I have a homemade flood drain table that is made out of a 3x3 planter with two one inch holes drilled into it.With 3/4x1/2 inch reducers syliconed into place one to flood the table and one to drain. the drain is hooked up to another 3/4x1/2 reducer at the bottom of a 10 gallon resivor and the other to a 170 gph submersible water pump both with 1/2 inch tubing.whin I fill my resivor up and plug in my pump the planter completely fills to the top and overflows what should I do about this I thought about adding another drain hole but I dont know?