When is it 'safe' to put homemade rockwork in?

[shollis2814]

OK, so I am 'kuring' some liverock put together with hydraulic cement. I have it in a 5 gallon bucket and I am filling the bucket and testing the water each day, then dumping it and refilling.

In the beginning, the ph was maxing out and the alkalinity was dropping down really low.

Today, the ph rose slightly, and alkalinity seems to have actually gone up from the water out of the tap (out of the tap at 3, went to 5 overnight).

The next step is to put some RODI saltwater in and see how that gets effected overnight in regards to pH and dKh. My question is, could some of the old live rock also be having an effect on my hard/slightly basic Nashville tap water?

Should there be *zero* change to the RODI salt, or is a point of alkalinity swing acceptable?

 

[Randy Holmes-Farley]

Cement would often raise pH and alk. I'm not sure why you saw alk declining. Maybe something in your cement.

The idea is to not have pH and alk rise above acceptable limits. How much that is will depend on what else is in the tank reducing pH and alkalinity.

If you think it may be done, I'd put it in salt water and see how high the pH and alk get.

Calcium carbonate rocks will raise the alk and pH of Ro/DI, but not salt water at normal ocean parameters.

 

[shollis2814]

Thanks. Would stability for 24 hours be enough to declare it OK, or should I leave it 2-3 days.

 

[Randy Holmes-Farley]

I'd watch a few days with stirring. :)

 

[shollis2814]

Good call! Alkalinity seems to have stabilized. pH is getting there. It creeped up .6. So, I dumped that water and trying again.
*whispers* Nothing good happens quickly in a reef tank....nothing good happens quickly in a reef tank.... :D