Major PH drop. HELP!

[Deliverme314]

MY PH dropped from 6.8 to 5.6 in the middle of the night and my brand new(who was aall ready stressed out) rope fish died. What would cause it to drop so much?

Also my Co2 had brought my ph from 8.2 to 6.8 over four or five days and then my PH controller shut it off but it had been shut off for a day and the ph never rose... stayed steady at 6.8... isnt it supposed to rise again once Co2 shuts off? If it doesnt but my KH and PH leveles are good do I still have an actual reading on my absorbed Co2?

 

[Deliverme314]

just checked my KH and its down to 2... I have no idea what happened here. My Co2 has been shut off for at least a day. I did a 4 gallon water change yesterday... but my tap is hard and alkaline and its only 4 gallons in a 90 gallon tank.

 

[Spy_90]

your PH will not rise when the CO2 is turned off. The plants can't add O2 that easily. You could try some surface agitation, such as an air stone or something. That would help with the CO2 -> O2. 4 gallons in a 90 gallon is nothing, i think that's why your KH is so low. Remember that a low KH is ok, it just means the tank will be more prone to PH swings. In my 10G tank, i mixed 1/2 tap with 1/2 distilled to get a PH of ~7.5 and a KH of around 6deg. My tap is also hard and alkaline. From the tap it is over a PH of 8.6 (highest my test will go) and the KH is about 19*. Just 1/2 and 1/2 braught both levels down to acceptable rates. Good luck! Hope that helped