How To Bring My Ph Down Safely And Effectively

[Bunchbro84]

Hello, I am back again with a new question. I have gravel that is highly suspected to be painted dolomite and my ph is at 8.2 and I would like it to be at 7.6 or possibly 7.4. My question is, how do I lower it (changing substrate to inert sand is would I would like to do along with some sort of plant fertilizer) without killing my fish. I have a 36 gallon with one rubber lip pleco, 2 red eye tetras, 3 mollies, 2 black skirt tetras, 2 ghost shrimp, a banjo catfish and 2 glowlights. I am very aware that I need schools but I have no where or one to get rid of some fish. I have a aqueon 50 gallon power filter and paramaters as last checked were ammonia 0, nitrite 0 and nitrates maybe 15 or possibly 10.
 
I need to figure this out because I hate having them living in such high ph for a community tank, right now I am using ph regulator from marineland and it seems to be helping for now.
 
I have a piece of Mopani wood in the tank and I don't know if it is helping. My tap water ph I think is 8 or 7.4 I am unsure because one test I did I left it out for like 4 days and one I left out for 1.
 
Any help is welcomed as I would love to resolve this problem.
 
 

 

[TwoTankAmin]

Where you want to go is a slippery slope. Here are the starting points:
 

 

Buffering Capacity (KH, Alkalinity)
Buffering capacity refers to water's ability to keep the pH stable as acids or bases are added. pH and buffering capacity are intertwined with one another; although one might think that adding equal volumes of an acid and neutral water would result in a pH halfway in between, this rarely happens in practice. If the water has sufficient buffering capacity, the buffering capacity can absorb and neutralize the added acid without significantly changing the pH. Conceptually, a buffer acts somewhat like a large sponge. As more acid is added, the ``sponge'' absorbs the acid without changing the pH much. The ``sponge's'' capacity is limited however; once the buffering capacity is used up, the pH changes more rapidly as acids are added.
 
Buffering has both positive and negative consequences. On the plus side, the nitrogen cycle produces nitric acid (nitrate). Without buffering, your tank's pH would drop over time (a bad thing). With sufficient buffering, the pH stays stable (a good thing). On the negative side, hard tap water often almost always has a large buffering capacity. If the pH of the water is too high for your fish, the buffering capacity makes it difficult to lower the pH to a more appropriate value. Naive attempts to change the pH of water usually fail because buffering effects are ignored.
 
In freshwater aquariums, most of water's buffering capacity is due to carbonates and bicarbonates. Thus, the terms ``carbonate hardness'' (KH), ``alkalinity'' and ``buffering capacity'' are used interchangeably. Although technically not the same things, they are equivalent in practice in the context of fishkeeping. Note: the term ``alkalinity'' should not be confused with the term ``alkaline''. Alkalinity refers to buffering, while alkaline refers to a solution that is a base (i.e., pH > 7).
 
How much buffering does your tank need? Most aquarium buffering capacity test kits actually measure KH. The larger the KH, the more resistant to pH changes your water will be. A tank's KH should be high enough to prevent large pH swings in your tank over time. If your KH is below roughly 4.5 dH, you should pay special attention to your tank's pH (e.g, test weekly, until you get a feel for how stable the pH is). This is ESPECIALLY important if you neglect to do frequent partial water changes. In particular, the nitrogen cycle creates a tendency for an established tank's pH to decrease over time. The exact amount of pH change depends on the quantity and rate of nitrates produced, as well as the KH. If your pH drops more than roughly two tenths of a point over a month, you should consider increasing the KH or performing partial water changes more frequently. KH doesn't affect fish directly, so there is no need to match fish species to a particular KH.
 
Note: it is not a good idea to use distilled water in your tank. By definition, distilled water has essentially no KH. That means that adding even a little bit of acid will change the pH significantly (stressing fish). Because of its instability, distilled (or any essentially pure water) is never used directly. Tap water or other salts must first be added to it in order to increase its GH and KH.

and then

 

Raising and Lowering pH
One can raise or lower pH by adding chemicals. Because of buffering, however, the process is difficult to get right. Increasing or decreasing the pH (in a stable way) actually involves changing the KH. The most common approach is to add a buffer (in the previous section) whose equilibrium holds the pH at the desired value.
 
Muriatic (hydrochloric) acid can be used to reduce pH. Note that the exact quantity needed depends on the water's buffering capacity. In effect, you add enough acid to use up all the buffering capacity. Once this has been done, decreasing the pH is easy. However, it should be noted that the resultant lower-pH water has much less KH buffering than it did before, making it more susceptible to pH swings when (for instance) nitrate levels rise. Warning: It goes without saying that acids are VERY dangerous! Do not use this approach unless you know what you are doing, and you should treat the water BEFORE adding it to the aquarium.
 
Products such as ``pH-Down'' are often based on a phosphoric acid buffer. Phosphoric acid tends to keep the pH at roughly 6.5, depending on how much you use. Unfortunately, use of phosphoric acid has the BIG side effect of raising the phosphate level in your tank, stimulating algae growth. It is difficult to control algae growth in a tank with elevated phosphate levels. The only advantage over hydrochloric acid is that pH will be somewhat better buffered at its lower value.
 
One safe way to lower pH WITHOUT adjusting KH is to bubble CO2 (carbon dioxide) through the tank. The CO2 dissolves in water, and some of it forms carbonic acid. The formation of acid lowers the pH. Of course, in order for this approach to be practical, a steady source of CO2 bubbles (e.g. a CO2 tank) is needed to hold the pH in place. As soon as the CO2 is gone, the pH bounces back to its previous value. The high cost of a CO2 injection system precludes its use as a pH lowering technique in most aquariums (though see the Plant FAQ for inexpensive do-it-yourself alternatives). CO2 injection systems are highly popular in heavily-planted tanks, because the additional CO2 stimulates plant growth.

both above from http/fins.actwin.com/aquariafaq.html

 

[Lunar Jetman]

I've been keeping fish for over 26 years now and this is one thing that I really have never bothered with. I've thought about it, yes but the effort and cost to actually do it and then keep the PH level maintained has always seemed to me to be too high.
 
I've always managed to find fish for the PH levels of where ever I've lived which is generally in hard water areas with a PH similar to yours. In one of my tanks I did have a CO2 system set up to help the plants and that did lower the PH down from 8.2/8 to around 7.6 so that's probably the only way I would consider doing it again.
 
Are you planning to change the substrate anyway though? The only way I've ever done it is to get a second tank (my quarantine tank) and transfer the fish to it, drain the main tank down, remove and replace substrate, refill tank and let the temperature equalise before finally returning the fish to the tank. I've only ever heard of problems for people trying to replace the substrate with the fish in the tank..

 

[Lateral Line]

Dolomite, (a Calcium and Magnesium Carbonate), will resist any changes in a downward direction. It will simply dissolve, releasing carbonate, (and bicarbonate), ions, into the water restoring the hardness and raising the pH again. Replacing the dolomite will be a start, you don't say what other factors there might be. Where I lived, the tapwater was hard and alkaline because it was sourced from chalk, (Calcium Carbonate), boreholes for example.

 

[Bunchbro84]

thanks so much, I am currently trying to figure out what I am going to do. I appreciate the help.

 

[daizeUK]

 My tap water ph I think is 8 or 7.4 I am unsure because one test I did I left it out for like 4 days and one I left out for 1.

 
To test your tap water, leave the water to stand for 24 hours and then test.  This allows CO2 to gas out which otherwise artificially lowers the pH.