Laminar bounce

I am sure this has been covered here but have not found an answer to my exact problem. My stream is great and flows about 8 ft long and 4 feet high but it slowly rises and falls around a foot. It will run for 30 seconds or so at 4 feet high then slowly decrease to 3 or 3 1/2 feet high then slowly climb back to 4 feet. It does this as long as it runs. My bypass filter is 4 inches in diameter and 28 inches tall. The inlet is 3/4 as is the outlet. The outlet is six inches above the inlet and I was wondering if thats too close. If not any suggestions on getting the stream to stay at one height?

I've had that problem before too!! Mine would shoot just fine as soon at it would reach the maximum arc it would fall (quickly) to a much small arc then slowly build up to the max again and repeat itself.

My setup was

I had a large bucket where the water would land and get pumped out to the filter and then to the nozzle which was 10 feet (3m) away.

Here is what I observed.

The pump was getting disturbed by the water landing near it. When the water would hit near the pump the inlet pressure was screwed up and so at that instant it didn't pump the required amount to keep the filter completely full! So that eventually was transfered to the nozzle and the stream would fall.
While in the fallen state the pump was not getting disturbed by the stream so the pump could pump the required amount to fill the filter again. Once the arc got high enough to reach the maximum it would hit the pump (or around the pump inlet) and mess it up and start all over again.

If your stream water is landing near your pump, try rearranging your pump so that it isn't so close to it.

THanks but thats what confusses me. I am currently just running the nozzle in a test state and am running it straight off a water hose fed from a tap. It is feeding directly to the bypass and I am shooting it into a sink.

Sounds like the jitter filter is full of water. Do you have any way to check that whiles its running

That is so strange! I was sure that you were having the same problem I was having. Maybe it still is the same problem.

I'm pretty sure that the problem lies within your filter. Are you running the system off of the hose from the house? House pressure is pretty constant (for the most part), have you ever tried running the nozzle straight off of the hose? I would suggest removing the filter from the system and running the nozzle straight from the hose. This way we can see if the filter really is the problem.

Yes, try to remove the low-pass filter and see if the problem still is there !

Seems like a strange problem, can there be some air problem inside the nozzle ?

I have removed the bypass filter and connected straight to the nozzle and the problem still exists. I believe that there I am getting the rise and fall from the water pressure changing. I think the filter and nozzle are ok and that my water pressure is not constant.

If there is no change then it sounds like your jitter filter has no air in it when in use.

Can you time how long it takes to go from max arc to min arc? Or just give me an estimate

less than 1 second
1-10 seconds
10 - 30 seconds
30-60 seconds
more than 60 seconds.

The time from max to min is about 15 seconds. I have discovered that our pressure varies here. I disconnected the hose and began using a small pump (just to test) from a container and running the water through the bypass again and the fluctuations dissappeared. Thanks for all the suggestions

Glad to hear it!