Does ph of 2 disinfect?

[wooden_reefer]

I soak heaters and powerheads with diluted muriatic acid, ph is at the most 2, may be 1.5, for a least one hour.

Does this ph also disinfect?

Do bacteria and virsus survive ph of 2?

 

[wooden_reefer]

bump

 

[chuckreef]

Probably kills most organisms. Some spores (bacterial and algae) and viruses in certain states may survive, but that's a big may presuming this is RO/DI water and the organisms of concerna are marine species.

 

[KarlBob]

At 25C, HCl (muriatic acid) at pH 2 should be about 0.01 Molar, and pH 1.5 would be about 0.05 M. (Both of these calculations assume no buffering effects, just pure HCl in pure H2O.)

I found one reference online saying that acids are bactericidal at pH < 3, but not much else.

 

[Randy Holmes-Farley]

What are you trying to kill?

Some bacteria can survive pH 2 for 2.5 hours:

Adaptive responses of Salmonella enterica serovar Typhimurium DT104 and other S. Typhimurium strains and Escherichia coli O157 to low pH environments. de Jonge, R.; Ritmeester, W. S.; van Leusden, F. M. Microbiological Laboratory for Health Protection, National Institute for Public Health and the Environment, Bilthoven, Neth. Journal of Applied Microbiology (2003), 94(4), 625-632.

Abstract

Cattle are a known main reservoir for acid-resistant Escherichia coli O157 and Salmonella enterica serovar Typhimurium DT104. We studied the response of S. Typhimurium DT104 to extreme low pH environments and compared their response to that of acid-resistant E. coli O157 and other S. Typhimurium phage types. Bacteria were grown in nutrient-rich medium and subsequently acid challenged at pH 25. We found that stationary phase cultures of various S. Typhimurium strains were able to survive a challenge for 2 h at pH 25. As in E. coli, the ability of S. Typhimurium to survive at pH 25 was shown to be dependent on the presence of amino acids, specifically arginine. The amt. of proton pumping H+/ATPase, both in E. coli O157 and S. Typhimurium strains, was lower when grown at pH values <6 than after growth at pH 75. Cyclo fatty acid content of membranes of bacteria grown at pH values <6 was higher than that of membranes of bacteria grown at pH 75. Various S. Typhimurium strains, both DT104 and non-DT104, are able to survive for a prolonged period of time at pH 25. Their response to such low pH environment is seemingly similar to that of E. coli O157. Food-borne pathogens like S. Typhimurium DT104 and E. coli O157 form a serious threat to public health since such strains are able to survive under extreme low pH conditions as present in the human stomach. The emergence these acid-resistant strains suggests the presence of a selection barrier. The intestinal tract of ruminants fed a carbohydrate-rich diet might be such a barrier.




While it doesnt' cover all possible species of bacteria, this ancient article seems to show the range of pH where bacteria become unable to thrive:

The relation between the acid-base equilibrium and the gastric bacterial flora. Hood, Marion; Arnold, Lloyd. American Journal of Digestive Diseases and Nutrition (1937), 4 95-9.

Abstract

Cultures of the contents of fasting stomachs showed a bacterial growth that paralleled the pH in the following manner: below pH 1.0 the contents were sterile; at pH 1.0-2.0 there were occasional colonies; at pH 3.0 was the borderline of bacterial growth; above pH 3.0 there was heavy bacterial growth. Alterations in the pH of the gastric contents produced by ingestion of dil. mineral or org. acids were assocd. with a decrease in the viable bacterial flora. The ingestion of buffered alk. solns. was assocd. with an increase in the viable gastric flora.

 

[wooden_reefer]

Probably I want to kill pathogenic bacteria that cause my fish misery.

I guess bacteria that can survive stomach acid will not be killed at a ph of 2.

Thanks

 

[Randy Holmes-Farley]

I'd aim for pH 1 if you want to be more sure.

 

[qfrisco]

How about just soaking in bleach?

 

[wooden_reefer]

How about just soaking in bleach?

An extra step I hope to avoid.

 

[qfrisco]

An extra step I hope to avoid.

Agreed. It is what I do though, and you're right, at least because of my paranoia, I let something that I've soaked in bleach dry at least overnight before I'll put it back in my tank.

 

[JHemdal]

Woodenreefer,

IDK, the gut bacteria in humans seems pretty content at living at a pH of 2 or so in stomach acid.

Why sterilize items that will be returned to the tank that they came from? They'll just be reinnoculated by the bacteria that remained behind.

If you are talking about cross contamination between water systems, then this can be a concern (although very over-rated IMO). A 1:10 sodium hypochlorite soak is usually the best choice, followed by copious rinsing and air drying before being used in the new system. There is always the issue that many "bleaches" on the market today are no longer just sodium hypochlorite and water. They add all sorts of gels, surfacants, perfumes and other things. There is also the issue that bleach solutions degrade many materials such as steel and nylon - but acids can affect their own class of materials.

Jay

 

[wooden_reefer]

Woodenreefer,


Why sterilize items that will be returned to the tank that they came from?
Jay

You have only one tank?

I have multiple DT's and also a couple of QT's that service new livestock repeatedly.

 

[billsreef]

If you are talking about cross contamination between water systems, then this can be a concern (although very over-rated IMO).

I'm afraid I can't agree with you on this one. I've seen some pretty nasty cross contamination in my lab as the result of an undergrad not following protocol to dip nets between systems. A strong solution of Iodophore (available from aquaculture supply houses and homebrew stores) works very well with at least 15 minutes contact time. It does stain things, but doesn't have any of the corrosive problems associated with bleach. There are other disinfectants that work well, but are only available in bulk and expensive. So for hobbyist use, I'd go with Iodophore or Jay's weak bleach solution.

 

[Chemistry Guy]

How about just soaking in bleach?

In the context of this thread I'd like to remind everyone to never ever ever mix bleach and acid. It'll produce a very toxic gas. I wouldn't even move a heater from a bleach solution to an acid solution (or vice versa) for example. If you have muriatic acid, don't even keep it in the same room as bleach. The vapors can and will escape the bottles over time.

 

[wooden_reefer]

In the context of this thread I'd like to remind everyone to never ever ever mix bleach and acid. It'll produce a very toxic gas. I wouldn't even move a heater from a bleach solution to an acid solution (or vice versa) for example. If you have muriatic acid, don't even keep it in the same room as bleach. The vapors can and will escape the bottles over time.

Thanks

I almost did but at least I was aware of the possibility that some thing bad can happen in combination.

 

[JHemdal]

woodenreefer,

I assumed that since you were using acid baths, you were doing so to remove hardness scale, prior to returning that item to the tank it came from....thus my point of "why worry about bacteria?". If the item isn't going right back to the same tank after you acid clean it, why not just air dry it?

Bill,
woodenreefer seemed to be concerned with removing "pathogenic bacteria" from the items. Net dips have an important function in removing protozoan and metazoan contaminants, but their need for controlling bacterial problems is HIGHLY overrated. Most of the aquarium fish "pathogens" are ubiquitous - you can isolate Aeromonas and Pseudomonas from almost every aquarium. Likewise, Mycobacterium marinum can be cultured from most frozen fish foods, and is found in many aquariums. Is there a chance that one tank in a home has a virus or rare bacterial problem and the other tanks in the space don't? It is possible I suppose, but aeresol transport of small particles is difficult to control anyway - so the bug is going to make it around the space on its own....
That said, we found that the 1:10 bleach solution is effective in real world applications in controlling aerobic bacteria of all types.


Jay

 

[billsreef]

Bill,
woodenreefer seemed to be concerned with removing "pathogenic bacteria" from the items. Net dips have an important function in removing protozoan and metazoan contaminants, but their need for controlling bacterial problems is HIGHLY overrated. Most of the aquarium fish "pathogens" are ubiquitous - you can isolate Aeromonas and Pseudomonas from almost every aquarium. Likewise, Mycobacterium marinum can be cultured from most frozen fish foods, and is found in many aquariums. Is there a chance that one tank in a home has a virus or rare bacterial problem and the other tanks in the space don't? It is possible I suppose, but aeresol transport of small particles is difficult to control anyway - so the bug is going to make it around the space on its own....
That said, we found that the 1:10 bleach solution is effective in real world applications in controlling aerobic bacteria of all types.


Jay

Quite true. It's the protozoans and metazoans that scare me. The bacterial infections are typically all secondary infections to parasite damage or handling damage. In all the samples I've sent to our resident pathologist, any bacterial problems have always been environmentally common opportunistic pathogens that can only become infectious due to some other initial problem.

 

[wooden_reefer]

woodenreefer,

I assumed that since you were using acid baths, you were doing so to remove hardness scale, prior to returning that item to the tank it came from....thus my point of "why worry about bacteria?". If the item isn't going right back to the same tank after you acid clean it, why not just air dry it?

Bill,
woodenreefer seemed to be concerned with removing "pathogenic bacteria" from the items. Net dips have an important function in removing protozoan and metazoan contaminants, but their need for controlling bacterial problems is HIGHLY overrated. Most of the aquarium fish "pathogens" are ubiquitous - you can isolate Aeromonas and Pseudomonas from almost every aquarium. Likewise, Mycobacterium marinum can be cultured from most frozen fish foods, and is found in many aquariums. Is there a chance that one tank in a home has a virus or rare bacterial problem and the other tanks in the space don't? It is possible I suppose, but aeresol transport of small particles is difficult to control anyway - so the bug is going to make it around the space on its own....
That said, we found that the 1:10 bleach solution is effective in real world applications in controlling aerobic bacteria of all types.


Jay

Do you think drying will kill all or nearly all pathogenic bacteria?

 

[Randy Holmes-Farley]

Oven baking would, or boiling water, but simple air drying will not.

 

[JHemdal]

Air drying is widely used by aquaculturists for ponds....

Jay