Water Question: Low KH / PH Drop

[Rocksor]

Can someone help me , I did a clean and water chance 5 days ago and my ph is at 6 or lower , the water out of my tap is around 7-7.5 ( where I want it ) , but my tank ph won’t go up to that , I even did another water change trying to get the ph up and it didn’t do anything . A whole bottle of api ph up and it didn’t raise even a little . What do I do

you need to test your tap water ph after it is sitting in a cup for a day. That will tell you what your true tap water PH is when using a liquid test.

I would also get a GH/KH Api test to determine the tap buffering capacity and general hardness.

 

[TwoTankAmin]

Nitrification bacteria (the beneficial bacteria) start to die off below 6.0 pH. So that definitely could be a reason for your cycle not going quickly.

Absolutely false.


High-Rate Nitrification at Low pH in Suspended- and Attached-Biomass Reactors
Sheldon Tarre, Michal Green
Applied and Environmental Microbiology Nov 2004, 70 (11) 6481-6487; DOI: 10.1128/AEM.70.11.6481-6487.2004

ABSTRACT
This article reports on high-rate nitrification at low pH in biofilm and suspended-biomass reactors by known chemolithotrophic bacteria. In the biofilm reactor, at low pH (4.3 ± 0.1) and low bulk ammonium concentrations (9.3 ± 3.3 mg · liter−1), a very high nitrification rate of 5.6 g of N oxidized · liter−1 · day−1 was achieved. The specific nitrification rate (0.55 g of N · g of biomass−1 · day−1) was similar to values reported for nitrifying reactors at optimal pH. In the suspended-biomass reactor, the average pH was significantly lower than that in the biofilm reactor (pH 3.8 ± 0.3), and values as low as pH 3.2 were found. In addition, measurements in the suspended-biomass reactor, using isotope-labeled ammonium (15N), showed that in spite of the very low pH, biomass growth occurred with a yield of 0.1 g of biomass · g of N oxidized−1. Fluorescence in situ hybridization using existing rRNA-targeted oligonucleotide probes showed that the nitrifying bacteria were from the monophyletic genus Nitrosomonas, suggesting that autotrophic nitrification at low pH is more widespread than previously thought. The results presented in this paper clearly show that autotrophic nitrifying bacteria have the ability to nitrify at a high rate at low pH and in the presence of only a negligible free ammonia concentration, suggesting the presence of an efficient ammonium uptake system and the means to cope with low pH.

from https://aem.asm.org/content/70/11/6481.full


Gieseke, A., Tarre, S., Green, M., & de Beer, D. (2006). Nitrification in a biofilm at low pH values: role of in situ microenvironments and acid tolerance. Applied and environmental microbiology, 72(6), 4283–4292. https://doi.org/10.1128/AEM.00241-06

Abstract
The sensitivity of nitrifying bacteria to acidic conditions is a well-known phenomenon and generally attributed to the lack and/or toxicity of substrates (NH3 and HNO2) with decreasing pHs. In contrast, we observed strong nitrification at a pH around 4 in biofilms grown on chalk particles and investigated the following hypotheses: the presence of less acidic microenvironments and/or the existence of acid-tolerant nitrifiers. Microelectrode measurements (in situ and under various experimental conditions) showed no evidence of a neutral microenvironment, either within the highly active biofilm colonizing the chalk surface or within a control biofilm grown on a nonbuffering (i.e., sintered glass) surface under acidic pH. A 16S rRNA approach (clone libraries and fluorescence in situ hybridizations) did not reveal uncommon nitrifying (potentially acid-tolerant) strains. Instead, we found a strongly acidic microenvironment, evidence for a clear adaptation to the low pH in situ, and the presence of nitrifying populations related to subgroups with low Kms for ammonia (Nitrosopira spp., Nitrosomonas oligotropha, and Nitrospira spp.). Acid-consuming (chalk dissolution) and acid-producing (ammonia oxidation) processes are equilibrated on a low-pH steady state that is controlled by mass transfer limitation through the biofilm. Strong affinity to ammonia and possibly the expression of additional functions, e.g., ammonium transporters, are adaptations that allow nitrifiers to cope with acidic conditions in biofilms and other habitats.

from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1489657/

I can post more papers if you all want. I can also tell you I have had a cycled tank at a pH below 5.0 for my wild Altum Angels (they came into a 4.2 pH tank on day one). Today they live at 6.0 a process which took me about 6 months to achieve. I had a grand plan for cycling. It involved using a cycling tank for the sponge filters. I started them out at 7.0. Then i would drop the pH by about .2 and when they were able to process 2 ppm of ammonia in 24 hours, I dropped it another .2. AT the same time I was moving the altum tanks up from 4.2 to 6.0. The cycling of the filters and the raising of the altum tank pH was times such that I would have cycled filters for a 6.0 tank ready at about the time the angel tank hit that number.

Imagine my surprise after 6 months to fund the angel tank was cycled on its own and I never needed the filters from the bio-farm. Bear in mind that at 6.0 pH and lower, all of the ammonia in a tank is in the form of ammonium (NH4). This is way less toxic than NH3.

 

[Ardiej]

you need to test your tap water ph after it is sitting in a cup for a day. That will tell you what your true tap water PH is when using a liquid test.

I would also get a GH/KH Api test to determine the tap buffering capacity and general hardness.

I’ll do that , I don’t. Understand the sudden change tho it’s been fine for months , if test it a few days after water change or gravel clean and it would be fine