blueether Posted March 6, 2012 Report Share Posted March 6, 2012 In the last thread I had about the ammonia spike I had I mentioned I had a DSB. This DSB has no snails/worms etc to turn it over but it still looks to be doing a fine job at lowering nitrates to near 0. There are no plants in there apart from a small amount of dust algae/diatomes on the glass, a very small amount of BBA on one bit of drift wood and some cynobacteria on another bit of wood. There was about 20+ ppm nitrate on the 25/2 before a 25% W/C and on the 1/3 there was below 20ppm tonight there is near enough to 0 nitrates in the tank. During the ammonia spike (and low pH, tested at or below 6) this process seemed to have stopped or slowed right down. Has anyone else played with a DSB on a non-planted tank and had similar results? Quote Link to comment Share on other sites More sharing options...
hovmoller Posted March 6, 2012 Report Share Posted March 6, 2012 Interresting... I can't remember ever having been taught in biology that anaerobic conditions were good in any meassure... so I don't really understand how this is a benefit in a sand bed with no sand turning critters in it? Can you enlighten me with the theory behind this? :sage: Quote Link to comment Share on other sites More sharing options...
blueether Posted March 6, 2012 Author Report Share Posted March 6, 2012 I have read that they (anaerobic DSB) are "killers" (hydrogen sulfide/sulphate) an also that the critters actually stop DSB working to their best. I will try and find the link to one that states the latter. Quote Link to comment Share on other sites More sharing options...
spoon Posted March 6, 2012 Report Share Posted March 6, 2012 nitrate is utilised by anaerobic bateria which turn it into nitrogen gas which escape the water as oxygen is dissolved the snails etc living in there help the nitrogen to escape Quote Link to comment Share on other sites More sharing options...
GrahamC Posted March 6, 2012 Report Share Posted March 6, 2012 Hard to imagine the mechanism if there is no way for the water to pass thru the DSB without any critters to aid it. Have you repeated the testing? Some people recommend shaking the nitrate tube for 2 mins instead of 1 min. And others make up calibration solutions since this particular test can be off on occasion. Quote Link to comment Share on other sites More sharing options...
blueether Posted March 6, 2012 Author Report Share Posted March 6, 2012 Graham, there are two 5000 l/h wavemakers that pass water over the sand, so I would suspect that there is a slight head where the DSB starts to build up - this is where the flow from the wavemakers no longer move the sand. Graham, I also wanted to get others thoughts on how this is/might be working. Pic of some of the DSB at the front of the tank, deeper further back Quote Link to comment Share on other sites More sharing options...
Ira Posted March 6, 2012 Report Share Posted March 6, 2012 Hard to imagine the mechanism if there is no way for the water to pass thru the DSB without any critters to aid it. Have you repeated the testing? Some people recommend shaking the nitrate tube for 2 mins instead of 1 min. And others make up calibration solutions since this particular test can be off on occasion. The water diffuses through just fine without any critters. It's just slow. And I found similar tests with my tank that made me think it might be working as a DSB. Quote Link to comment Share on other sites More sharing options...
livingart Posted March 6, 2012 Report Share Posted March 6, 2012 not only inverts but also microscopic life burrows through and turns over the sand this ensures that the aerobic areas of the DSB are turned over frequently supplying more oxygenated water and nutrients to feed the bacteria in this zone the same process also turns over the sand in the anaerobic areas, which frees the nitrogen gas trapped and allows more nitrate rich/oxygen deprived water to enter the zone for bacteria to feed on Quote Link to comment Share on other sites More sharing options...
GrahamC Posted March 6, 2012 Report Share Posted March 6, 2012 Ah, ok. I found this link which goes into depth ( 3 inches! ) on the subject http://www.wetwebmedia.com/ca/volume_7/volume_7_1/dsb.html so I might give this a go too. Just need another couple of more inches of sand .. I hope the Placemaker's sand I am using is the right particle size. Quote Link to comment Share on other sites More sharing options...
blueether Posted March 6, 2012 Author Report Share Posted March 6, 2012 That is one of the ones I was just re-reading, but not the one I wanted to find Just measured how deep the sand is and for about 1/3 of the floor area of 1200*600 the sand varies from ~75mm to ~120mm. The top 5mm-10mm is quite mobile with the flow and the bullies/torrent fish moving it around Quote Link to comment Share on other sites More sharing options...
livingart Posted March 6, 2012 Report Share Posted March 6, 2012 marine DSB minimum depth is 4inch recommended i have 3+inch and it seems to work on tropical and cold system Quote Link to comment Share on other sites More sharing options...
Squirt Posted March 6, 2012 Report Share Posted March 6, 2012 So with a DSB I can get away with not doing water changes? :slfg: :digH: (just kidding) Quote Link to comment Share on other sites More sharing options...
GrahamC Posted March 6, 2012 Report Share Posted March 6, 2012 You'll still need to replace the minerals consumed by the fish and other things. Quote Link to comment Share on other sites More sharing options...
Squirt Posted March 6, 2012 Report Share Posted March 6, 2012 [joking]So if I chucked some chemicals (or minerals and other consumables consumed by fish) in the water + had a DSB I could get away with no water changes ? :sml1: sorry :smot: [/joking] But on another note, if you ran a DSB in a sump COULD it reduce the amount of water changes you would have to do? Providing you did a water change every week and a half or so, to keep mineral levels up and other beneficial things that are added when a water change is done. Quote Link to comment Share on other sites More sharing options...
GrahamC Posted March 6, 2012 Report Share Posted March 6, 2012 If the purpose is for nitrate reduction then I would suppose so. What do the guys who actually run DSBs do? Another way to do nitrate reduction is to put the water thru a hydroponics bed ie. run an aquaponics system. From what I've read they don't do as many PWCs. But they also eat their fish! Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted March 6, 2012 Report Share Posted March 6, 2012 In nature this would exist at a lot of beaches and the bottom of streams but the bio load would be way less than what we are dealing with. There will be other unwanted chemicals around as well as those being dealt with so water changes will get rid of them Quote Link to comment Share on other sites More sharing options...
hovmoller Posted March 6, 2012 Report Share Posted March 6, 2012 I can see that you might have some benefitial DSB (Danske Stats Baner = Danish State Railways) going on in your tank that would explain the zero NO3 but I still think there is too much risk in having too deep a substrate in a freshwater tank. Some anaerobic bacteria will start converting NO3 back to ammonia and you'll be in serious trouble. Maybe I'm missing the point here... maybe you are not trying to create a DSB effect but you are wondering if you have by coincident made one? Quote Link to comment Share on other sites More sharing options...
livingart Posted March 6, 2012 Report Share Posted March 6, 2012 Some anaerobic bacteria will start converting NO3 back to ammonia and you'll be in serious trouble. had that happen in a mangrove brackish water set up too much organic matter in the sand that came with their root system Quote Link to comment Share on other sites More sharing options...
blueether Posted March 6, 2012 Author Report Share Posted March 6, 2012 I can see that you might have some benefitial DSB (Danske Stats Baner = Danish State Railways) going on in your tank that would explain the zero NO3 but I still think there is too much risk in having too deep a substrate in a freshwater tank. Some anaerobic bacteria will start converting NO3 back to ammonia and you'll be in serious trouble. Even if you had partial reduction to NO2- or fully back to NH3/NH4 in the anaerobic zone it will have to pass back through the aerobic zone where we will have oxidation happening via bacteria (or archaea). Then is it does get into the water column there is the bio-filter Maybe I'm missing the point here... maybe you are not trying to create a DSB effect but you are wondering if you have by coincident made one?It wasn't so much that i wanted to create a DSB, although I did have that at the back of my mind, it was partially aesthetics and need for atleast 50mm for a freshwater mussel. About 1/3 of the sand moved the the far end when I installed the two wavemakers. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted March 6, 2012 Report Share Posted March 6, 2012 I have not tested the chemistry but have not seen any problems whith landscaping fresh water tropicals with sand fron 50mm to 150mm in depth in heavily planted tanks and nothing other than microbes to disturb it. I had one operating with an undergravel filter for a long time as well (in the shallower area). Quote Link to comment Share on other sites More sharing options...
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