This is an advertisement from the Aquarist for Springfield heaters/thermostats for aquaria:
I also came across a report in Water Life of a talk given by Charles Schiller in 1936:
The Chairman then asked Mr. Charles Schiller to give his lecture on the " Lighting and Filtration of Aquariums." Mr. Schiller dealt first with filtration, explaining that filtration does two things: (1) it removes solids from the water and (2) by passing the water through carbon it removes gases, the efficiency of this latter process depends on the quality of the carbon and the time the water is in contact with it. Mr. Schiller then went on to deal with the ordinary air-lift filter, and also the "Schiller" system, which is a German patent*. He also described a method of using three large jars connected to each other which, with the aid of a powerful pump, will filter the water in a twelve-gallon tank in ten minutes. At this point Mr. Schiller gave an interesting description of the making of the aquarium for the Queen Mary and the difficulties experienced and how they were overcome.
Dealing with the lighting of aquariums, interesting points which Mr. Schiller mentioned were, that when plants are lighted they also require heat for satisfactory growth, that minute quantities of salts, such as 1 /1,000th part, make a great deal of difference to the growth of plants, and that the nearer the light is to the water the better it is. He also mentioned that a 60-watt strip lamp is required to light two cubic feet of water.
Some interesting data given as to the effect of light on plants were as follows:—Tank illuminated six hours per day—plants died and rotted. Tank illuminated eight to nine hours per day—growth good. Over and above this amount of light the plants become lanky It was also mentioned that sixteen hours' use of a 30-watt lamp will not equal eight hours' use of a 60-watt lamp.
At the end of his lecture Mr. Schiller answered a very large number of questions. He was then thanked for the trouble and care he had taken to give the club such a very interesting lecture, and the meeting concluded amid applause.
*I have searched for this patent but have failed to find it.
Finally, in this series, the cover of the Golden Jubilee edition: