High pH: Too Much Aeration?

[dartos]

I have been having a problem with getting the pH of our 10 G tank down. I have been using pH down from an aquarium pharmaceuticals pH test kit for several days. I took my water to my lfs (master test kit is in the mail) and they told me that my pH was too high to get fish (8.4). They then test the hardness and said that that was what my problem was (didn't give me the numbers), and I didn't doubt them because our water is known to be somewhat hard for city water.

They sold us Blackwater Extract to soften the water. I went home and immediately used it and after two days of using both it and the pH down, I still can't get it below 8.4. I tested the tap and it is around 7.4.

I read on these forums that too much aeration will push CO2 out and cause a rise in pH. I have an Aqua Clear 20 (which is rated for a 20 G tank, but too much filtering is not a problem right?). Along with this I asked at my local PETsMART if I still needed an air pump and they said yes. So I bought a pump, tubing, and a stone.

Now I have bubbles all around the top of the tank. I have joked around with my wife that we are going to need to buy amphibians rather than fish. It never occured to me that the O2 was the problem (glad that minor in chemistry paid off )

I apologize for such a long post, but my final question to all of you is whether you think that our water hardness is the actual problem or whether it is more likely the aeration, and do we need to get rid of the pump or regulate its output? Thank you for all help in advance.

 

[Paul_MTS]

sounds like your airating too much. as long as your filtration gives good surface disturbance then thats all you need, i'ved never used air pumps.

it is true that too much O2 will push your CO2 out causing your PH to rise as this is what happens to me due to my type of filtration.

MJy tap is 7.4 but my tank is way up at 8.3.

You can fish without any probems, I have quite sensitive fish but aslong as you adjust newly bought fish to your PH then you will be fine.

Trying try removing the air stone and see what happens.

 

[rdd1952]

As a general rule, driftwood will lower your pH. I love driftwood but my pH only runs about 6.6 so I can't use it. You could probably fit a small piece in a 10g

 

[Paul_MTS]

bogwood only alters PH in a very small way and only does it for a short ammount of time. If you soak your wood before using to get the tannins out I doubt you will see any drop in PH.

I have several large pieces never soaked and never affected my PH.

 

[dartos]

Thank you both for the quick and informative responses. I will try removing the air stone tonight when I get home. Thanks again.

 

[Bignose]

I would just like to add that a pH of 8.4 is hardly prohibitive for keeping fish. Some sensitive fish are going to be unhappy, but more commericial bred fish have become used to the harder waters than thier native waters. For example, the neon tetra from the soft Amazonian basis have been successfully bred in Florida's hard alkaline water -- and consequently neons are hardly considered a sensitive fish anymore. Their cousins, the cardinals are still largely wild-caught and are much more sensitive to hard alkaline water.

I live in IN also (though not sure how close Lafayette is the Dumbest City in America ) and you want to ask your LFS if the fish are being kept in local water (not RO or distilled water) and if the fish in the store have acclimated to the local water they should be fine in your tap water as well.

To wit, my tank is 8.2 to 8.4 in local tap water, but many of my fish have spawned -- generally a good indication they are pretty happy. I have caught the tiger barbs, the lemon tetras and the aeneus cory cats all spwning at one time or another. I also keep scissortail rasboras, mollies, sergeant major loaches, and an opaline gourami and they have not shown any ill effects from the water as near as I can tell.

So, 1) acclimated (generally commercially bred) fish should be fine in a pH of 8.4, and 2) the cichlids from the rift lakes crave a pH in the 8.0 to 9.0 range -- more than perfect for your water. Most livebearers thrive in water like ours, too. So, there are plenty of options.

 

[steelhealr]

Hi..I just want to add an opinion that I think your pH is mostly from the hardness of your water. I went to school not for from you and the water IS harder out there. Although bubbling an airstone can cause improved water circulation and off gassing of CO2, remember that you are bubbling AIR through the hose NOT oxygen and there is some Co2 going back in from the air. After you get your Master Kit, you may want to invest in a kH/gH kit and see what your carbonate hardness is. If your kH is really high along with your hardness (gH), I doubt the airstone is the cause of your problems. Also, I agree with one of the posts above that an elevated pH is not necessarily going to hurt your fish. Find out what the parameters are at your lfs. If his pH is 7.0 and yours is 8.4, those fish are going to go belly up unless there is a slow acclimatizaton. Remember that there is a 100 times hydrogen ion difference for each 0.1 change in pH...HUGE. If you are having loss of fish and your water IS higher than the lfs, you may be one of the people who may have to use peat or a water softening pillow, but, I wouldn't do any changes until you've researched this out Good luck. SH

PS...What kind of substrate is in the tank (gravel?)Any shells or rocks?do you test your tap water right out of the tap or let it sit a bit? Sometimes when the water is under a lot of pressure there is some dissoved gases in it. Try shaking the water a bit in the tube, let it stand a bit, then recheck the pH and see if it changes at all.

 

[Bignose]

Remember that there is a 100 times hydrogen ion difference for each 0.1 change in pH...HUGE

While the change in hydrogen ion concentration is not linear/proportional with pH, it is not this extreme.

100 times hydrogen ion concentration would be a change in 2.0 pH units, not 0.1

From the definition of pH:

pH = negative of the log base 10 of the hydroen ion concentration = -log_10[C(H+)]

example:

if the hydrogen ion concentration is 10^-7 = 0.000 000 1,
the pH = 7.0

if you change that 100 times:
100*10^-7 = 10^-5 ... pH = 5.0

on the other hand, if pH is 7.1 (a change on 0.1 pH units) the concentration is:
10^-7.1 = 7.943*10^-8 = 0.000 000 079 43

Clearly not a proportional/linear change, but not quite as extreme as steelhealr makes it out to be.

 

[Bignose]

Oh, let me add that here in lafayette, the KH=12 or 13 dH, and the GH = 22 or 23 dH, both very high. The water out of the tap is 7.2-7.4 ish, but the compressed CO2 in the tap artificially lowers it. As I said above, the tank pH is 8.2 to 8.4. I do aerate my tanks, but not for the pH change (which as steelhealr said is most likely negligible) but for the currents the bubbles develop in the water so that there are less dead spots in the tanks.

 

[steelhealr]

Good post Bignose. SH