Why do I need a plenum before adding LR to a new tank?

[Mrsfuller2572]

I was advised to set up a plenum before adding LR. Can anyone PLEASE tell what this is and why I need it?
I have a 55g. that is not yet set-up. I have the powerheads, and ordered the skimmer. As soon as they're both set up and ready, I will begin cycling the tank with substrate only.
Thanks.
It's all greek to me...and a bit overwhelming, I might add!

 

[ryguy]

Hey,

Allow me to clarify and confuse the matter even more. Just to give you a heads up...You WILL go through periods of confusion with this hobby, they come in waves and the frequency of these waves is directly related to the amount of reading/research you do. Research is GREAT, but it opens up many more doors to things you didn't anticipate, and will seem to complicate everything just a wee bit more.

You don't need a plenum before adding LR, because, quite frankly, they aren't usually even recommended or used that much anymore. A DSB, (deep sand bed), is generally regarded as the most successful option for your denitrifying substrate method. I won't bother going into too much depth, but the DSB, used WITH your LR for biological filtration by providing surface area for beneficial bacteria to grow. A plenum is a layered substrate bed elevated with a platform that allows a space underneath as a dead water zone, which is believed to stop the accumulation of nitrates.

There are a couple of different points of view regarding having a sand substrate present during LR curing and cycling in the setup of a new tank. If the LR has lots of die-off, some believe that it will accumulate on the sand, get mixed in and rot without getting a chance to be purged from the system. Others believe that after time, you'll be good to go and that its not a big deal.

If you have a good skimmer and LOTS of circulation from powerheads, then you'll be fine with putting the sand in then the LR, and starting your cycle. If not, you can just put the LR in cycle the tank while curing your rock and use a pvc pipe/funnel to pour your sand through (to avoid a sandstorm) after the cycle.

Another option is to cure your LR seperately, but if you can live with the smell in the house, and it probably will smell pretty foul, its most beneficial to cure it in your main tank, plus its cheaper.

 

[demodiki]

Good post. No need for a plenum...not even adviseable really, for someone new IMO.

 

[Guest]

its also ok to cycle your tank with uncured liverock too right?

 

[BillyZ]

its also ok to cycle your tank with uncured liverock too right?

Yep