ajmckay Posted July 28, 2009 Share Posted July 28, 2009 Seabass, I'm impressed with the overall progress of this experiment. Last week I was wondering about it, but due to my crappy search skills I wasn't able to find it until it popped up on the main page! Anyways, I can't say that I'm very surprised by the results. My thought has always been that the bacteria grow in an exponential fashion. I believe that by doing water changes we don't remove much bacteria at all, but rather we remove the ammonia. But by doing this it keeps the sustainable level of bacteria relatively low compared to leaving the ammonia in and letting the bacteria grow. In other words both buckets are producing ammonia at the same rate, but the control bucket processes it faster (thus explaining the higher nitrite and nitrate levels). The test bucket is being given the fish rather than learning how to catch fish. It would be interesting to devise an experiment to measure the processing capacity of bacteria during different stages of the nitrogen cycle. Anyways, enough of my rambling... I'm excited I found this thread again. Keep up the good work. Link to comment
seabass Posted July 29, 2009 Author Share Posted July 29, 2009 Seabass, I'm impressed with the overall progress of this experiment. Thanks, and welcome back to the thread! I'll be glad when I can take a break from testing again. I believe that by doing water changes we don't remove much bacteria at all, but rather we remove the ammonia. But by doing this it keeps the sustainable level of bacteria relatively low compared to leaving the ammonia in and letting the bacteria grow. In other words both buckets are producing ammonia at the same rate, but the control bucket processes it faster (thus explaining the higher nitrite and nitrate levels). I basically get what your saying (exporting ammonia compromises the test container's ability to process it at the same level as the control container). However, since NH 4 + in the test container has remained as high or higher than the control container, it appears that the system's ability to process ammonia has been compromised by something other than a lack of ammonia in the water. On a side note: it's interesting that even though ammonia is near zero in the control container, there's still a lot of food on the sand bed. Link to comment
seabass Posted July 29, 2009 Author Share Posted July 29, 2009 Day 22 (final week): Test and control containers Closeup of control container (before the addition of daily pellets) API ammonia test Seachem ammonia, nitrite, and nitrate tests Closeup of the Seachem ammonia tests Link to comment
seabass Posted July 30, 2009 Author Share Posted July 30, 2009 Day 23: The ammonia level finally appears to be dropping in the test container. In addition to normal testing, I did pH tests on both buckets and performed the 11th partial water change on the test container today. Ammonia (NH4+), test container: 0.25 mg/L Ammonia (NH4+), control container: 0.15 mg/L Nitrite (NO2-), test container: 1 mg/L Nitrite (NO2-), control container: 1 mg/L Nitrate (NO3-), test container: 2 mg/L Nitrate (NO3-), control container: 5 mg/L pH, test container: 8.1 pH, control container: 8.1 Link to comment
seabass Posted July 31, 2009 Author Share Posted July 31, 2009 Day 24 Test Results: Ammonia (NH4+), test container: 0.15 mg/L Ammonia (NH4+), control container: 0.05 mg/L Nitrite (NO2-), test container: 0.5 mg/L Nitrite (NO2-), control container: 0.5 mg/L Nitrate (NO3-), test container: 1 mg/L Nitrate (NO3-), control container: 5 mg/L Speculation: First of all, I agree with Mr. Fosi's point that more data is required to properly interpret the results. However, I'm intrigued by the outcome so far and have a few thoughts about it. 1) You can see that the food particles are more dispersed in the test container (on the left): Is this break up due to a misaligned powerhead nozzle, disturbance during water changes, or from breakdown caused by bacteria? In addition, might this breakup of food particles increase the process of ammonification in the test container? It had been previously suggested that grinding the food and using premeasured amounts might solve this potential variable. 2) When typing up a reply to the following post from HydorMan and recalling similar posts from other members, I started thinking about limiting factors again: The thing to remember is that the conversion of Ammonia to Nitrate is dictated by the number of bacteria in the system. This result suggests that the number of bacteria in the water column is critical to the ammonia reduction rate. Water changes remove these free floating organisms. While I feel that this may play a small role, it is commonly believed that the majority of the bacteria live on hard surfaces and not in the water column (thus limiting, but not eliminating this effect). Another possibility is that in order for the the bacteria to ramp up to maximum reduction rates, there has to be a critical level of ammonia in the system. If this level is never reached the population of bacteria never grows and works at its optimal rate. I like the direction that this is going. The nitrifying bacteria reproduce to the point were they reach the carrying capacity of the system (with one of the limiting factors being ammonia). By lowering the level of ammonia, we might be slowing the reproduction rate. And because the rate of ammonification should remain the same, the ammonia levels would continue to rise (canceling out the lowering effect of the water change). Since there is still an ample amount of ammonia in the system, the bacteria population should continue to increase (although possibly at a slower rate than the bacteria in the system without water changes). Eventually, the population would still increase enough to process more ammonia than the system produces. Which is where, I believe, the test container is at now. Link to comment
seabass Posted August 1, 2009 Author Share Posted August 1, 2009 Day 25 Test Results: Ammonia (NH4+), test container: 0.15 mg/L Ammonia (NH4+), control container: 0.05 mg/L Nitrite (NO2-), test container: 1 mg/L Nitrite (NO2-), control container: 1 mg/L Nitrate (NO3-), test container: 2 mg/L Nitrate (NO3-), control container: 10 mg/L Link to comment
seabass Posted August 2, 2009 Author Share Posted August 2, 2009 Day 26 Test Results: Ammonia (NH4+), test container: 0.05 mg/L Ammonia (NH4+), control container: 0.01 mg/L Nitrite (NO2-), test container: 0.5 mg/L Nitrite (NO2-), control container: 1 mg/L Nitrate (NO3-), test container: 1 mg/L Nitrate (NO3-), control container: 5 mg/L API ammonia tests: Seachem ammonia, nitrite, and nitrate tests: Closeup of Seachem ammonia sensors: Note: The charts now have a day 29. This is because I started on Day 1 (versus Day 0). Link to comment
Mr. Fosi Posted August 2, 2009 Share Posted August 2, 2009 Looks like things are converging. Link to comment
seabass Posted August 3, 2009 Author Share Posted August 3, 2009 Day 27 Just two more days to go, and today was the 13th (and final) water change for the test container. NH4+ is not detectable (in either container) with the API ammonia test kits. Test Results: Ammonia (NH4+), test container: 0.05 mg/L Ammonia (NH4+), control container: 0.01 mg/L Nitrite (NO2-), test container: 0.1 mg/L Nitrite (NO2-), control container: 0.5 mg/L Nitrate (NO3-), test container: 1 mg/L Nitrate (NO3-), control container: 10 mg/L Link to comment
seabass Posted August 4, 2009 Author Share Posted August 4, 2009 Day 28 One more day remaining. Ammonia is now hardly detectable in either container. Comments and final pictures will be posted tomorrow. Test Results: Ammonia (NH4+), test container: 0.01 mg/L Ammonia (NH4+), control container: 0.01 mg/L Nitrite (NO2-), test container: 0.1 mg/L Nitrite (NO2-), control container: 0.5 mg/L Nitrate (NO3-), test container: 1 mg/L Nitrate (NO3-), control container: 10 mg/L Notes: I will be heading out of town early Friday morning and won't be able to continue top offs or testing. Out of curiosity, I will continue the experiment for an additional day (topping off both containers, performing a water change on the test container, and adding food pellets to both). I'll take readings on Thursday and top off both containers for the last time. When I get back on Tuesday, I'll take the final readings on both containers and post the results. Link to comment
seabass Posted August 5, 2009 Author Share Posted August 5, 2009 Day 29 Thanks for following along and for all the suggestions. I tried to be as accurate as possible and post pictures to make it easier to follow along. I hope that this experiment provides some insight as to how water changes affect the nitrogen cycle. Test Results: Note: Seachem NH4+ tests were not performed on day 2, which might have indicated levels below 0.25 mg/L Data: "Day:",1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28 ,29 "NH4+ test:",0,0,0.3,0.5,1,1,1,1,1,1,1,1,1,1,1,0.5,0.5,1,1,1,1,0.5,0.25,0.15,0.15,0.05, 0.05,0.01,0 "NH4+ ctrl:",0,0,0.3,0.5,1,1,1,1,1,1,1,1,1,1,1,0.5,0.25,0.25,0.25,0.25,0.1,0.15,0.15,0. 05,0.05,0.01,0.01,0.01,0.01 "NO2- test:",0,0.1,0.1,0.1,0.5,1,1,0.5,1,1,1,1,0.5,1,2.5,2.5,2.5,2.5,2.5,2.5,1,1,1,0.5, 1,0.5,0.1,0.1,0.1 "NO2- ctrl:",0,0.1,0.1,0.5,1,2.5,2.5,1,2.5,5,5,10,10,10,10,10,5,2.5,2.5,1,0.5,1,1,0.5,1 ,1,0.5,0.5,0.5 "NO3- test:",0,0.2,1,1,1,1,2,2,2,2,2,2,2,2,5,2,2,2,2,2,2,2,2,1,2,1,1,1,1 "NO3- ctrl:",0,0.2,1,1,2,2,5,5,10,10,10,20,20,10,20,10,10,10,10,5,5,5,5,5,10,5,10,10,10 Final Pictures: API ammonia tests on samples from the test and control containers As a reference, I also tested water from my reef tank and the experiment's water change bucket I had assumed that the sample from the water change bucket would be free of NH4+ Seachem ammonia tests Closeup of Seachem ammonia sensors Seachem nitrite tests Seachem nitrate tests Seachem pH tests (test=8.0, ctrl=8.0, reef=8.2, WC=8.2) Test containers Food pellets Conclusions: While it is difficult to make definite conclusions without repeating the experiment a number of times, I still believe that some insight can be drawn from this data. It appears that water changes might prolong the drop off of ammonia; however, they seem to help lower ammonia once the drop off of NH4+ begins. One can speculate that the reduction of ammonia slows the reproduction of nitrifying bacteria, but not the rate of ammonification. This could explain why the ammonia levels were not reduced even though water changes temporarily lowered the presence of NH4+. Test data could have been influenced by all or some of the following: • misreading color matching tests (including unintentionally anticipating trends) • one or more variables affecting the results (like the rate of ammonification or environmental conditions) • contaminants being introduced to the containers or test samples • the ammonification rate of the food pellets is unknown, and might vary from bucket to bucket • the breakup of food pellets was uneven between buckets This might be due to disturbances from water changes, breakdown from bacteria, or flow patterns from the powerheads. Grinding food pellets or using premeasured ammonium might help eliminate this variable. I encourage others to repeat this test and share their results, as individual results could vary substantially. In addition, variations of this test could provide additional insights. Other possible experiments might include: • larger but less frequent water changes • ammonium versus ammonification of food pellets • plastic substrate (or dry sand) versus live sand • introducing the entire source of ammonia at the beginning of the experiment Thanks Again: I hope everyone enjoyed this experiment as much as I have. Link to comment
skimlessinseattle Posted August 6, 2009 Share Posted August 6, 2009 I have been wanting to see data on this for a long time. Excellent job. I have always believed that water changes slow the population growth of nitrifying bacteria, extending cycle time, but haven't seen any data on it. I agree with the speculation you make and would love to see a repeat! Link to comment
Mr. Fosi Posted August 6, 2009 Share Posted August 6, 2009 Good job. Now the other slackers need to get their data in. Link to comment
joe1958 Posted August 6, 2009 Share Posted August 6, 2009 So the test shows that to start the cycle you should do water changes ,just maybe not as frequently. Is this correct? Link to comment
seabass Posted August 6, 2009 Author Share Posted August 6, 2009 Thanks guys! Joe, to me, the data indicates that you should wait to perform water changes until after the ammonia level starts to drop. Once NH4+ starts dropping on its own, then water changes might help to lower the ammonia level even faster (along with lowering the level of nitrate). Note: Based on the limited data, this staged cycle method might help to shorten the cycle and result in better water quality. A third bucket, testing this cycle method, would be a good addition to the experiment. Link to comment
fewskillz Posted August 6, 2009 Share Posted August 6, 2009 Awesome! Thanks for all your hard work on this seabass. Link to comment
seabass Posted August 6, 2009 Author Share Posted August 6, 2009 Thanks fewskillz! Based on theory alone, I've been a proponent of the soft cycle since 2004. But after numerous threads debating the theory of the cycle, I decided that actual data was needed. To be honest, I liked the idea of a soft cycle and wanted/expected to see it reduce ammonia during the cycle (without substantually extending its duration). This experiment's data seems to challenge both the classic cycle method (no water changes at all) as well as the soft cycle method (water changes throughout). I'd like to see some supporting data, but it appears that a staged method (no water changes until ammonia levels start to drop) might yield the best results. Link to comment
seabass Posted August 6, 2009 Author Share Posted August 6, 2009 Day 30 - Bonus Data I'm heading out of town tomorrow; however, out of curiosity, I decided to unofficially extend the experiment another day. So yesterday I topped off the containers, performed a water change on the test container, and added the daily food pellets. I was unable to detect ammonia in either container today (see results below). I won't be able to top off the buckets or add food pellets, but I'm leaving the powerheads run while I'm gone. Just for fun, I'll post test results when I get back on Tuesday. Test Results for Day 30: Ammonia (NH4+), test container: 0 mg/L Ammonia (NH4+), control container: 0 mg/L Nitrite (NO2-), test container: 0.1 mg/L Nitrite (NO2-), control container: 0.5 mg/L Nitrate (NO3-), test container: 0.2 mg/L Nitrate (NO3-), control container: 5 mg/L Link to comment
hcsceo Posted August 6, 2009 Share Posted August 6, 2009 Great work seabass. This is really good information. Link to comment
seabass Posted August 7, 2009 Author Share Posted August 7, 2009 Thanks hcsceo. I'll check back in and report on Tuesday. Link to comment
Whacked Posted August 10, 2009 Share Posted August 10, 2009 interesting stuff. I'm cycling my 40B using 100% base rock and sand. Never cycled a tank like that before. Link to comment
seabass Posted August 11, 2009 Author Share Posted August 11, 2009 Thanks Whacked and ribbie! I'm back from my trip; here are the results prior to tearing down the experiment: Ammonia (NH4+), test container: 0 mg/L Ammonia (NH4+), control container: 0 mg/L Nitrite (NO2-), test container: 0 mg/L Nitrite (NO2-), control container: 0 mg/L Nitrate (NO3-), test container: 0.2 mg/L Nitrate (NO3-), control container: 5 mg/L Notice that nitrite levels have zeroed out. In order to help validate the results, I will be duplicating this experiment with the addition of a third bucket utilizing a dual stage cycle method (no water changes until the ammonia spike starts to come down on it's own, then frequent water changes until all levels are within acceptable ranges). Since this will be a new experiment, I will start a new thread that links to this one. Link to comment
seabass Posted August 12, 2009 Author Share Posted August 12, 2009 I just broke down the buckets and had to share. I wish I had my camera with me. I was hoping to use the sand as cured sand. However, after siphoning out the gunk, I ended up rinsing it thoroughly in tap water. There were places where the food was piled up over a half an inch deep. It was gelled together in a bacterial colony and was turning black. It didn't smell very good either (there was a distinct sulfur smell). Part 2: Water Changes During the Cycle is a followup to this experiment that tests the soft cycle, staged cycle, and classic cycle methods. Link to comment
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