pH issues...

[kzimmerman]

what is the biolad of each tank? Feeding regimen? water changes? The biolad of the tank can decrease the pH of a tank, by eating up the carbonate hardness with the acids produced by biological processes. It also could be something that is in the rocks, or substrate, other than carbonate hardness, that can function like carbonate hardness. I don't have any idea of what that could be, I don't pretend to know everything about water. My brother in law, however, is a wastewater systems engineer, and is actually quite well versed in chemical processes in aquariums. I'm gonna see him this weekend, I'll ask what he thinks if I get a chance (theres gonna be 5 grandchildren running around, all under the age of 5.)

 

[Knowdafish]

"(theres gonna be 5 grandchildren running around, all under the age of 5.)"

 

[kzimmerman]

Yeah, tell me about it. My sons the youngest, he's 4. The others are all girls. Poor little fella.

 

[brianp]

Something is probably raising your carbonate hardness. Do you have any coral, coral rock, limerock, seashells, or anything similar in it? Any rock with any degree of white in it should be checked. A quick check is the acid test. Take the rock and drip a few drops of pH down on it, or vinegar. If it bubbles, it will raise the carbonate hardness of your tank, thereby rasing the pH. What are you keeping in it? Any particular reason your worried about the pH?

Closed biological systems will always acidify over time. The most likely explanation for the phenomenon that you report is the substrate raising the KH. This may not be a bad thing in the sense that whatever process is occurring is apparently counteracting the natural acidification. As long as the pH doesn't exceed what you view as acceptable for your particular fish, maybe you should embrace it. What is the pH in the 300 immediately following a wc? What is the pH 5 days after a wc?

 

[Aquafreak]

what is the biolad of each tank? Feeding regimen? water changes? The biolad of the tank can decrease the pH of a tank, by eating up the carbonate hardness with the acids produced by biological processes. It also could be something that is in the rocks, or substrate, other than carbonate hardness, that can function like carbonate hardness. I don't have any idea of what that could be, I don't pretend to know everything about water. My brother in law, however, is a wastewater systems engineer, and is actually quite well versed in chemical processes in aquariums. I'm gonna see him this weekend, I'll ask what he thinks if I get a chance (theres gonna be 5 grandchildren running around, all under the age of 5.)

Thanks a bunch!

Closed biological systems will always acidify over time. The most likely explanation for the phenomenon that you report is the substrate raising the KH. This may not be a bad thing in the sense that whatever process is occurring is apparently counteracting the natural acidification. As long as the pH doesn't exceed what you view as acceptable for your particular fish, maybe you should embrace it. What is the pH in the 300 immediately following a wc? What is the pH 5 days after a wc?

Some keep their cichla in water that's 8.0, and I guess it's acceptable, but I'm not willing to stop finding a solution until I find there is no solution! My tap water tests a consistent 7.0. Water in the tank after a 50% water change is 7.5. 5 days after a water change, the pH is 8.0.