Size of Low Pass Filter???

I'm hooking up two nozzles to my return line from my pool pump shooting the streams back into my pool. So far the project is going well except that I'm trying to get the pump jitter out. I made two low pass filters and hooked them up in series but I still have a good bit of movement in the streams. I was wondering how much diameter and length mattered with the filter?? I would think that the taller the better as it provides a larger air chamber to absorb pressure changes. I'm using 6" pipe and they are both 5ft tall with the bottom 18 inches as the water chamber. I'm also throtting the individual streams for both nozzles after the low pass filter where the lines split to keep the streams the same size. Has anyone tried to see the difference between throttling the flow before and after the low pass filter to see it it helped out?? I'm thinking about adding a valve before the low pass filter and throttling from there is it'll take more jitter out.

Thanks for any help!!

I think we should pay more attention to the lines/flexible tubes? we are using, because they introduce a large pressure drop. Small changes in the shape of the lines, like a little bending, will introduce variations in the pressure drop. Therefore, I would suggest to make the line between the nozzle and the low pass filter as short as possible. In your case of two nozzles and filters: each filter as close as possible to each nozzle. I hope I can do some experiments this summer.