drobbyb
Bowhead
With all the posts lately about pH crashes and low pH problems, ~~waterdrop~~ and I have written this article to help newcomers with what options may be available for them. So without further ado, here it is!
Tap water can vary in pH and hardness, and all tap water is not equal. Some people are blessed with tap water that is perfect for keeping fish, and some are not. In my case, my water comes out of the tap with a pH of 6.8 and a GH and KH of less than 1. This results in a wildly swinging pH, and if left uncontrolled, can be dangerous to my fish and other inhabitants. If the pH crashes (drops to 6.2 or below) the nitrifying bacteria may be shocked, temporarily stopping their processing altogether but then slowly resuming the processing at a much lower rate.
This will leave you with a buildup of ammonia and/or nitrite. As we all know, ammonia and nitrite(NO2) are toxic to fish, and this situation demands immediate attention. Raising KH (Carbonate Hardness) is a way to resist rapid changes to pH. This is referred to as "buffering" the water. The minerals that buffer (carbonate and bicarbonate ions) can be used up as the bacteria produce more nitrate(NO3) and the acid that goes with it.
Thankfully, there are a few things we can do to prevent this. Adding baking soda to the water can raise your KH and in turn increase your pH. At first glance this seems like it would be the answer, and during fishless cycling it is a good thing, but if you have fish in the tank this can be problematic. Baking soda raises the KH and pH very very fast. Too quick of a change in hardness can harm your fish, and you only want to raise their pH and hardness in small increments over the course of several days or a week depending on how much you want to change it. Baking soda also leaves Sodium in the water, which is less desirable than the Calcium left behind by crushed coral. So baking soda is our method of choice for fishless cycling, but not for fish-in situations.
Commercial products like pH up will also raise your pH, but they do nothing to buffer the water and therefore are a temporary fix. They change the pH too rapidly just like baking soda.
Crushed coral (or aragonite or crushed seashells) will do the same thing, but at a rate that is predictable and slow enough as to not hurt your fish. Crushed coral in an acidic environment will slowly dissolve and release calcium carbonate (CaCO3) into the water column buffering your water. Our method of choice with fish, crushed coral is placed in mesh bags (so it could be easily separated if you change your mind) and placed in the filter (flowing water is needed for it to dissolve significantly.) This sounds great and all, but there is one problem. Adding crushed coral will over time raise your pH, but that's not what we are aiming for. Our ultimate goal is to prevent a pH crash. If you go too long between waterchanges, you risk harming your inhabitants when you do a waterchange. There is a delicate balance between time and waterchange frequency. In my case, I can go exactly 7 days between waterchanges. Beyond 7 days, my water change might shock the fish with too much change in hardness.
To maintain this system and avoid a hardness shock to the fish you need to keep your pH close to your tap water, thus large waterchanges (50%) are in order. You will need to test frequently to find your balance. Work on getting a feel for how many days it takes to reach a 0.5 pH change. This is the balance point and indicates how long you can go between water changes.
Once you get past the serious decision of whether to alter your tap water at all, the actual use of crushed coral is not hard. Bags labeled crushed coral at your local aquarium shop are usually a mix of broken pieces of coral and shell (or aragonite) (also known as marine substrate.) Buy a mesh bag or use a thin sock foot or nylon to hold the crushed coral. Start with a small handful that’s been rinsed and place it in your filter. You can also hang it out in the filter flow in the tank but this will be significantly less effective. During filter cleans, the crushed coral needs to be cleaned of debris. The more white the crushed coral is, the better it will dissolve. This method is also all natural, and lasts for years.
So you can see, making permanent changes to solve low pH problems takes dedication and should not be attempted unless you are sure that you can change the water when it is time. If for some reason you miss a waterchange, you should perform a series of small waterchanges to get the pH and hardness back low enough. This process should take place over a few days.
In conclusion, pH, KH (as well as GH) and water changes play an important role in creating a stable fishkeeping environment. Understanding both the benefits and limitations of the use of crushed coral and baking soda is a useful skill for many aquarists.
A very special thank you to ~~waterdrop~~ who wrote this article with me! You were a huge help and this article wouldn't have been the same without you!
My pH Keeps Dropping, What Can I Do Now?
Tap water can vary in pH and hardness, and all tap water is not equal. Some people are blessed with tap water that is perfect for keeping fish, and some are not. In my case, my water comes out of the tap with a pH of 6.8 and a GH and KH of less than 1. This results in a wildly swinging pH, and if left uncontrolled, can be dangerous to my fish and other inhabitants. If the pH crashes (drops to 6.2 or below) the nitrifying bacteria may be shocked, temporarily stopping their processing altogether but then slowly resuming the processing at a much lower rate.
This will leave you with a buildup of ammonia and/or nitrite. As we all know, ammonia and nitrite(NO2) are toxic to fish, and this situation demands immediate attention. Raising KH (Carbonate Hardness) is a way to resist rapid changes to pH. This is referred to as "buffering" the water. The minerals that buffer (carbonate and bicarbonate ions) can be used up as the bacteria produce more nitrate(NO3) and the acid that goes with it.
Thankfully, there are a few things we can do to prevent this. Adding baking soda to the water can raise your KH and in turn increase your pH. At first glance this seems like it would be the answer, and during fishless cycling it is a good thing, but if you have fish in the tank this can be problematic. Baking soda raises the KH and pH very very fast. Too quick of a change in hardness can harm your fish, and you only want to raise their pH and hardness in small increments over the course of several days or a week depending on how much you want to change it. Baking soda also leaves Sodium in the water, which is less desirable than the Calcium left behind by crushed coral. So baking soda is our method of choice for fishless cycling, but not for fish-in situations.
Commercial products like pH up will also raise your pH, but they do nothing to buffer the water and therefore are a temporary fix. They change the pH too rapidly just like baking soda.
Crushed coral (or aragonite or crushed seashells) will do the same thing, but at a rate that is predictable and slow enough as to not hurt your fish. Crushed coral in an acidic environment will slowly dissolve and release calcium carbonate (CaCO3) into the water column buffering your water. Our method of choice with fish, crushed coral is placed in mesh bags (so it could be easily separated if you change your mind) and placed in the filter (flowing water is needed for it to dissolve significantly.) This sounds great and all, but there is one problem. Adding crushed coral will over time raise your pH, but that's not what we are aiming for. Our ultimate goal is to prevent a pH crash. If you go too long between waterchanges, you risk harming your inhabitants when you do a waterchange. There is a delicate balance between time and waterchange frequency. In my case, I can go exactly 7 days between waterchanges. Beyond 7 days, my water change might shock the fish with too much change in hardness.
To maintain this system and avoid a hardness shock to the fish you need to keep your pH close to your tap water, thus large waterchanges (50%) are in order. You will need to test frequently to find your balance. Work on getting a feel for how many days it takes to reach a 0.5 pH change. This is the balance point and indicates how long you can go between water changes.
Once you get past the serious decision of whether to alter your tap water at all, the actual use of crushed coral is not hard. Bags labeled crushed coral at your local aquarium shop are usually a mix of broken pieces of coral and shell (or aragonite) (also known as marine substrate.) Buy a mesh bag or use a thin sock foot or nylon to hold the crushed coral. Start with a small handful that’s been rinsed and place it in your filter. You can also hang it out in the filter flow in the tank but this will be significantly less effective. During filter cleans, the crushed coral needs to be cleaned of debris. The more white the crushed coral is, the better it will dissolve. This method is also all natural, and lasts for years.
So you can see, making permanent changes to solve low pH problems takes dedication and should not be attempted unless you are sure that you can change the water when it is time. If for some reason you miss a waterchange, you should perform a series of small waterchanges to get the pH and hardness back low enough. This process should take place over a few days.
In conclusion, pH, KH (as well as GH) and water changes play an important role in creating a stable fishkeeping environment. Understanding both the benefits and limitations of the use of crushed coral and baking soda is a useful skill for many aquarists.
A very special thank you to ~~waterdrop~~ who wrote this article with me! You were a huge help and this article wouldn't have been the same without you!
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