New Tank Cycle

Dave Bees

Reefing newb
Hi everyone I'm very new to saltwater fish keeping.

I have recently purchased a 25 gallon Fluval M90 Aquarium ,well 26 days ago to be precise.
The problem I have is I don't know if it's cycling as the test results seem to go up and down
I have approx 18 kg of cured live rock 10 kg of Carib live sand and nothing else in the tank apart from a lot of brown nasty stuff on the rocks and sand.

The Rock has been in the tank 21 days now and I haven't seen any living thing at all. I have included a few pics and my test results and was wondering if anyone out there could give me some idea of what's happening,many thanks in advance...
Hi Dave and welcome to Living Reefs!!

What kind of test kit are you using. Sometimes API will give you false positive readings. It is a little more difficult to notice a substantial cycle when you use cured live rock. Looking at your numbers it appears you had a cycle. Now I believe you are getting some bogus numbers on your ammonia and nitrites. You have diatoms which comes with a new setup. I would do a 10-20% water change and see where your numbers go. I would also mix your water change with your SG around 1.027 and try to bring up your total SG to the 1.025 number. Let us know what happens. Good luck!