Didn't we say to not try SPS until nitrates were below 20 ppm? Seriously, have patience and solve the water chemistry before burning more of your money. I advised you on one large water change as small ones will not be as efficient. I laid out the math in your other thread.
Here is another example:
Original 60 ppm nitrate (assuming 200G volume):
One 75% water change (150G) = 15 ppm
Two 50% water changes (2x100G) = 15 ppm
Five 25% water changes (5x50G) = 14 ppm
Ten 12.5% water changes (10x25G) = 15 ppm (this is the method you are following.....expect many more water changes to get to "acceptable" nitrates for SPS)
Here is another example:
Original 60 ppm nitrate (assuming 200G volume):
One 75% water change (150G) = 15 ppm
Two 50% water changes (2x100G) = 15 ppm
Five 25% water changes (5x50G) = 14 ppm
Ten 12.5% water changes (10x25G) = 15 ppm (this is the method you are following.....expect many more water changes to get to "acceptable" nitrates for SPS)