Quick Cycle with lots of mature live rock?


Reefing newb
I am just starting a 75 gallon reef tank. I bought 115+ lb. of live rock that I stored for a couple days in a brute trashcan with saltwater then moved into my new tank which contained fresh saltwater.

Last night, I tested the water for both ammonia and nitrates. Both read 0 ppm. I add 2 nice large raw shrimp and let it sit overnight. This evening, almost 20 hours later I measured both again. I now have 0 ppm ammonia and between 10-20 ppm of nitrate.

So I'm thinking since I have so much live rock that came from a mature tank that the ammonia was pretty much instantly "eaten" by the nitrifying bacteria and then converted into nitrite and nitrate finally. I don't have a nitrite test kit so I can't check for that, but I would guess that if the ammonia was gone so fast so is it.

So is my initial cycle done? I understand that the cycle never stops, but what I mean is that if I let my tank sit for another week do you think it would be safe to add a clean up crew and maybe a clownfish? If so, should I remove the dead shrimp now and do a water change?
I would check for nitrite.
The presence of nitrate is an indication that nitrite is being processed, but is no guarantee that all of them are being processed.
I don't have a test kit for it. I'll just wait a week or two to be safe. I just removed the shrimp. Tested again, nitrates, but still not ammonia.
you need to test for nitrites...get yourself a test kit or take it in, if you are reading 0 on ammonia and nitrite you can do WC's to get those nitrates down
It's alright I've just waited a while to be sure and the nitrates climbed a little bit more but have pretty much settled now. I would test for nitrites but it's not really worth it to pay $25 for a test kit that I'm probably only gonna use now. I've just put sand in so in another week I'm probably going to buy a pair of clowns and a clean up crew.
I just remembered my LFS store does water testing for like 50 cents, whenever I go in to buy something I'll bring a bit of my tank water to have them test.
No need, had my LFS do it, 0 ppm on nitrites, got some fish today, check out my build thread if you're interested.