Hi all,
Because of these limitations reef keepers have tried various different techniques for biological filtration (trickle filters, plenums, denitrifying coils, deep sand beds etc), but I think the most popular option is now live rock (which will support both aerobic and anaerobic filtration) and a protein skimmer (to remove potential sources of nitrogen). I'm not a marine keeper but I know various members are (Foxfish, BigTom etc), and they should be able to tell you more. A sort of freshwater equivalent would be a HMF, where it is possible to have <"simultaneous nitrification and denitrification">.
Another issue is that sea water has a known amount of chloride ions (Cl-) present (about 17ppt), and this means that this can be factored into nitrate testing kits. In fresh water we have problems with monovalent anions like Cl- interfering with NO3- testing, partially because we don't know what the Cl- ion content of the water is.
In a fresh water planted tank it is a bit different. We can use floating and emergent plants with access to aerial CO2 (or we can add CO2 to submerged plants). Non CO2 limited plants have the ability to take up large amounts of nitrogenous compounds (including NH4+ as well as NO3-), meaning that levels of nitrates tend to fall over time, rather than rise.
Because we have easy access to water changes and plants we can take a different approach to biofiltration. Ammmonia (NH3) and nitrite (NO2-) are much more toxic than nitrate (NO3-), so our principal aim is to convert all the ammonia into less toxic compounds as rapidly as possible.
Plants directly take up NH3/NH4+ and they also are net oxygen suppliers, and biological filtration is an oxygen intensive process. In a planted tank you can just ensure that all the filter media is aerobic and leave the plants to mop up the nitrate, we don't need to try and get the tricky balance between aerobic nitrification and anaerobic denitrification.
cheers Darrel
Yes, it is a bit different if you keep a reef aquarium, water changes become more expensive and time consuming, you don't have access to many higher plants (only really <"Mangrove and Sea grasses">) to act as a phytofilter, and very low levels of nitrogen and orthophosphate encourage the growth of algae that most reef keepers don't want.
Because of these limitations reef keepers have tried various different techniques for biological filtration (trickle filters, plenums, denitrifying coils, deep sand beds etc), but I think the most popular option is now live rock (which will support both aerobic and anaerobic filtration) and a protein skimmer (to remove potential sources of nitrogen). I'm not a marine keeper but I know various members are (Foxfish, BigTom etc), and they should be able to tell you more. A sort of freshwater equivalent would be a HMF, where it is possible to have <"simultaneous nitrification and denitrification">.
Another issue is that sea water has a known amount of chloride ions (Cl-) present (about 17ppt), and this means that this can be factored into nitrate testing kits. In fresh water we have problems with monovalent anions like Cl- interfering with NO3- testing, partially because we don't know what the Cl- ion content of the water is.
In a fresh water planted tank it is a bit different. We can use floating and emergent plants with access to aerial CO2 (or we can add CO2 to submerged plants). Non CO2 limited plants have the ability to take up large amounts of nitrogenous compounds (including NH4+ as well as NO3-), meaning that levels of nitrates tend to fall over time, rather than rise.
Because we have easy access to water changes and plants we can take a different approach to biofiltration. Ammmonia (NH3) and nitrite (NO2-) are much more toxic than nitrate (NO3-), so our principal aim is to convert all the ammonia into less toxic compounds as rapidly as possible.
Plants directly take up NH3/NH4+ and they also are net oxygen suppliers, and biological filtration is an oxygen intensive process. In a planted tank you can just ensure that all the filter media is aerobic and leave the plants to mop up the nitrate, we don't need to try and get the tricky balance between aerobic nitrification and anaerobic denitrification.
cheers Darrel
