View Full Version : Cycle Question

09/29/2017, 11:30 AM
I am about 4 weeks into a new tank cycle, I just had a brown algae (diatom) outbreak. I understand why this happened and know that it is somewhat normal. My question is there is no CUC in the tank now, is it a good idea to add some now, or wait until the bloom dies back down a bit. Thanks!

09/29/2017, 12:05 PM
If your Ammonia and Nitrites are at 0 then you should be good to go with a CUC.

09/29/2017, 12:15 PM
yep.. assuming you started with dry rock and or shipped live rock..and not locally sourced live rock that is already cycled then once ammonia and nitrites have risen and come back down to zero the "toxic" portion of cycling is over and you should at that point start adding your CUC to do what they do..

If there is any sign of ammonia or nitrite then you are still cycling and need to wait as those are toxic to some level..

09/29/2017, 05:37 PM
I might wait for a week of zero ammonia before adding anything, since tanks with live rock (as opposed to dry rock) sometimes have secondary ammonia spikes. A bit of nitrite is fine, but waiting for it to hit zero is okay, too. An herbivorous snail or two per 30 g of tank capacity probably is fine once the ammonia is under control.

09/29/2017, 06:05 PM
Thanks for all the reply's. Yes I started with "dry" rock and live sand. I will add some snails this weekend and see how it goes.

09/29/2017, 06:37 PM
You're welcome. That sounds like a good plan to me.

09/29/2017, 07:34 PM
Bulldog - Yes, as other members noted you should be fine with adding snails or hermits (or both) from the water's potential toxicity aspect (i.e., your ammonia and/or nitrite levels have fallen back to zero).

However, one thing to consider with respect to whether you add snails/hermits and how many is that your tank at present may have very little food for them to eat. Neither type of critter is known to eat diatoms, so until your tank grows some red/green algae or you add fish that you're feeding, you may want to consider actually feeding the CUC. For the snails, dried seaweed (nori) from the supermarket would be suitable, and for hermits, a little bit of flake (or preferable) pelleted fish food would work.

09/29/2017, 07:49 PM
Most of the Trochoidean snails eat diatoms. A few abalone and limpets will, as well.


10/01/2017, 08:39 AM
Whoops! You're quite right, Jonathon. That's a case of "engage typing fingers before engaging brain". I was thinking of dinos, not diatoms.


10/01/2017, 03:50 PM
Ah, that makes sense. Dinoflagellates are far more problematic. I dosed my tank with silicate for a while to encourage diatom and sponge growth. The diatoms might not have increased in numbers, but they certainly didn't build up, given the Trochus I had in the tank.