Hello everybody, I just wanted to ask if anyone might have an idea why my Ph would decrease from from 7.4 to lower then my PH tester goes, which is 6.2. Im assuming it might have something to do with getting a new filter because the day after i replaced my old filter with my new filter the PH changed. The only other change i made to my tank was getting some plants. Also my tank has been cycling for about month and a half now if that helps :S

Thanks

*ouch* Not good! Really, you should have left the old filter going while the new "cycles" in to help jumpstart the new one. Sounds like a ph crash too! Are there fish in the tank? How often to you change water & clean?

Do you test for kh & gh?

Hi, you really need the help of some of those techoheads like Dataguru, Toothless, Captk (to name a few) but I'll have a guess.

pH can drop suddenly if the buffer in your water is all used up. Buffer is the dissolved minerals that harden your water and make it alkaline. NitrItes and NitrAtes will absorb (for want of a better word) your buffer and if it is all used up - crash goes your pH.

Since your tank is fairly new I don't think nitrAtes would be excessive. When you changed your filter you could have upset the biobugs and the cycle of your tank causing a surge in nitrItes and possibly ammonia too. This could be the cause of your pH crash.

First thing I suggest is a 30% water change, to gradually increase your pH back up. I would do 30% for 3 days in a row.

Do you have test kits for ammonia and nitrItes? When you do the first water change also add enough water conditioner to treat the whole of the tank water volume - I hope the brand you have neutralises ammonia/nitrIte.

Watch you fish carefully - sudden changes in pH are dangerous and also can bring on stress and other illness.

I have read that changes in ph upwards are not as stressful as changes downwards

Its actually pretty wierd :S I just did water change and added ph buffer to increase my ph...I tested the water b4 and it was a light yellow then i added the ph increaser and it just turned to a dark yellow, its wierd because yellow isnt even on my color chart(esp. dark yellow).
I have a wardly Junior ph water test kit, which uses shades of green to blue and the chemicals i add are amquel plus, novaqua, cycle(bacteria), and plant grow.

Are you useing a liquid like the ph up they give with the ph tests? Unstable stuff that!

Do the partials as suggested. To increase the ph & kh consequently, 1/4 tsp of baking Soda per 10 gl's will raise it 1 dh. This should be done gradually over several day's until you get the ph up in the range you want to see it, about 7.5 ph or so up. Or around 100-150 ppm up on the kh.

The baking soda will also provide proper buffering and keep it more stable!

Touch, you can still shock the fish's system raising things too quickly, it must be done gradually! They still need time to adjust!

Actually im using a powder form called "Kent PH stable". I have 5 fish in my aquarium they dont really seem stressed out at all so im guessing its not actually a PH decrease anymore. Also the more buffer I add the more yellow the test kit shows(Dark yellow now), but like I said b4 my test kit goes from light green to blue. I think it might be something that I did that might be affecting the test kit not the actual ph kit? maybe im not sure.
any ideas?

Maybe you should get another test kit? Try Aquarium Pharmaceuticals.

How old is the kit then? It could be outdated and just needs replaced!