For an annual cost of $250, FERTIGATION SYSTEMS will professionally maintain and fill the injector. This system is proven and automatic, but the greatest problem with them can be that the homeowner doesn't fill them on a regular basis. Since here in south west most of our yards are desert landscape, we will only need to fill the injectors every three months. We buy professional grade fertilizer in large quantities and mix them ourselves - changing the mixture for the different seasons. This is a stronger product than available at retail, and your landscape greens up faster and stays green longer. Nitrogen, iron, potash, phosphates, and other micro-nutrients are added - but never any herbicide or insecticide, since these injectors are attached to drip/sprinkler systems directly. FERTIGATION SYSTEMS will guarantee that fertilizer is in your injector every quarter. We have a supply of parts for the different injectors on the market, or can procure parts needed for repairs.