Submisible pump ** is self-prime as long as the water level complies with its requirement. Usually, must be above it. While external pump may or may not be self-prime. Some ** requires water must be already in the piping system for it to work While others will prime itself thus, drawing water from the source and pump to whatever destination. ** You have to be careful of these 2 types of pumps especially more so for submisible pumps. If the water runs dry while the pump is still running, the pump will overheat and may cause fire or a nasty shock if you put your hand in the water or touch the pump. Always read the specs as most of these pumps use AC. As for the external self-prime pump, running dry usually not a problem as it is designed to run as such. The down side is, this type of pumps usually cost much more (can be as much as 3 - 5 times more) than the other 2 types. John Waters wrote: Hi All, I want to pump water from a tank to a container using a small pond submersible pump (or whatever pump), but when the pump starts, there may not be water in the pipe that goes from the tank to the container, as a result a continuous flow won't start, I don't want to give the trouble for the user to fill up the pipe everytime when using the system, is there any method to start a flow from a dry pump? I can add any electronic circuit if needed. Thanks in advance! John _________________________________________________________________ STOP MORE SPAM with the MSN Premium and get 2 months FREE* http://join.msn.com/?pgmarket=en-ca&page=byoa/prem&xAPID=1994&DI=1034&SU=http://hotmail.com/enca&HL=Market_MSNIS_Taglines -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. --------------------------------- Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.