Quick background... I had a BioCube 29g up and running for 10 days with LR and sand. I switched to a Solana 34g so I took the 29g down, put the rock and sand into a storage container with a couple power heads, heater, and skimmer where it remained for 6 days. When I got the new Solana 34g setup I transferred it over where it's now been for 5 days. I've "feed" the tank 2-3 times over the entire 21 day period a few flakes just to kick start the bio processing.

I purchased the LR locally and it was fully cured. I have never seen my Ammonia, Nitrite, or Nitrate spike or move from levels of 0.

The last time I started a tank (4 years ago) I purchased rock online/had it shipped so there was some die off which caused a normal cycle. I saw my levels all rise then fall off over a 4-5 week period.

I'd like to add a small CUC this weekend before starting to add fish/coral in the next 2 weeks.

Any thoughts on this? Since the rock was cured I have a feeling I won't see the typical spike but I don't want to endanger any inverts. Wait or go for it?

Thanks

I am in the same boat as you on my 180.

I added new sand and covered it with the sand from our 90.

I then added the rock from the 125.

There was an initial spike.

I have tested my parameters and had them tested as back up yesterday and all appears to be normal accept nitrate which was a little high.

My intention this weekend is to do a big water change, put the rock and soft corals from the 90 in the tank this weekend and continue to monitor the water on a daily basis.

Note: I put three damsels in for a period of time before I even thought of putting in cleaners and will probably follow that same script this time.
The first tank I set up used new sand and cured rock and the spike was minimal.

The second tank I used new sand and more cured rock and the spike was zero so I think you are ok but I would keep an eye on it.

If your tank has been up and running for a week now with what should be fully cured rock and sand and all your parameters are showing fine a CUC should be just fine. I just don't like the use of fish to kick start a cycle. If anything, I'll buy uncured live rock and use that to cycle my tank.