Use a soaker hose and attach it to an air compressor with fittings from home depot. You may have to use some landscaping rock to hold down the hose since the hose will float because of the air going through. It is noisy but effective.
I use my former home sump pump(I replace the home pump every 4-5 years) to circulate the chemicals when my filter is shut down. Occasionally during the summer when I need to slam; I use to same pump. Just run the pump withoutany pvc attached