Originally Posted by beckyforvols
... I checked the nitrites in the 10 gallon before transfer and they were negative. Of course we could have stirred up something when moving the sand. ...
Oh... you moved the sand over too! I think we were missing that piece of information. Normally, folks won't reuse sand when switching tanks because of all the nasties that are deep inside it. Those nasties are find as long as they stay in the sand, but once disturbed... from either a real deep vacuuming/cleaning, or from a transfer... they can really muck up your water parameters.
Most likely, you stirred up a fair amount of stuff that your existing biological filter couldn't handle, so you ended up with another cycle. Not sure how long it will take for your bacterial to catch up, but I'd keep an eye on those water parameters and have plenty of premade saltwater ready for water changes just in case.
Just FYI... the bubble disk isn't really doing anything for aeration of your tank. That's more a freshwater thing. But if you like the looks of it, that's another thing!