David Pagan Butler, inventor of the Organic pools bubble flow circulation system, shows how different diameter pipes work as air-lift pumps.\r<br>Free pdf: \r<br>And have a look at the great variety of DIY Organic pools David has inspired: \r<br>You can buy Davids classic DIY film Make a Natural Swimming Pool:\r<br>vimeo.com/ondemand/organicpools
