Ph Aeration And New Planting

[neilc]

Can someone explain how aeration might affect PH, or a recent addition of 2 test plants having affect ?
Added a small sword and grass type to help with Nitrate40 and Phos?? Algea was returning quickly after cleanings.
Tank was old with 3 occupants. Then wife overstocked(??) with 4 neon, 1 redeye, 1 blu tetra
Think we cycled, ich showed up, ich gone now, and lost most fish, now playing catchup and trying to learn quick.
My 10gFW has been 7.5 - 8 and resistant to coming down by water changes, Weekly 10%, tap at 6.6.
Power Wisper filter HoB is injecting bubbles, return water is stirring aeration in, as well as stirring surface.
Could too much salt do this ? as I supplemented the ich meds with a month ago, and possible mini cycle?
First post so take it easy...
10g
1 tetra red eye, 1 neon tetra, 1 blue tetra,
78*
PH 7.8
KH 8
Gh3
NH3/4 0
No2 <0.3
NO3 10 - 20
Tap
PH 6.6
KH 0
Gh 2
NH3/4 0
No2 <0.3
NO3 not tested

 

[neilc]

No Help ??

 

[Glod]

Ahh, so you want to know what is raising the PH in your tank from the ph of your tap water ?

Salt could have an effect if you add too much. It could also be caused by decor in the tank. What do you have in the way of rocks, gravel etc ? When you added salt did you add it again with water changes ? How much salt did you add ?

Plants will not affect the PH to any degree so that isn't the problem. Adding 2 plants isn't going to make any noticable difference in your nitrates, but it may make your fish feel more secure and happy. It takes a lot of plants to make any dent in the chemistry of a tank.

 

[Bignose]

First thing is to take a sample of the tap water and let it sit out 24 hours and then test that. Oftentimes, water companies dissolve CO2 in their water to minimize sedimentation of minerals in the water. It also helps minimize some of the corrosion of pipes. Sitting the tap water out, allows the CO2 to diffuse out and reach equilibrium with regular air.

To wit, my tap water has always tests at a pH around 7.2 to 7.4, but if you let it sit out overnight, it is 8.2 to 8.4, which is exactly what my tank is.

If the 24-hour aged tap water is still testing significantly lower than the pH in the tank, then start to look for something in the tank, rocks, gravel, some decorations.

 

[neilc]

I do have my tap posted in the original.
This is aged water, I set 2 gallons out for the next weeks change, at the time of WC.
I am really thinking I may be over aerating.
(Airpump and HOB)
But can't seem to ponder the Aeration affecting PH, this is what I'm really asking.
thanx,
neil

 

[thegnu]

hi,
too much aeration can drive off carbon dioxide (co2) and this will cause a rise in ph. some gravel is calcareous and can leach raising ph. also rocks. a good way to know which rocks are safe is, hard rocks = low ph. soft rocks = high ph

 

[Bignose]

Here is how you can tell if it is aeration: Take your tap water, and put it in the bucket and toss an airstone in the bucket. Test that water.

Aertion cannot increases pH by itself. Aeration can drive off CO2, but the OP does not say that he is injecting CO2. Unless the tank is very, very, very heavily planted, the CO2 levels in the tank are not going to be very different from equilibrium.

That is what aeration does. It brings the water and atmosphere towards equilibrium faster. That is, the water will only dissolver certain amounts of gases, based on the temperature and pressure and composition of the air. Just by putting in extra air, via airstones, cannot change what the water can dissovle. What it will do is achieve the equilibrum state faster.

This is why airstone can drive off CO2. If you inject CO2, there is more CO2 in your water than would normally be in there from the atmosphere. Because there is more CO2 than the equilbrium point, by putting in an airstone that allows equilibrium to be reached faster, the CO2 leaves faster than it normally would. One way to slow the speed at which equilibrum is reached? To minimize surface distrurbances -- which is what the typical fishkeeper who injects CO2 strives to do.

The air-water system will always, always, always tend toward equilibrium. The laws of thermodyamics are very clear about that. However, we can change the rate at which the system tends toward equilibrium.

So, back to the original question: Please perform the airstone in a bucket test and post that result.

If that pH is still low, then you need to start looking at your gravel, decorations, etc. Something there could be raising the pH.

re: thegnu: hard rocks & soft rocks? That may be true in general, but there have to hundred is not thousand of exceptioons to that rule. What determines if the rock raises pH is what the rock is made of, and water from the rock dissolves into the water. The best way at home is to use the acid test. Put an acid on the rock, and if the rock is basic (pH rasing), the acid-base reaction will almost always have a gaseous result. This will be seen as bubbles or fizzling where the acid contacted the basic rock. Vinegar is often recommend as a good household acid, but acetic acid is pretty weak, and vinegar is usually pretty dilute. The best one really is the second bottle of the two-bottle nitrate test. That second bottle is concnetrated nitric acid. So, if the airstone in the bucket test doesn't yield the pH increase, start testing your gravel and/or decorations.