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Re: [APD] NH4

Lightly plant => less ability to keep the NH4 low.
  More plants= better NH4 supression.
  No plants, very little ability to supress algae.
  Less biomedia= less ability to keep the NH4=> No2=> NO3 cycled rapidly.
  Add mulm in the start up phase =>  no cyclying peroid(and no algae)
  Add ferts right away=> plant health is good, better uptake of NH4
  Uproot established tank too much, deep mulm has some NH4 as the plant  and fish waste as they are decomposed from organic N into mineral  inorganic forms.
  If you do a water change right away after adding NH4,  or doing the uproot tank rework etc, then you do not get algae.
  Activated carbon, zeolite etc can be used to remove NH4 and later provided biomedia.
  High O2 does not depress algae growth any more than plant growth, see  photorespiration, this occurs in _both_ plants and algae. Bleach and  other strong oxidizers are killing the smaller organism, not because  they are more suspectible to oxygen radicals internally. A BB gun will  kill a mouse, but not an elephant. I need far more drugs to have the  same effect as a 2 year old kid. 
  This was discussed in depth here years ago.
  I showed that adding high levels of O2 did not reduce any algae biomass  as measured by Chl a, as well as high CO2 + high O2 nor any comination  of CO2 and O2 at ambient nor high levels. Species composition changed,  but the biomass was the same. nutrients were non limiting the entire  time(3 weeks x 2 blocks)
  Once algae is induced, then it (the now "adult algae") will use the NO3  to grow well.Once there, it has to make a go of it, if it's justr a  spore, it can hang out and wait till there are greener pastures.
  But NO3 alone will not induce the algae whether it is at 2ppm or 20ppm or 80ppm when you have a bunch of plants.
  Fish only tanks have no export of NO3, nor NH4 other than  transformation from NH4=>NO3, but it all starts as NH4 in fish  tanks, (unless the tap has a lot of NO3 etc), fish only tank owners  never add KNO3:-)
  So they thend to think NO3 = algae, bad conditions etc.
  That's a reasonable view also given their needs/observations.
  But we have plants............
  A sudden decline of CO2 can reduce the plants ability to take up NH4  that is produced by fish and the bacteria do not have enough time to  respond.
  A sudden decline of PO4 can cause a similar thing, but the effect from  NO3 is more profound. Most plants and algae can handle the PO4  limitation.
  Few plants do well when you have maintained the CO2 high then drop it rapidly.
  Then algae go to town.
  Once there, it's rough getting rid of them. But if you attack it, then  beat them back, then correct the issue, the algae will not keep growing.
  Liz wrote:
  >I know we've been told that allelopathy isn't at play but if the plants
  >hemselves are not putting out chemicals that are suppressing algae, then
  >ow can we account for the fact that the aquarium with plants doesn't grow
  >lgae at the rate of the tank without plants with the same level of
  Algae can grow well, once the spores are established.
  Think of spores like seeds.
  Why don't "seeds" germinate all the time?
  They will germinate in response to certain environmentally favorable conditions.
  Fire, water/rain, temprature, ligth etc.
  Algae live in a different seasonal environment.
  They respond to CO2 to NH4, fast declines of O2, actually low O2( below  50% saturation) like after disturbing your substrate a great deal if  it's had enough time to build up a bunch of mulm.
  A simple way to make an anaerobic water sample is shake up some  hydrosoil sediment. The same occurs when we uproot too much in our  tanks and also remove the O2 pumps that supply the gravel below, the  roots.
  You can measure the O2 before, during and after a big overhaul on a tank. 
  But high O2 does not prevent algae, but pretty low can help.
  Nothing does it like NH4(too much allows algae to eat this nutrient "candy") and varying the CO2(confuses the plants). 
  If you do a large water right after doing a big water change, then  the  tank does not experience the low O2 for longer peroids nor  any NH4.
  So you don't get algae.
  Try it without doing the water change vs the water change and dose the same nutrients(NO3, PO4 etc) for each.
  You'll see a pattern I've described.  
  >Assuming a
  >high light tank with adequate CO2 supplementation, which tank(s) will
  >algae occur?
  All tanks will have some algae, I'll assume visible algae and plenty of plant biomass and good nutrients....
  >TANK 1: High in nutrients and detectable NH4.
  >TANK 2: High in nutrients and undetectable NH4.
  Tank 1 will have algae, you can have some NH4 and little to no algae  under a few conditions, daily large water changes is one such way, slow  dosing is another, where the NH4 is yet another (substrate vs water  column).It also depends on how much NH4, that is a harder question to  answer for a few reasons. Testing is a huge issue with that and the  time frame involved(30 hours or so) and other tank to tank variables  like plant biomass.
  It's a tougher line to say, but there is a range, but I'm leery to give  any amount as people will try it and then misapply it and folks will  kill fish and cause all sorts of algae issues.
  What might work a few times for so and so, maybe cause huge issues for others. NH4 is playing with fire.
  >Once algae is in its active reproductive stage, which tank will algae
  >growth be the fastest?
  >TANK 1: High in nutrients.
  >TANK 2: Low in nutrients.
  Once the algae are adults, both tanks will grow well, but the NH4 maybe slightly better growth of the algae.
  >Assuming poor CO2 is also a cause for algae, does it cause algae
  >directly or does it do so by facilitating the accumulation of NH4?
  >Which of the following tank(s) will produce algae?
  >TANK 1: High light, high CO2, and detectable NH4.
  >TANK 2: High light, low CO2, and detectable NH4.
  >TANK 3: High light, low CO2, and undetectable NH4.
  Tank 1 will have the highest growth rate
  Tank 2 will come in 2nd 
  Tank 3 will be last.
  I do not think it causes algae directly, it might for some species like BBA.
  In some cases, I've been able to induce algae by removing CO2 to a  4w/gal test tank that had GW prior but was otherwise doing fine.
  So gnaw on this for awhile.
  Tom Barr

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