Actually, the pulsating is 'normal'. That's not to say it isn't somewhat irritating. But the fact that it pulsates means that your filter is allowing sufficient water to pass through.
This is assuming that the pulsating stops when the faucet(s) are turned off.
The pulse is the pump kicking on to pressurize the system (which, on our little Tugs is a pretty small system). Then, once it hits its predetermined pressure, the pressure switch is triggered and the pump kicks off. The pump has a higher flow than a single faucet - which has numerous flow restrictors - can let by, so the pump very quickly reaches its pressure setting, which turns it off. If the faucet still on, the pump has to turn back on to keep the flow going. This happens a couple times per second, thus our "pulse".
If your filter was plugged, the pump would not get sufficient water to pressurize the system, and would constantly stay on, with little to no water flowing through the faucet.
I believe others have found pumps that are more suited to our system, and there are other threads about this. I, however, think I will first try installing an expansion tank (if I can find a small one - 1/2 gallon or so) in the system so the pulse will be minimized. The expansion tank will allow the pump a larger place in which to "store" the extra pressure, thus the pump cycle will be much slower.
