I usually avoid decorative water features, but I had to replace the pump in an urn bubbler for an existing customer. I installed a 500 gph mag drive which, as best that I could determine, is the standard size for this type of water feature. The customer would like the water to have a greater height than the approx 2 -3 " that it presently has. My question is: Instead of moving up to the next larger size pump (700 gph). could I instead place a cap on the existing 1/2" stand pipe and drill a smaller than 1/2" hole to increase the PSI? How much smaller hole would I need to drill to get about 6" in water height?