Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!usc!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!gryphon!richard From: richard@gryphon.COM (Richard Sexton) Newsgroups: news.groups Subject: .aquaria Message-ID: <20984@gryphon.COM> Date: 16 Oct 89 09:09:01 GMT Reply-To: richard@gryphon.COM (Richard Sexton) Organization: Trailing Edge Technology, Redondo Beach, CA Lines: 225 In article <1989Oct16.042758.456@agate.berkeley.edu> gsmith@garnet.berkeley.edu (Gene W. Smith) writes: > >Just compare talk.philosophy with sci.skeptic. It was >because I *knew* what sci.skeptic was going to be like that I >opposed it; it was (and is, and will remain) a "talk" group in >"sci". Funny. The world hasn't ended. People voted for it, passed it; they must want it there. Funny. The world hasn't ended. > Sci.aqauria will *never* be a real "sci" group. It's not a >matter of only a little science discussion--there is NONE. The >people calling for this don't seem to know the difference between >talking about technical features of their hobby, such as how to >kill snails, and a scientific discussion. You can't kill snails. Saying there is *NONE* is a little final, Gene. You could say there is little, or ``not much''. You'de be wrong there as well, but *NONE* ? Suck on this: # # There's been a lot of requests for "hard" data about O2 and CO2. Well, # here it is! My wife (a PhD in Biochemistry) and myself (a EE) have a few # tanks set up and have been doing some experiments with CO2 and O2. First, # some background. # # We have 4 tanks of interest. The largest is an 85 gallon, plexiglass tank # oriented towards plants. We have an UGF and 2 Aqua-clear 200's for filters # with a Magnum 330 for special occasions. Powerheads are used to run the # UGF. The tank is densely planted with wildly growing plants of all kinds # (which was our goal). There are 4 large anglefish, 8 large Rainbows, 15 # cardinals and a dozen assorted scavengers/algae-eaters. This tank uses # a Dupla CO2 injector. # # The next tank is a 55 gallon cichlid tank. It has an UGF with powerheads # and an Aqua-clear 200 outside filter. It has mostly plastic plants with # a large Anubia and a large sword of some kind (which are barely living). # There are 6 medium size Severums, 2 Festivums and a half dozen scavengers. # There is no CO2 injection. # # The third tank is a 29 gallon tank set up to breed angels. It has an UGF # with one powerhead and an Aqua-clear 200. There are a couple of Anubias, # some scraggly Amazon swords and an Aponogeton or two. There are currently # two large angelfish in it. No CO2 injection. # # The last tank is a 10 gallon tank set up as a control. It is bare except # for a powerhead, a large (6") airstone and a heater. # # Now, DATA! # # We have some LaMotte O2 and CO2 test kits which we use to measure the # dissolved gases. They are extremely well designed (and I assume, fairly # accurate). One word of note - we are at 5000 feet (Colorado) so the # O2 numbers may seem low. I show the percentage of saturation as a data # point. # # DESIRED LEVELS: # # This is difficult to determine (surprised, huh?). Using the tables in the # "Optimum Aquarium", it shows freshwater to be saturated with O2 when the # level is 8.1 mg/l at 25 degrees C. This varies quite a bit with temperature, # dropping about 1.5 mg/l per degree C increase in temperature. Using some # other reference, we determined that at our altitude (5000 ft), saturation # should occur at 6.8 mg/l. The _O_A_ also states that their 2500 gallon # tank will vary between 90% and 112% O2 saturation (more on this later). # So I guess this is the "desired" level. # # The desired level of CO2 varies with the amount of carbonate hardness in # the tank. The 2500 gallon tank has a KH of 10 degrees, requiring 28 mg/l # of CO2. We have about 4.5 degress KH, requiring about 15 mg/l CO2. # # CONTROL TANK: # # The control tank was filled with tap water and allowed to "settle" for 2 # days with just the heater and the powerhead running. The 10 gallon has # a pretty good surface to volume ratio and the powerhead was directed to # "ruffle" the surface. The temperature was kept at 77 degrees. # # When tested, the O2 measured 6.0 mg/l (also "parts per million"). This # corresponds to 88% saturation. The CO2 showed about 3 mg/l or Not Very # Much. Note that this tank has nothing living in it (at least nothing # visible) to use or generate CO2 or O2. Just plain water happily exchanging # gases at the surface. # # For fun we turned off the powerhead and turned on the airstone. This created # a "wall of bubbles" so should be representative of typical areation. After # running for a day, guess what happened. Nothing. No O2 increase, no CO2 # decrease (but, of course, there wasn't much CO2 to remove anyway). Draw # your own conclusions. # # 29 GALLON BREEDER TANK: # # We've measured the O2 once, at the end of a day. It measured 5.4 mg/l or # about 79% saturation. Our conclusion is that the fish use up the oxygen # and it can't be replenished fast enough through simple surface diffusion. # # 55 GALLON CICHLID TANK: # # We measured O2 and CO2 twice during a day, once just after the lights went # on (10:00 AM) and once at 4:00 PM. The intitial O2 reading was 5.0 mg/l # or about 73% saturation and the second reading was 4.8 mg/l or 70% # saturation. Obviously, the big cichlids are heavy breathers! BTW, they # don't appear stressed or oxygen starved and have good color. I suppose # fish get used to low oxygen levels just like humans (we lucky folks at # high altitudes have more red blood cells then you flat landers - nyah, nyah). # # The CO2 in the cichlid tank measured 5 mg/l at the first reading and 3 mg/l # at the second reading. I'm not sure why both O2 andf CO2 would drop during # the day. At these levels, the test kits have a poorer resolution and could # account for the differences. # # 85 GALLON PLANT TANK: # # OK, here's the interesting part. The 85 gallon has CO2 injection and very # healthy plants. We maintain the CO2 at about 20 mg/l (a bit high, but # we had no way of knowing). We have measured the CO2 at various times # during the day (11:00 AM, 4:00 PM and 8:00 PM) and found the levels # didn't vary more than 1 mg/l (20-22 mg/l). We were surprised because # we have a steady flow to the tank at all times and we thought when the # plants gave off CO2 at night, it would drive the level up. Apparently # the excess just diffuses into the air. # # The O2 was an entirely different story. In the morning, it measured 4.8 # mg/l or about 70% saturation, just like the cichlid tank. At 4:00 PM, # after 5 hours of light, it measured 7.2 mg/l or 105% saturation! Also # at this time, you can see little bubbles forming on the plant leaves and # the side of the tank. At 8:00 PM, the O2 measured 8.6 mg/l or 126% !! # We are careful not to light matches around the tank! Conclusion: those # healthy plants really do make O2, just like the book says! # # OTHER DATA: # # For reference, we use Dupla fertilizers in the plant tank. Duplagan, # DuplaPlant and Dupla KH Generator at water changes and DuplaPlant 24 # (daily drops) every day. We have 3 40w flourescent lamps, 2 Phillips # UltraLume (USA) and 1 Cool White, and run them 10 hours per day. We change # 25% of the water every 2 1/2 weeks. There is no algae that we can detect. # # One thing we found: if you use ultraviolet sterilyzers, you will remove # any iron from the water. We were adding enormous amounts of Dupla daily # drops each day and couldn't get the proper level of iron. Now we add 6 # drops per day and have 0.1 mg/l of iron as recommended. Currently, the # GH is 5.0 degrees, the KH is 4.5 - 5.0 degrees and the ph is 6.9. We # need to raise the ph to 7.0 by lowering the amount of CO2 being injected. # # We are not using a "reactor" for the CO2. The Dupla starter kit has a # "diffuser" that makes really teeny bubbles and seems to work just fine. # A five gallon tank of CO2 lasts 2-3 months and costs $8.50 to refill. # # Any questions? # # ---------------- # George and Karla # # ============================================================================== # DUPLA ANALYSIS # ============================================================================== # # We've had some of the Dupla products analyzed to determine what is in them # and we thought the Net might be interested. The analysis was done with # an Inductively-Coupled Plasma Emission Spectrometer. This machine will # vaporize a sample to reduce all components to the atomic level and then # determine the concentration of 21 different metals. # # Note that this analysis DOES NOT tell you how to make these products. There # is no way of knowing if the various metals are in the product as "trace # elements" or as contaminants. There is also no way of knowing, for # example, if all the iron is in a form useable by plants or if certain # elements are present because they bind other elements (sodium could be # used to chelate the iron, for example). # # Note also that the concentrations listed here are what is present in the # product and that it will be diluted A Whole Lot when it is added to the # tank. For example, DuplaPlant 24 (daily drops) has a concentration of # 11800 ppm of Fe. However, only 6 drops are added to an 85 gallon tank. # # PRODUCT USE: # # Duplagan and DuplaPlant tablets are added at each water change. Among # other things, they are supposed to add "bulk" trace elements, that is, # trace elements that can be added in a large enough concentration to last # for 2 weeks (or whatever) and not be toxic to the plants or fish. The # DuplaPlant 24 (daily drops) contains trace elements that must be added # in small doses due to toxic effects. # # ANALYSIS (all concentrations in parts per million): # # Dupalgan DuplaPlant DuplaPlant 24 # Metal water cond. tablets daily drops # ------------------------------------------------------------------ # # Ca calcium 30.5 55.0 14.6 # Mg magnesium 509.0 2.9 0.5 # Na sodium 54.0 1160.0 4840.0 # K potassium 9.6 24900.0 <0.5 # P phosporous 0.8 2.5 6.5 # Al aluminum 0.5 3.5 4.8 # Fe iron 0.3 2340.0 11800.0 # Mn manganese 0.02 368.0 12.5 # Ti titanium 0.1 5.9 0.2 # Cu copper 0.05 1.8 1.3 # Zn zinc 0.3 5.7 1.1 # Mo molybdenum 0.05 6.7 0.9 # Cd cadmium 0.01 0.2 0.7 # Si silicon 2.07 57.0 8.2 # Cr chromium 0.07 0.9 1.8 # Sr strontium 0.3 0.3 0.04 # B boron 0.03 66.7 20.2 # Ba barium 0.08 0.05 <0.01 # Pb lead 0.26 1.3 4.72 # V vanadium 0.07 0.6 2.06 # # ------------------ # George and Karla -- Help wipe out BBQ lighter fluid in your lifetime richard@gryphon.COM decwrl!gryphon!richard gryphon!richard@elroy.jpl.NASA.GOV