Why does the pH change so much in just one of my tanks??

Question

When testing all the water in my house my 10 gallon, 120 gallon, upstairs and downstairs sinks all have water with a pH of 7.1. Then when I checked my 29 gallon tank it has a pH of 6.4 and it is filled with the upstairs sink. Can anyone tell me why that is? The only thing I can think of is I have 1 one foot piece of driftwood in there but my 120 has several pieces of similar driftwood (it's a little darker then the 29 gallon's) and the pH hasn't changed there at all.

I do a 20% water change almost weekly and that never seems to have an effect on the pH in any tank so far.

Thanks in advance.

I am asking this because I am going to want to move my big angel to the larger tank and that is such a big pH change for him. Don't want to lose him.

Wow lots of really good detailed information so far.. this will be very tough to choose a best answer b/c they are all great! I'll try taking out the driftwood tomorrow and do another 15-20% water change. They both have plants, there are a few more in the 29 percentage wise very few in the 120 so far and not as much driftwood %age wise also. I am not done stocking the 120 either. I have maybe 23 inches of fish in the 29 and maybe 33 inches in the 120. Hope this adds enough additional info. I almost always do water changes at the same times on all three tanks.

Answer 1

Lots of LONG answers! Apparently the source of the problem is in the 29 gallon tank.

First, I agree with low water hardness being a contributor - this buffers the water against pH changes. But the same water is in all the tanks.

Second, you've got driftwood in more than one tank. It may be a larger proportion of the contents of the 29 gallon though, or newer and leaching more organic acids. Try swapping it out with another piece the same size and see if that makes a difference.

Third, how does your stocking compare between the tanks? Fish "respire" and produce CO2. This combines with water to form H2CO3 (carbonic acid). This acid, as you might guess, will lower your pH over time. If your stocking is higher in your 29 gallon, more CO2 will be produced and the pH will go down over time.

Fourth, is the big tank planted and the small one not? Reverse the above statement. Plants pull CO2 out of the water for photosynthesis and raise the pH slightly over time.

These are the causes I can think of off the top of my head right now. If you want to add any info to the question based on these possibilities, I'll check back in a bit.

The differences in your tanks pHs would be a bit of a change for the angel. If you wanted to do move him to the other tank, I'd use a drip acclimation. Put your angel in a clean bucket with a cover and enough water to be able to swim. Run some airline from the big tank to his bucket and put a control valve on the end. Adjust the flow to a few drops a minute. This will add the new water at a slow enough rate that he'll be able to adjust to the change gradually. If the bucket is 1/2 full or more from water from the 29, take half the water out when it's full and run the water to fill it again. If the water from the 29 is 1/4 the bucket, you should only need to run the drip one time.

CAUTION: Don't let the bucket overflow!

Answer 2

Several things can lover pH. Driftwood, which you have, is probably the main reason it is dropping in the smaller tank. You may have several small pieces in the 120 gallon but do you have 4 times more than the 29 gallon? Probably not.

As mentioned, you water probably has very little buffering capacity. Most municipal water supplies are that way to make the water taste better for drinking. As long as the fish in both tanks are happy and healthy, I wouldn't worry about it.

I certainly wouldn't use any of the pH altering chemicals. All they do is put your pH in a constant swing. When it drops and you add it, the pH goes up. It drops back down and you add more. That is very stressful on your fish. Fish can adapt to a pH that isn't optimal for them but they will never adjust to a pH in constant swing.

If you feel you must raise it, the simplest way to adjust your pH upward is to get a very small amount of crushed coral from someone that has a cichlid tank. Put it in your filter. It will slowly raise your pH and keep it there. And it really only takes a little. For you 29 gallon, you probably wouldn't need more than 1/4 to 1/2 teaspoon full. If you do try that, just keep a check on the pH to make sure it doesn't get too high.

As for moving the angel, you can do it without much problem. The evening before you make the move, do a 30% water change. That should raise the pH in the 29 gallon tank from about 6.4 to about 6.6 (about 30%). When you make the move, put enough water from the 29 gallon tank in a bag or container large enough for him to be able to move freely in and put the angel fish in it. Float him in the 120 gallon tank. Every 15 minutes, add a cup of the tank water to the bag with him. If the bag gets full, pour some out into the 120 gallon to make room for more. Do this for 2 to 3 hours. That will gradually raise the pH of the water he is in to the pH of the tank.

I had to do this when I bought my 4 angels 2 years ago. My Q-tank pH was about 7.0 and the water in the bag from the LFS was below 6.0. I spent 3 hours adding water every 12 to 15 minutes and they are all still alive and doing fine. They were about the size of a quarter then and are about 3" now, not counting their tail.

Answer 3

Oxygen has no impact on pH; in basic terms carbon dioxide, it is used to diminish the pH. What have been you applying to get a pH of 6.0 interior the 1st place? in case you're applying buffers then you certainly might desire to continuously save at it or the buffers would be absorbed and the pH will bounce precise back to the place it began out interior the 1st place. you may desire to examine the carbonate hardness (Kh) of the water. delicate water with a pH of 6 might have an particularly low Kh. in case you have a extreme Kh then the two the buffers have been absorbed or Marcus is right and you have something dissolving it is increasing the Kh which in turn will boost the pH.

Answer 4

Your tap water might be low on salts, the buffering kind, after a while the tank goes acidic. The driftwood makes the pH stable although acidic as well. Have your gH and kH tested to see just how soft the water is. You may have to use a buffering product. Changing a fish to more acidic water is more dangerous than changing into alkaline water. Alkalinity and acidity are not the same as hard and soft, they are two different things, that usually go hand in hand. I think you have soft neutral water from the tap. When its used in the tank the fish, bio-media, plants and algae all use up the carbonate in the water releasing a hydrogen atom. As this happens the water becomes more and more acidic over time. You are going to have to go to an aquarium specialty store (because Petco and Petsmart don't carry buffering salts), and ask them what you should use to make the water a little more stable.

Answer 5

It sounds like to me that you have quite low carbonate hardness. This would allow the pH to drop easily and quickly. Of course, lots of things can have a minor impact on pH, including the filtration, the surface disturbance and the fish load, but for any of them to have that much impact in one day your carbonate hardness would have to be quite low. Move the fish using a large bucket. Fill it 1/2 way from the tank and then begin to add water from the new tank. Just a little at first, then larger and larger amounts about every 30 minutes or so until the pH in the bucket is very close to the pH of the tank. That should change it slowly enough not to have a bad impact on the fish.

MM

Answer 6

Driftwood can cause a drop in PH..and in a smaller tank it will have a bigger impact.


Get some Chemi Pure http://www.boydenterprisesonline.com/pages/2/index.htm

Answer 7

my tank did that so much so i have to get spring water when i do a change this might help...it did for me and now a have 6 barbs(3 tigers 3 greens) and 2 cat fish. make sure its SPRING water NOT distilled water!distilled water is bad for your tank

Answer 8

Have you tested the tap water in both your 1st tanks tap and the upstairs tap? Is the gravel in the tank the same? Some gravels in a tank will alter the PH reading. (Only a certain few)

The PH comes from the hardness or softness of your water source. Adding chemicals to treat your tank is only a temporary fix and must be monitored constantly. These are never good ideas.

Here is more on PH and how it works.
The property of water to resist changes in pH is known as buffering capacity. You can determine the capacity of your buffering system by measuring total hardness. A reading of 4-6 dH or higher is usually adequate to keep the buffering system in place and maintain a stable pH. A reading under 4 dH means there isn't enough of a buffering system and the pH is likely to drop. For higher pH levels, you will probably want to aim for 6-12 dH. Many hobbyists choose to measure only Carbonate Hardness (KH), which is a measure of the calcium carbonates in your water. This test is also effective in maintaining a proper buffer system. When testing for Carbonate Hardness, a reading of 75-100 mg/L is adequate for most aquariums, while a reading of 100-200 mg/L would be desired for higher pH levels. For the purpose of freshwater aquariums, measuring either total hardness or carbonate hardness is necessary, but measuring both independently would not be needed.

You need to know that anywhere in your aquarium where detritus (a fancy term for dirt) accumulates is a source of Phosphate production. As detritus accumulates in your gravel bed and on your filter pads, the Phosphate levels in your aquarium rise. Free Phosphate ions may bond with calcareous buffering material, precipitating calcium from your aquarium, and reducing your aquariums ability to keep pH stable. This is why it is so very important to clean your filter pads regularly and vacuum the aquarium gravel with each water change. In addition, your tap water contains buffering ions. Doing regular partial water changes will help to replenish the buffers which have been lost. This is important in all aquariums, because fish respiration and organic wastes alone will cause a gradual drop in the ability of your aquarium to buffer against pH swings.

Now the question becomes what to do if the fish you want to keep have very special pH requirements. If your fish prefer a pH level which is reasonably close to the pH your aquarium water is naturally buffered to, then I do not recommend you make any changes at all. Unless you are keeping an extremely specialized fish your fish will be fine. On the other hand, if your fish have pH requirements which are far from the values in your tank, then you have work to do.

Let us consider methods of raising the pH of your tap water. There are many additives on the market today which claim to raise your pH. Most of the liquid products on the market today are a 50/50 success at best when used alone only to find the ph will soon return to the normal level of 6. You also need to use a product to increase the buffering ability of your aquarium. To maintain a stable pH in the upper levels of the pH scale for fishkeeping, I would recommend using a buffering substrate such as crushed coral. You can add crushed coral to your existing aquarium. You can place larger amounts of shells or chrushed coral beneath the substraight in the tank. I personally place the crushed coral in a mesh bag and place the bag in my filter. You will want about 1 kg of crushed coral per 40 liters of water to buffer the water to hold a pH around 7.6. This method does not allow for the use of large quantities of crushed coral, but can be effective if you only need to make small adjustments to your aquariums buffering ability. This is why ocean items such as shells and ocean sand should not be used in a fresh water aquarium. It does raise the PH level.

Be assured that attempting to control pH is the most frustrating experience for a fish hobbyist. I would guess that 50% of the problems encountered in new aquariums are a result of the aquarist attempting to change the pH level. Few fish keepers actually need to adjust their pH. For the majority of aquarists your tap water pH will be adequate. The dangers of adjusting the pH incorrectly far outweigh any benefit you may receive by moving your pH a few points on the scale.

Remember, when it comes to adjusting your pH, less is more! Stability is most important. Routine maintenance is the key to keeping your pH stable and your fish healthy!

Also, do not use baking soda in your tank. Over doing the ph plus adding additional salt is not going to do your tank any good. It will also revert back to 6 when the carbon filters pull the Soda out.

Hope this helps

As far as moving the fish, I agree with MM here. Adding small amounts over time to your fish's water is the best way to acclimate him to his new home.

Answer 9

no problem put it in a big tank