MiracleGro urea residue removal?

[Joebase]

I use large quantities of Miracle Gro fertilizing large pots of annual flowers. Anyone know a way to dissolve the white residue that builds up on stone or tile after repeated applications (I assume this is the insoluble urea in the product.). I usually wash down these surfaces after the stuff has drained out but cannot do this all the time, thus the problem. I have been fairly successful with Muriatic but the neutralization tends to be messy and leaving it too long has overetched some of the surfaces I have treated. Any ideas out there?

 

[jedishrfu]

On Answers.com someone suggests using 25% bleach solution with kitty litter pickup:

http://www.answers.com/Q/How_do_you_get_miracle_gro_stain_out_of_concrete

 

[Borek]

I doubt the residue is just urea, as if it were it would be quite easy to remove just with water.