Abstract: A method and apparatus for the colorimetric testing of non-opaque fluids that comprises compact test kit apparatus made from readily available plastic components, and sets of such test kits made even more compact by a combination of chemistries for certain tests that simplifies and improves the accuracy of those tests while reducing the number of test kits required in a set. The colorimeter component of each test kit provides non-opaque colored plastic windows made from readily available commercial materials that are accurately color controlled. The colorimeter also makes automatic correction of the color windows to compensate for any initial coloration in the fluid being tested. The colorimeter also serves as the container for one complete kit and allows a set of kits to hang from closely spaced hooks to conserve space and make them exceptionally convenient to use.

Abstract: An automatic device for closely held temperature control of a body of liquid via an electric heater, as for example via a liquid-immersed heater element. The control device provides an enclosed air space with shared exposure to ambient air and to air that has been heated by the liquid. Thermostatic-switch means and an electrical heater element are contained within the enclosed air space and cooperate to establish an on-off supply of electrical energy to the immersed heater element.

Abstract: An aquarium water-clarifying system is disclosed in which water at one location from near the tank bottom or gravel is raised through a first tube into a container to an accumulated level above water level in the tank; such raised water is transiently retained for water-surface air exposure in the container, and air-laden surface water from the container is then returned to the tank through a second return tube that also terminates near the tank bottom. The lower ends of both tubes are spaced from each other and give rise to a gentle circulation or sweep of primarily the stratum near the tank bottom, using only the air-laden surface water from the container. Under controlled conditions, in one embodiment, the return flow of such air-laden water may contain an intermittent stream of air bubbles.

Abstract: The invention contemplates an automatic device for closely held temperature control of a body of liquid via an electric heater, as for example via a liquid-immersed heater element. The control device provides an enclosed air space with shared exposure to ambient air and to air that has been heated by the liquid. Thermostatic-switch means and an electrical heater element are contained within the enclosed air space and cooperate to establish an on-off supply of electrical energy to the immersed heater element.