| Getting the "Perfect pH"
Steve,
I wrote this on another forum and if it is OK with Jim North would like to post it here as well.
REC
An old friend of KoiVet's asked me to write an article for his koi club on pH. He was reading with interest a thread that I was contributing to regarding "the perfect pH", GH, KH and all of those things. And he wanted something less head-spinning than the Mystery Thread. So, I wrote the following and would appreciate any comments on its content and accuracy. Remember this is for a general audiance with no direct way to ask questions.
Getting The Perfect pH For Your Pond.
Much of the talk surrounding koi health issues is about “getting the right pH.” And, in fact, no single water quality parameter is more important than the right pH. The reason is simple… your pond water is your fish’s environment where ALL things happen. Most importantly, the chemistry of the water DIRECTLY affects all aspects of the physiology of the fish, and in particular, the blood chemistry of the fish. So, it is critically important to get the “right pH” or more importantly, the “perfect pH” for your pond. But how?
Let’s start by exploring pH but let’s keep it simple for now. pH defines the intensity of the acidity or alkalinity of the water. Low pH is acid, high pH is alkaline. For koi ponds, the nominal (I did not say “perfect”) pH is 7.5 and the reason is that this is the same pH level of normal blood in koi and goldfish. We also know that the ideal range of pH for koi and goldfish is from 7.0 to 9.0 which simply means that fish will tolerate a fairly broad range of pH levels.
Your pond’s pH level is impacted by a number of factors, including carbon dioxide (CO2) and the buffers available to off-set the CO2. Also, the mineral content of the water (which makes it hard or soft water) plays a critical role. But the most significant is CO2 which is produced as a result of plant and fish respiration, biological bacterial action, and other chemical reactions in the pond. CO2 is very acidic and always present in your pond’s environment. In fact, it is required for the respiration of plants and fish. So, all ponds have an immediate problem that needs to be managed.. the acidic CO2.
Along with the pond’s pH level, we also need to know and understand our carbonate hardness (KH) and general hardness (GH) numbers as each plays a critical role in your pond’s pH level. In short, KH levels show the ability for the water to neutralize the acidic CO2. We call this buffering. And the GH levels provide the hardness of the water usually expressed in how much dissolved calcium and/or magnesium is available in the water. Using the US metrics, the ideal range for both KH and GH levels is 80-120. KH levels can be achieved using baking soda on a regular basis as the constant barrage of CO2 in the water will deplete the buffers over time. How fast depends on what’s in your pond (fish load, plants, water volume). GH levels will remain constant except when diluted by water changes with lower GH levels. Calcium chloride and magnesium sulfate (Epsom salts) are good for maintaining GH levels.
In chemistry terms, the relationship between the pH level, KH levels and GH levels is very complicated. But it is safe to say this…. A good KH level (80-120) will maintain a stable pH AND a good GH level (80-120) is essential for that to happen. Now, this is simplistic but the point is that both good KH and GH levels are required to establish and maintain a rock-solid pH level.
Virtually every koi health practitioner will tell you that when it comes to pH, a stable pH is more important than the nominal 7.5. And this is absolutely correct. Avoiding swings in the pH is critical to maintaining excellent koi health. The proper adjustment of both KH and GH levels will guarantee a stable pH.
But what about reaching the “perfect pH”?? Or is there such a thing? In fact, there is such a thing as a “perfect pH” but it may not be pH 7.5. It may be 7.0 or even 8.8. And the reason is simple: your pond, with all its living parts, is going to be the pH it wants to be based on the chemistry happening inside of it. Our job is to provide our closed-system ponds with the chance to find and hold its own pH level by managing good KH and GH levels. Once we have provided a stable KH and GH chemistry environment, the interactions of the minerals against the buffers, which are neutralizing the acids will allow the pond to find its own stable pH. Once the pH is stable, leave it alone even if it is 7.0 or 9.0 as the fish will adapt and thrive in a stable, stress-free environment as you now have the PERFECT pH.
Here are some additional comments about pH:
1. The pH of baking soda is 8.4 but that does not mean by using it your pond water pH will be 8.4. The overall impact of the minerals (GH) and acids in the water will move your pH to a stable level.
2. Know the pH, KH, and GH of your source water so you understand how this water will affect the pond chemistry during water changes.
3. NEVER… NEVER… NEVER… use products designed to adjust your pH up or down. NEVER. Have I made my point? If your pH needs adjusting, do it through the proper balance of good KH and GH levels. The addition of these products adds acids (for down) or alkalines (for up) will only deplete in short order.
4. If you have a stable pH of the nominal 7.5, consider yourself lucky.
As I said earlier, this is a simplistic view of how the chemistry in your pond can be managed to get your fish the “perfect pH.”
| 
06-12-2006
. I added some buffer to it and it brought it down to 7.98. What should it be at during the hottest part of the day?
Linear Mode
Similar Threads 
