52 C. M. BREDER, JR. 



involved in maintaining a similar number ADDENDUM 



of standing fresh-water aquariums. After g.^^^ ^j^.^ ^^^.^.^^^ ^^.^^^ ^^^^^ published the 



the equipment is built and regulated, so ^^^^^^^, ,,|aitional data have been ob- 



that valves and controls are m balance, . , 

 there is nothing to be done with them at 



any time, and in fact there should be no Control of inflow 



tampering with them at all. It is prob- Since stopcocks with Teflon, or similar, 

 ably wise to post warnings to this effect, plugs have become available, it is possible 

 There is little aquarium cleaning to be to simplify greatly the construction of 

 done, as most of the accumulating detritus small float valves. As these newer type 

 is automatically deposited in the filters. stopcocks are usually provided with rather 

 Aside from feeding the fishes and some- heavy glass tubes, no special support is 

 times cleaning algae off the glass sides, needed, the glass tube being quite strong 

 the latter being controlled by adjusting enough to support the float with the tube 

 the lighting arrangements, there are the fastened rigidly only at the inlet side, 

 following routine matters to be done. The only modification necessary is the 

 These will vary with each installation but removal of the usually colored handle in 

 may be approximated by the regimen the Teflon plug. This is easily forced out 

 under which the described installation of of the hole in which it rests. It is re- 

 seven aquariums were controlled, as placed by a suitably sized rod, such as that 

 follows: ghown in text figures 2 and 3. This rod 



Minutes carries the float assembly and connects it 



Read pH and specific Twice a week 5 with the valve plug. As these valve plugs 



gravity. are held in place by a Teflon nut, there is 



Titrate sample Once a week or less_ 15 ^^ ^^^^^^ f^^, modification or construction 



Fill distilled-water car- Twice a week .5 « t tt e ^ ^i . i 



of a holding frame such as that shown m 



boy. =■ 



Clean filters Once in 2 weeks— 15 text figure 2. Incidentally, these plugs 



Make the adjustments Once a month or are not liable to stick, even after several 



based on above in- longer Var- years of ser.vice. 



formation. ious 



rr^, 1 j; 1 • J.U „j Constant-level siphon 



The need for changing the pump and "^ 



motor is such a rare occurrence as not to The constant-level siphon illustrated in 



figure in the above schedule and should text figures 1 and 3 can be made virtually 



not take more than 5 minutes. Every at- foolproof if the open end of the glass tee, 



tempt has been made to reduce the mainte- ^^l^i^^ faces upward, is extended by a piece 



nance of the system to its minimum. It is of flexible tubing. This piece should be 



not uncommon for the system to be left bent over so as to form an inverted U, 



alone for as long as 3 days, as over a long with its open end facing down, into the 



weekend. The only thing to normally ex- aquarium. This is most easily accom- 



pect at the end of this period is some plished by providing a third hole in the 



extra-hungry fishes. It should be borne supporting crosspiece. The open end 



in mind that the smaller the system— that should be placed slightly above the level 



is, its total amount of water— the more of the outflowing water in the horizontal 



rapidly decomposition or contamination arm of the tee. 



can spread through it. It is prudent not A siphon so arranged will prevent over- 



to reduce the size of the equipment more flowing of the aquarium even if the in- 



th an necessary. coming water is increased over a consid- 



