For filtering, 2-Blacks & 2-PF-2's (4 filters) this can not be beat.Be sure to order the Stainless Works SSS012 spigot replacement.The unit, if permanent, i.e., in a kitchen, is weak in one point.. it needs manual refilling.This was not acceptable, and the glass water-level spigot is not only expensive but does nothing to solve the fill-it-by-hand inconvenience.Overcome this glaring problem by modifying the unit to Refill Automatically.[Any Warranties by any MFG involved will obviously be VOIDED]... but this Mod works!Here is the very basic method we used to accomplish a finished working Berkey Auto-Fill unit.1- Locate a Adjustable Mini Float Valve For Aquarium RO DI Reverse Osmosis System on Amazon or eBAY etc, and enlarge the Berkey lid hole for the float threads to poke from the inside to the outside. The float will be hanging in place, attached to the lid. The lid center-hole is drilled larger to fit this top float-valve, with the valve water inlet protruding through the top of the lid, and the float hanging under the lid. (effectively the float hangs downward into the Berkey's top can. To drill the center-hole larger, cover the Lid with seran wrap or such, on both sides, to protect the finish... (any twist or abrasion may, will, mar the 'mirror' finish of the chrome look). 'Sandwich' the lid with 1/2'-inch or so wood blocks top and bottom, (having pre-drilled a pilot hole, the size of the lid-hole, and line up the wood with the existing lid hole...C-clamp wood in place with reasonable torque. After lining up the lid's hole and two clamping blocks, use standard metal drills, (three sizes and oil, up to finished dimension to fit the valve hole needed to install the float-vale).2- Drill a screw hole to thread, on each side of the lid, for a small screw, size-6?.A screw goes on each side of the lid. The lid hole is large enough for the two screws to easily fit through.The two receiver holes in the side-wall of the Berkey must be drilled with a proper 'tap-drill' size to fit the 'fine-thread' of the 2 chosen screws.These two screws will prevent the lid from 'lifting' when the water in the top chamber lifts the float ball high enough to shut off the incoming water flow/pressure. The float should stop the water about 1.5 inches from the top lip of the upper tank.(A float-valve will general handle 60 p.s.i., but we had pre-regulated our pressure down to 40 p.s.i for a prior filter system, so we left that control in place for this Berkey DYI project). Remember, the Berkey cans are a thin metal, treat the 'threads' with a light-hand so as not to 'strip' them out. You are NOT tightening the screws, you are ONLY 'holding-down' the lid, pinning-it, so it cannot rise against the pressure of the float.Do NOT seal (air-tight) the lid to the top can. Do NOT seal the bottom can to the top can. Just let them all sit, together, as designed.3- Coming off the top of the LID, (with a copper 'Ell' adapter), the float-valve is fitted from the inlet to a 1/4 compression soft-copper pipe, connected via a 'compression-Tee' to either the Sink or Refrig. water supply inlet.With the float in place, the LID screwed on, and copper tubing connected (but not as yet turned on), this completes the Top Tank portion.Auto-FILL is no longer a problem.4- Now the Bottom Tank has to be fixed, to have the incoming filtered water stopped, before it overflows.To achieve auto-SHUT-OFF, a second float is needed to be installed, inside the LOWER Berkey tank.Do not use a second Mini Float Valve for the bottom tank, as the mini-float is too small a float to properly work in the lower tank.Instead find a new plastic (or) copper float-valve unit that is designed to control the water level of a Evaporative / Swamp Cooler's water pan.This would be found as a 1/4-Inch Compression Evaporative Swamp Cooler float valve.This Cooler "float" is large, but not overly large as the float will be fit Vertically in the center of the lower tank, even if the Berkey has 4 filters installed. This larger size of float is "needed" to properly cut-off the water flow to the bottom tank as it fills.(The float bobs VERTICAL in the center of the tank, but the valve itself wants to be close to the tank's bottom, thus the hoses support the valve down near the spigot)5- One short piece of medical-grade (clean) rubber (or) plastic tubing, exits out the bottom of each of the two PF-2 filters, and the other end of each of these tubes joins into a plastic (or) metal 'Tee' making a completed loop, water dripping from each PF-2 filter, out and down their rubber tubing into a Tee, and continuing down into the bottom float-valve.The lower PF-2 filter's (water exit holes), are not threaded. (You may attempt to carefully thread the PF-2's for a hose/adapter attachment if you have the proper tap and hose adapters but contamination may result without careful forethought). The method we used, considering only 'gravity feed' pressure is exerted on the filters into the lower tank, is to sli...