Cycling question


So I recently got a new AP 24 and started it's cycle with fully cured live rock, live sand and mixed water.
It's been about two weeks and I'm starting to get diatom on the Sand and rock. I tested my water and had some weird results and was told my test kit was wrong. So the question is should my tank be getting diatom before the tanks done cycling, or do you think it's already done?


Active Member
yes it is possible to get a diatom bloom before the end of your "cycle". If you suspect you test kits are bad then take it to a lfs to double check. Why is it a question? If you had truly "cured" live rock you wont see much of a cycle but keep checking and take water to a lfs to be sure they will be happy to check it to sell you something. Just look at the test vials yourself to make sure.


I agree with the poster above.
Get your water double checked, and I actually recommend trying to find a fellow reefer in your area to double check it for you if the LFS is telling you that your test kits are bad.
I've done the "mini cycle" method with fully cured live rock and gotten a diatom bloom without a few days of starting the tank. It's not abnormal. Give it some time. If you have lighting on while you're cycling, cut back on it, this seems to help a little with diatoms. I'm impatient and usually siphon as much out as I can, but they will go away.


Active Member
IMO diatoms should be left alone to run their course, the feed on silicates in the sandbed and rockwork and when the silicates are depleted they will die off.


If you are running your lights it is not required to have them on during the cycle. If you want to have them on just cut it back. It will also help.

florida joe

Well-Known Member
live rock DOES NOT GUARANTEE YOU HAVE nitrification bacteria and or dinitrification bacteria present on or in the rock


Well-Known Member
Just wondering what the "wierd" test results were. If you have no ammonia but an almost immediate jump in nitrates, that is the classic plant life dominated cycle. The plant life (algae, diatoms etc etc) prefer to consume ammonia over nitrate. So as the aerobic bacteria build up the algae is keeping ammonia at bay but consuming nitrates.
Then as the bacteria consume more and more ammonia, the plant life is forced to get its nitrogen from nitrates. So after a few weeks nitrates finally drop down.
my .02