New Tank Nitrogen Cycle

[Bat_2k3]

I have a 40 gallon breeder that has been running for about 2 months now. The tank was setup with Carib Sea Live Sand and 60 lbs of Marco rock. I initially used dechlorinated tap water to fill the tank but now only top off with distilled water. Unfortunately RO/DI is not an option for me because the closest LFS other than Petco or Petsmart is 2 hours away. I have a pretty good understanding of the nitrogen cycle already from the three large freshwater tanks I still have. I was not able to find a saltwater test kit at any local stores here until recently so I was never able to check initial water parameters. I have been testing daily now for six days and my current levels are:

PH - 8.1
Ammonia, Nitrites, Nitrates - 0
Calcium - 460 (had some issues initially trying to raise levels from 220)
Carbonate Hardness - 9
Phosphate - 0
Salinity - 1.022 (was 1.024 yesterday but spent the last few hours acclimating clean up crew)
Temp - 78.4 (max throughout the day is 79.3)

Over the past week I started having a diatom bloom which my snails and crabs are currently devouring like crazy.

My question is since I never was able to see if there was an ammonia spike and then a nitrite spike, is it possible that the cycle never started or does the presence of diatoms mean that it definitely has.

I'm planning on adding 2 clown fish but I want to make sure the tank is ready for them. This tank is in my 4 year old daughters room and don't want to take a chance on killing Nemo in front of her.

 

[reeftivo]

perams appear fine but bump up the specific gravity to at least 1.025 (1.026/35ppt ideal). Some nitrate isn't bad during cycling, but I didn't see that on your list of tests.
You should also keep an eye on that as the tank matures.

Fish can tolerate lower specific gravity much better than inverts, but most LFS have their systems at or around 1.025/.026 so fish may get a little stressed.

Marco rock can take a while to fully populate with bacteria and live sand (IMO) is not much more beneficial than dry sand. Just give it time.

 

[bertoni]

I suspect that the tank is fine. You could add a tiny amount of fish food to see whether that is turned into measurable ammonia. Maybe 1/4 of what you'd add to feed the fish should be fine.