blowing sand, and more QUESTIONS!

I have (1) 500 GPH PH in my 29gL tank. It is re-arranging my sand and everytime I relocate the pump it moves sand in an other location. I know many ppl dont like/have sand but I do like the look of it and would like to have it though, I may have to reduce the amount. I can't imagin getting another PH as I have seen most reef tank have 2 and it was suggested i have 2 when I get coral. So I was going to place it at the bottom blowing upward but I dont think thats how it should be?

Any thoughts, suggestion or otherwise? eric3316 you run 2? in a similiar size tank correct? I know you dont have sand now but did you?

My sand is now covering a very pretty, purple, expensive rock! I will be disconnecting my filter once the tank clear from me fooling with the sand but I dont believe the water flow from the filter could be contribuiting that much movement to move my sand.

Also, when I move the sand the water clouds up for a short while. Should I vaccume the sand? Or will I take away good stuff? I dont think I want to get rid of the sand totally...And if I need more circulation with coral and I get a 2nd pump it will be like a TORNADO in there! Is it all trial and error in finding the right place in the tank? or is there a correct formula on how to place 1 or 2 pumps?