[macabethiel]

Originally Posted by Lazy-Ferret

Most fish tank don't spark, they use a pair of electrical coils, to pull a solenoid connected to a pair of bellows back and forward. Main problem is, the bellows tend to work harden, and you have to replace them every year or so.

What you ideally want is one of the old Medcalf Hy-Flo pumps, beautiful bit of kit, they use a coil to induce an eddy current into an aluminium disk, that then revolves, and drives 2 crank shafts connected to little pistons.... all you have to do is put a drip of oil on them once a month or so. Only problem is, they fetch quite good money now, as they are collectors items. I had 2 for my fish tanks, spent almost as much time watching the pumps, as watching the fish... Other thing is, rather than the annoying buzzing the modern ones make, these do a relaxing chuff...

I had one of the last Hy-Flo Pumps before they stopped production it was a double piston model it was mostly brass with a black plastic / ceramic cylinders. It was a work of art in itself watching the flywheel run. Sold it on e-bay about 10 years ago for more than it cost.