We have an atmospheric pressure underground tank 8ft L X 14 inches W X 3 ft-4 inches deep ( 233 US gal capacity) .The bottom of this tank is 21 feet below the ground level. Water is seeping into this tank from surroundings at the rate of 0.3 gpm. It is a requirement that this tank should be continuously dewatered and preferably should be free from any water. The water is to be pumped into another adjoining atmospheric pressure tank 2 feet above the ground level by a flexible rubber hose.
I had thought of sump pump like Flygt SX 3(max head 34 feet) but this leaves about 4” level of water behind.
Could any pump guru suggest any suitable submersible, suction or other pumps for this application. Both electrically and air driven pumps could be used. Flow of pump is not important and could be say 5-10 gpm @ 27 feet. Width of tank could be changed to a maximum of say 20 inches. Pump shut off pressure should not be more than15 psig. The arrangement is required to work satisfactorily for about 4- 6 months.