High ph

[ryeguy]

Hi there, I'm looking to get some locally bred discus here in Canada...The ph out of the tap is 7.4 and fairly clean (we drink it without any issues)...After the water sits in the holding tank for a day with aeration, the ph rises to about 7.8-9....Will this be an issue? and why does the ph rise?

[FishLover]

First of all, the fact you can drink your tap water without any problem does not mean it is safe for fish. Most of us can drink our tap water without any problem but the same water will kill any fish within few hours without de-chrol it first.

The pH rises after the Co2 is aired out. Mine does the same, about .6 to .8 pH jump. It is not good for discus without aging water in this case because every water change, you will see more than .3 pH swing within 24 hours, which is bad for any fish, especially for discus.

You have few options:
1. Age your water. Some people are able to keep discus in high pH water, as long as it is stable. Some people don't like it because this could stress the discus in the long run. Not sure who is right and who is wrong. IMHO, my discus show off better colors with pH less than 6.5
2. Use something that will bring down the pH and helps it to stay down. I use Discus buffer to keep my water at 6.3. Some people don't like to use it, especially for people trying to breed discus. So far I have no problem with it and I don't breed them. If you decided to go this way, make sure you treat your water before put it in the tank.