I just skimmed through this thread but from what I gather it sounds like the op doesn't regularly vacuum their gravel. Could that be the cause of the ammonia spike?
^ Good point.
Although NO DIRECT relation, at least I know, but Just remembered other possible scenario.
Only other possible scenario I could think of at this time b/n undistubed substrates and ammonia is via denitrification and nitrogen fixation process where N2 produced via
denitrification is converted to NH3 via
nitrogen fixation and when in NH4+ form (what I assume majority of toal ammonia to be in OP's tank), it will reacti with NO2 to form N2 again via "
ANAEROBIC AMMONIUM OXIDATION" which may explain absence of both NO3 and NO2 which may expalain presence steady [total Ammonia], if memory serves. Just a thought, not saying it is an actual process taking place in OP's tank but worth keeping in mind.
If this is what may also actually be taking place, OP can vacuum portion (1/4 perhaps at a time) of the substrates during wc every two or three days and monitor to detect any possible changes yielded. W/o knowing what, dont want to disturb too much which may yield worst situations/conditions.
If what DrTim said is true that there are 2 strains of Nitrosomonas, tank may need time to reestablish appropriate stains to oxidize NH3 to NO2.
Another concern I have with this scenario is the inhibition of existing Nitrospira/Nitrobacter due to presence of high [total ammonia] which may subsquently limits oxidation of NO2 to a point sudden spike of NO2 is observed as oxidation of NH3 (apparopriate Nitrosomonas) is reestablishing/ed.
Either way, try to avoid any massive/sudden changes at present condition (
pH@7.2) as we really dont know exactly what is going on with this tank.
Has small WC/less feeding shown any effects on [NH3]? Any presence of NO2?
Hope pH is very stable at 7.2 as I am more concerned with shifting of pH toward more alkaline side for whatever reasons
in presence of any [NH3].
Hope all goes well!
