Why/how would PH rise so fast in my tank?!

[netwireless]

I have had my tank for a while (more than a year). I have been doing partial water changes with no problems. I did a fairly major clean-up and replaced around 90% of the water but made sure the water did not go through a full recycle period. However, when I measured the PH in a week, it was at least 3 to 4 degrees higher than the tap water where I live (Calif.). So far I've lost 3 of my fish and testing the water has not shown ANY other problems other than PH being too high! What can rise the PH value so quickly? How can I prevent it from continuing to increase this fast and try and stabilize it? I have thought about gradual water replacement (5 gal a day). Is that going to help, or is it going to make things worst for my fish -- being that it will change the PH too quickly? The PH is now way too high for my fresh water fish.

 

[Bubble_B0y]

do u have any shells or crushed coral??

they buffer the pH of the water.
they automatically dissolve and release calcium/carbonates when the pH gets too low.

 

[greenmaji]

Have you tested the pH of your tapwater after it has set out overnight?
What are the actual numbers your dealing with?

 

[netwireless]

The current PH is in excess of 8.5. I have not checked the PH of the tap water after letting it sit overnight. I did not know that the PH can increase by itself overtime. I will check that by tomorrow. I do have a few shells and even fewer crushed corals in the tank, but not nearly enough to make a difference on PH in a 55 gal tank. Here in California the water is usually fairly hard, and my fear has always been that adding more shells and corals may drop the PH too low. Now it seems things are working exactly in the opposite direction!

 

[greenmaji]

pH is affected by disolved CO2 acids.. Tapwater has disolved CO2 in it.. you said that it has come up 3 points? as in it was 4.4-5.5 before? or did it come up .3-.4 points.. a ph of 8.5 shouldnt kill fish.. a ph of 4.4 will kill the bacteria that consumes ammonia wich will kill the fish bi-proxy.

 

[netwireless]

I measured the PH of the tap water at around 6.5, and since then the PH of the tank has increased to more than 8.5 (closer to 8.7 now). I agree, a PH of 8.5 should not kill the fish, but rapidly increasing PH can negatively affect the fish health and I am looking for a way to find-out what is causing the rapid increase so I can at stabilize the PH, even if the resulting stabilized PH is at 8.5.

 

[greenmaji]

rapid change of any kind can kill the fish.. your right.. you need to check for leaching stones, do you have CC or limestone in the tank?

 

[netwireless]

Very little CC, and no limestone.

 

[greenmaji]

I would remove the CC..

 

[netwireless]

Greenmagi, thank you so much for your responses. I'll remove the CC today. I'm going to continue to do partial water changes as well.

 

[greenmaji]

No problem..
If the removal of the CC isnt helping you might want to do a acid test of the gravel and rocks in the aquarium..

 

[netwireless]

Removed all CC, and did another partial water change and so far things look to be more stable and the fish seem to be happy. Thanks for everyone's advices and help.

 

[greenmaji]

no problem