Top off Water PH

[dwibier]

Hello, I was just wondering if top off water needs to be the same PH as your tanks PH. I have a 35 gal. tank and due to having 2 175 watt metal halides I have to add about a gallon of water a day of top off. I have been having a little bit of a problem with my ph starting in the morning around 7.7-7.8 to 8.1-8.2 at night. I was just wondering if it would be best and if it is the normal routine to make the top off water in normal ranges? My top off water without raising the PH is around 6.2 or maybe a little less.

[romunov]

If you have an automated system, it shoul dose little at a time. pH swings are not a problem, as they occur localy and are "neutralized" fast. If you pour in the entire gallon in the main tank... Hum, dunno, perhaps it could be a problem?
You might also want to see The Reef Chemistry Forum (http://www.reefcentral.com/forums/forumdisplay.php?s=&forumid=112).

[jdieck]

If you are using RO/DI water regardless of the PH it has absolutely no buffering capacity, in other words it will change to the tank's PH in a snap with not effect whatsoever on the tanks PH.
Now if you add two much at once then your issue may be salinity swings rather than PH.

[rshimek]

[moved]

[Randy Holmes-Farley]

This thread duplicates this one:

http://archive.reefcentral.com/forums/showthread.php?s=&threadid=491085

so I'm going to close this thread to keep all of the discussion in one place. :)