How long does it take for a new (dead and clean) LR to fill with bacteria?

[Paradiddle7]

I took half the LR out of my tank, acid cleaned them, rinsed them, dried and then put them back in my tank. How long will it take for those cleaned LR to repopulate with bacteria, so that I can do the other half? I had major phosphate build up and I need to rejuvenate the rock.

 

[ridetheducati]

Bacteria will populate the rock as the nitrogen demand increases. The system will most likely go through a nitrogen cycle.

If it was me, I would have cooked 100% of the rock and implement a mechanism to combat leaching PO4.

 

[Paradiddle7]

What do you mean? Are you saying that my cooked rock will now be leaching all the PO4 from the uncooked rock?

 

[Dmorty217]

30 days or so

 

[ridetheducati]

What do you mean? Are you saying that my cooked rock will now be leaching all the PO4 from the uncooked rock?

It depends on how much life the rock had before you cooked it. Bacteria, flora, and fauna on and deep inside the rock will decompose and phosphates will develop and be transferred into the water column. During the cooking process, some hobbyist run Lanthanum Chloride to combat PO4 that may begin leaching.

The cooked rock may leach PO4 until the sink is empty. I understand that your existing cured rock is already leaching PO4, which is why you are going through the cooking process. As I mentioned above, best practice is to cook ALL the rock at one time. Splitting the process into two sessions means that the system may be go through a perpetual nitrogen cycle lasting at least a couple months.

 

[ridetheducati]

One other thought, are you using a sand bed? If so, removing 50% of your rock may not be as bad because the sand bed is carry a lot of bio.