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Inert Media VS. PH Dropping Later

Like everyone, I'm having trouble finding media that is inert.

I brought home 2 kinds of river rock and 1 kind of lava rock (red) and was happy when vinegar didn't make it fizz. Then I did what Sylvia recommended...put them in a jar and adjusted the PH down to 6.8-6.9 and checked ph a day later and sure enough the PH had climbed back up to 7.2 in all 3 test jars.

My question is this... Sylvia notes in her book that later on (once cycle and established) there is a likelihood that the PH will drop usually...causing the need to bring PH back up. Why doesn't the tendancy of the rock to "climb" the PH a little in the beginning...get counteracted by the system's tendancy to "Drop" the PH once established.

Maybe it's a rediculous question...but it really has me wondering !

Bradly

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Permalink Reply by Bradly on June 19, 2012 at 11:42pm

I have to hold everything! :-)

I came home tonight and retested the 3 kinds of rock/stone again...and all 3 of them pH is stable.

I'm so relieved....as I now know where to get my media.

Sorry to bother with the above question... now back to the consturction and plumbing work.

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Permalink Reply by Vlad Jovanovic on June 20, 2012 at 1:25am

I dont have Sylvia's book, so maybe it's explained in there...but before you put the media in...you first need to set the water out over night to off gas the CO2. Take a pH reading...then put the rocks in, let them sit out in the water...then take another reading...

Water when you test it straight out of the tap will almost always give you lower pH reading than when you let it sit out for a day/night then test it. Just want you to be sure that it is actually the media that was giving you a rise in pH and not the common phenomenon of CO2 off gassing.

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Permalink Reply by Vlad Jovanovic on June 20, 2012 at 4:42am

Never mind that last comment, I see you adjusted the pH, and probably did it in a way that accounted for pH bounce. Glad you found a suitable media, now get back to work

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Permalink Reply by Bradly on June 20, 2012 at 9:06am

Thanks Vlad...I will benefit from the advice you posted anyway though... your help is much appreciated.

picked up a 30 gal aquarium for starting the babies out in the house about december while it's cold, so it will help me learn about the fish and balancing the water on a small scale etc...

And the aquarium came with 3 butterfly coi, a large goldfish and a plecco...so I'll use these "volunteers" to test the new system in late summer/early fall. I should have it built by then and ready to test on some fall crops for a short trial run.

Vlad Jovanovic said:

Never mind that last comment, I see you adjusted the pH, and probably did it in a way that accounted for pH bounce. Glad you found a suitable media, now get back to work