Water conditions changing quickly

[joshg]

Hi All,

I've got two betta fish in seperate tanks. As one of my fish got sick recently i'm being very proactive when it comes to checking their water. I changed their water the other day and applied water conditioner at the likes and did a pH test, all normal. I checked the pH the next day and the water had was a bit acidic. Is it normal for water to change that quick? The tanks hold 12 litres (3.1 gal) and 8 litres (approx 2 gal) of water. I've recently put 2 small corner carbon/floss filters each tank running on a single 50 cycle pump.

Both fish sit on a bench near a window and get a bit of sunlight during the day, though not direct.

Is this normal or could there be something wrong with my setup?

Cheers

 

[Bignose]

The nitrifying cycle will acidify the water. Usually, the buffering capability of the water does not allow large swings in pH. In addition to your tests for ammonia, nitrite, and nitrate, if you got a test for KH it will directly tell you what the buffering capability of your water is. A test for GH will indirectly tell you if you cannot find a KH test, but it is only a guess, KH is exact. My guess is that you have very low buffered water, so you may have to supplement it with some baking soda or other to help keep the pH more stable.

If you are unfamiliar with what cycling or the nitrogen cycle is, or what KH/GH is, there are seveal posts (like the pinned what is in your water post) and many many webistes that explain cycling -- type "cycling aquarium" into Google.

 

[freddyk]

It's also not uncommon for the ph to change once it is cycled through the aquarium equipment for a while. The same thing would happen if you filled a bucket with water and ran an airstone overnight. Usually the ph will rise a bit, but sometimes it will lower. Once the ph dips, does it remain stable or keep dropping?

 

[Ed4567]

I would take a guess at either:
-Ammonia being converted to nitrite to nitrate in the filter- NH3 (NH4+) is being converted to NO2 then to NO3. If my chemistry is correct I think this results in H+ ions being released and a lower pH.
-If you have plants in the tank, then photosynthesis results in an increased pH (due to taking up CO2 which is disolved in the water as carbonic acid) so if you tested in the evening you would get a higher reading than in the morning.
-Your source water could have a lower pH than the water in your aquarium.
-Your test kit could be wrong- they are known to often be inaccurate.

Any of the above (except for the last one) would be compounded by a low buffering capacity in your water.
Ed

 

[joshg]

Hi All,
I tested the, Ammonia, Nitrites and pH last night. The pH is still slightly acidic but hasn't changed as dramatically as it did previously. The nitrite test was 0 but the ammonia test was approx 0.3.

I'll go down to the pet store today and get a kH kit. I'm looking on getting a much larger tank (3 or 4 food) in a few months so i just want to make sure i get all this right. I hear it is easier to look after a big tank than a small. is that true?

Thanks for all your help

 

[isu_guy]

Yes- larger tanks are easier to care for in general.

They are harder on the pocketbook and are more time consuming for things like water changes.
But the larger the tank, the more options you can have for fish.