pH value in the Aquarium - a Mystery?, Not Really!

by Bronze Ickes

The other day I was in a pet store and overheard a conversation between a clerk and a customer. Their conversation brought something to my attention that I felt needed further discussion and examination. I felt that it might be helpful to share this information so that beginning aquarium hobbyists could avoid some common, but potentially tragic disasters. I only hope that this information gets into the hands of those who need it most.

The customer explained that she had added something (?) to her tank to lower the pH value. But now, the pH value had become far to low and she wanted advice on how to reverse this trend, thus pushing the value back up. The clerk proceeded to tell her about how she could add baking soda to her water and this would increase the pH value. While this is true, baking soda would do just that, I think the customer's problem was more serious than it sounds.

My first advice is to the clerk, whenever a customer has this kind of situation, it is reasonable to ask them more questions, to make sure that you have all the relevant facts and maybe some important details that the customer may hesitate to share voluntarily. For example:

• What product did she add to her tank anyway?
• What is the current pH value?
• What kind of fish live in this tank?
• What was her reason for adjusting the pH value to begin with?

Only then can one recommend a plan of action.

The second advice is for the aquarist faced with problems that involve water chemistry.

First, before trying anymore chemical approaches, always try several small water changes over the next few days. For example, consider changing 5-10% of the water every other day for a week or two. Continue testing the pH value at every step of the way, you may find the problem goes away all by itself. If it doesn't then further action may in fact be necessary, and it is worth taking some time to think it through. Here are some important questions one should ask themselves before proceeding.

What is pH and why should I be concerned about it?

If you don't understand what pH value is, then you should educate yourself about the concept before attempting any adjustments. Do a little research. You will find that it really is not the "mind-baffling" concept many people believe it is.

What causes pH values to fluctuate?

An low pH value is most often caused by a high level of organic matter in the tank. This is chiefly caused by overfeeding, and/or decaying plant matter. A high pH value can often be the result of using ornaments or materials and even some rocks that are not intended for fresh water aquarium use. Many beginners try to put real sea shells or real corals into a freshwater tank which can cause many problems as the calcium decays.

What is the pH value I wish to obtain?

You must learn about your tank's inhabitants and find out what the optimum pH value is for your particular fish. As you study further you will quickly find out that fish have many, many different preferences of pH value. However, there are some general rules of thumb that will help a little.

In general, live bearing fish like mollies, guppies, swords, platys as well as most African cichlids prefer harder alkaline water. On the other hand most egg layers especially those from South America prefer softer acidic water. While this rule does not apply to every species of fish it can be a helpful way to think about your aquarium fish.

What should you do if you have both of these two general types of fish in your tank?

In my opinion, you really have only two options, you can separate the fish into two tanks and attempt to provide the pH value that each group prefers most, or you can shoot for the middle ground, a neutral pH value of around 7.0. As a rule most any aquarium fish can adapt itself to a wide range in the pH scale. What they cannot and do not tolerate is large, frequent fluctuations in the pH value. In the store example above, running home and promptly putting baking soda into that tank was a recipe for cloudy water and serious fish stress. For most community aquariums that contain a variety of fish a neutral pH value is probably the best choice.

What is the long term goal for this pH adjustment?

Everyone should have a goal in mind when they decide that a pH adjustment is necessary. The biggest and most common reason is for breeding purposes. If you really want to induce a certain species to spawn then it is often advantageous and many times necessary to provide the prefect water conditions. The idea is that the best conditions are those that most closely duplicate the fishes natural habitat. You can't get away from research. If you choose this path it is absolutely necessary that you read and learn as much as possible about the fish's native home. For example, if you are planning to breed Amazonan fish then you really should read and study about the tropical rain forest and learn all you can about the water chemistry of the Amazon river. This includes its various conditions during the year from flood time to drought. Only then will you have the understanding of what your goal for pH value should be.

If you are a hobbyist whose main goal is to have a happy, healthy, beautiful community aquarium, the best thing you can do is provide a routine schedule of partial water changes. About every other week will do the trick. If you do this on a regular schedule the pH value will most likely take care of itself and remain essentially stable. As always there are exceptions to every piece of advice but this article is written with the assumption that you are using Juneau's city water as your source. Good Luck, but honestly a good book and a commitment to maintenance is all that is required.