ph fishless cycle question

[dwilder]

i could use help finding a thread or new comments on a ph crash im having while cycling a new tank.i've been cycling my new tank for about three weeks ammonia started dropping to 0 my nitrites spiked then have been slowly dropping almost to 0 but not quite there yet.now this morning i tested my water and was showing 1ppm of ammonia when usually its 0 after about 8 hours and my ph was 6.5.my water is pretty hard and after its aged the ph stays at 7.8 in my other tanks. i appreciate any help i know i've read about ph drops while cycling a tank just cant remember why or what to do about it

[Don Trinko]

I'm certainly not an expert on this but Some ph crashes are caused by insuficient buffering capability.( low KH ) If your KH is very low it can cause this. (3 is OK I'm not sure how low it needs to be to cause trouble) Don T.

[kaceyo]

Your pH dropping to 6.5 is not a crash and shouldn't effect the cycling process. You can do a large wc (50% to 100%) just as you would if there were fish in it and that should rebuild the KH so the ph doesn't continue to drop. Just replace the ammonia after the wc.

Kacey

[Hans Kloss]

i've read about ph drops while cycling a tank just cant remember why or what to do about it

Final product of ammonia oxidizing performed by bacteria is nitric acid. Excess of this acid (high nitrate level) resulted in kh and pH lowering. High nitrates may inhibit bacteria growth so keep it at 50 ppm level, not more. Good water aeration and high temperature are also beneficial to speed up a cycling process.
Hans

[Graham]

Interesting that the same kinds of conservations go on on different boards

The use of bead filters and thier relationship to alkalinity comsumption is going on, on the KoiShack board at the moment

Nitrification

55NH4+ + 76O2 + 109HCO3- -----> C5H7O2N + 54NO2- + 57H2O + 104H2CO3

400NO2- + NH4+ + 4H2CO3 + HCO3- + 195O2 -----> C5H7O2N + 3H2O + 400NO3-

The bicarbonate is directly consumed by the bacteria in the nitrification process (primarily in the first step). Biomass and carbonic acid (CO2 really) are formed from the bicarbonate.


http://koishack.com/forums/index.php?showtopic=12085&st=20

[dwilder]

thankyou for comments .just tested water when i got off from work ph has climbed to 7.4 ammonia is still at 1ppm like it was last night not sure why?the filter is a magnum 350 with the two biowheels on a 75 gallon tank temp is 82deg.still have to check nitrates but i guess ill do water change then add the ammonia back