhat surprising.

Here is the plant I am flushing

here is the runoff from the cubes



I am not surprised the flowers and leaves were acting weird after seeing how much crap was in the runoff water.

Oh my lord I was scared to stick my TDS meter in it and I did and it read 5000