Jay

I think that in our hobby pH is a very misunderstood measurement especially by beginners. It leaves them vulnerable to being sold "Snake oils" to solve their "pH problems" and frustrated and mislead as aquarists. I am not saying pH is not important, but taken out of context it can be daunting.

Myths and Misinformation have gone on for years... for example; and stated within the bounds of common sense here are a few of the majors...

Rapid Changes in pH kill fish.
You must at all cost maintain a neutral 7 pH.
Fluctuations in pH stress fish and leave them vulnerable to disease.

I inject CO2 into my tank during the lights on period. My pH drops from 7.2 to 6.2 in less than an hour, and reverses at lights out. My fish are fine

You do not need to be a chemist to understand pH, but requires looking into if you are going to be a sucussful hobbyist.

regards,
Jay

LadyViper

I hadn't heard that before, about the CO2. How often do you add that to the water? Is it a daily thing, or less often?

Jay

Hi Lady,

CO2 injection is common in a high-tech heavily planted aquarium. Plants are 60% carbon and their carbon source in nature is CO2. Remember studying photosynthesis in high school Regular tank water dissolves about 3 - 5 parts per million of CO2 out of the atmosphere. To get rich, lush, healthy plant growth it needs to go to 30 - 40 parts per million thus the CO2 injection. The CO2 bubbles in all day while the lights are on and is turned off at night. Because the CO2 causes carbonic acid to be formed the pH drops.

I used that as an example to debunk the myth that rapid pH changes kill fish,
when we all should know it is rapid change in osmolality that kills fish.

Regards,
Jay

LadyViper

I completely understand the plant/co2 topic, but what if you don't have a planted tank? Would it only be recommended for a tank with tons greenery? To be honest, I am unable to get a plant to thrive in my tank. The problem being a couple of things; fairly new to the keeping my own tank game and lighting. I am just using the standard lighting that came with the aquarium, and I know that is not proper lighting for any plant life. Keep talking, I have a lifetime to learn about this...lol

Fish Head

Im using standard lighting but add some special aquatic plant fertiliser once a week. The plants are thriving, getting alot of new growth.
Most of my plants have roots, I assume that would help prolong their life..

Jay

It shows that they are investing growth and energy in nutrient uptake methods.

Jay

Fish Head

Back on the Subject of PH..
After testing, I find my PH needs to be lowered each week. What factors could make PH rise in a freshwater tank?
To test Im using an Aquarium Pharmaceuticals Test kit and using the PH Down solution in the kit to lower. I typically get water close to neutral but find its back up at 7.6 a week later.

Jay

One of the persistent myths of the aquarium hobby is that the pH has to be neutral at 7. I know the myth is responsible for a lot of pH up and pH down chemical sales

Most experienced hobbyists (there are some exceptions) do not worry about artificially maintaining their pH they keep the pH of their tap water. A pH of 7.6 is not high and is just fine no problems.

Remember it is not shifts in pH which stress fish it is elevated levels of DOC (dissolved organic content). The chemistry of the tank water is constantly changing during the week as fish waste and excretions, bacterial breakdown of leftover food, etc. etc. are dissolved into the water. pH changes happen, no big deal.

It should begin to be obvious why weekly water changes are important in a non planted tank. The hobbyist wants to maintain a consistent and low level of DOC not pH. and water changes accomplish this not more chemicals!

Jay

LadyViper

OK, I am def starting to understand why water changes are so important. I feel like such a butt for only doing once a month prior to talking with all of you. No wonder why my Ph doesn't stay neutral, hmmm so much to learn. It's amazing my poor fish have made it this long...

ahill3780

pH stands for "Potential Hydrogen" and is at its most basic, the measurement of Hydrogen ions in a given environment. In our hobby we use this measurement, along with the measurement of Alkalinity to give us an idea of the overall stability of the environment more so than for knowing how many hydrogen ions are present.

Alkalinity can be a different type of measurement in and of itself from one environment to the next. I know that in seawater, Alkalinity is the measerement of how much acid (H+) is needed to bring the pH down to 4.5 where all bicarbonate is converted into carbonic acid: for all you chemist's out there the process is as follows: HCO3- + H+ -> H2CO3 (Don't ask me to explain - I am not a chemist and I understand this just as much as you do!) But in its most basic form Alkalinity is the measurement of how acidic a body of water is.

Alkalinity directly effects pH and in order to get a proper measurement of pH you must know what the Alkalinity in a certain solution is also. If you test your pH weekly and it is constant then you have established a good balance between pH and Alkalinity and you are off to an excellent start.

There are several factors that can effect the pH in a solution such as the presence and level of sunlight, the addition of CO2 as well as certain metals, temperature, and so on, but the main focus when it comes to pH in an aquarium should not be whether or not you are hitting a certain mark but rather how consistant and stable it is within a specific range. This is why you will hear most people say that you should "try to keep your pH between 6.8 - 7.1" instead of "keep it at 7.0" - because there are so many different factors that can effect it one way or another, and each and every organism has its particular preference which can vary widely between one and another. It is not that an organism needs to be kept at that range, it is just that it thrives better at that range. Now if you raise or lower the pH too greatly (6.0, or 7.6 for example) then there are negative impacts on the organisms in the form of health problems which is why we try to keep it around the nuetral mark of 7.0 which has been found to be an acceptable range for most organisms that will be found in the aquarium trade.

If you are having a hard time keeping your pH in balance it is likely due to a difficiency in Alkalinity (acidity) and/or Hardness (DKH) and you should test for both these levels and adjust as needed.

Remember when testing that you should always test the water under the same conditions each time so that you can guarantee that the results are comparative to one another. Meaning that if you test the water with the lights on at 78 degrees the first time, then the nest test should done with the lights on around the same temp so that you can accurately tell if there is a difference in the two readings.

pH drops at nighttime because Alkalinity rises. This is due to several reasons that I won't go into at this time, but I only mention it as a further reason to test your water under similar conditions.

Which reminds me, Jay,

If you want to keep your pH more stable in your planted aquarium without having to turn off the CO2 system each night then you might consider installing a sump or refugium and lighting that when the lights go off in the main tank. This way your fish and plants can "sleep" while the lights in other tank (nicely hidden away from the main tank) keep the Alk levels in check, which in turn will maintain a more stable pH throughout the night. This is a wide practice in reef tanks where some organisms demand a more constant pH, and it is very successful.

I think thats enough info for the moment, I will let you all digest that and answer any questions you have afterwards.

Cheers!

__________________
"The only thing that happens fast in saltwater tanks is failure."

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