View Full Version : Plenum find

05/20/2007, 07:21 AM
I run a plenum with about 5 inches of substrate. The plenum is about a little over an inch high. Its high enough so i could view under the substrate and into the plenum. There i see feather dusters growing, hanging upside down from the substrate.
This is my third plenum setup and i never saw anything growing under there before.

Matt Mitchell
05/20/2007, 08:59 AM
I’m under the impression a tank shouldn’t have any light to enter the plenum area. Have you noticed any spikes or hair growing? I’m currently on my second plenum tank and I spent some time to make sure to close off the plenum from light and now I’m wondering if it’s not necessary.

05/20/2007, 01:11 PM
I have never tried to close off light from that area. I did not know it was suppose to be totally dark. I never had any problem because of the ambient light. My first plenum lasted 7 years before it was taken down

05/20/2007, 01:25 PM

do you have a photo of the plenum system?

05/20/2007, 01:53 PM
That is pretty cool and I would not have expected fanworms to get enough food in the fairly static water flow conditions under the plenum. It also indicate that the plenum O2 level is not so low as I would have expected. A picture would be great. How long this plenum been set up? You using crushed coral or something different?

05/20/2007, 03:07 PM
Its a new setup about 4 months old. Crush coral and aragonite sand combination.
I don't know if the feather duster can survive over time, I will keep watching to see.
Had algae bloom at start up and its now receding fairly quickly. I do have a a lawnmower blenny that eat the algae

Steve 926
05/20/2007, 04:40 PM
Hello To All :)

Glad to see a thread on Plenum's !!!

I am currently in the process of setting up a 50 gal. with a CPW plenum.

A very interesting read even though it's a long one !
it was resurrected by a member, using one for several years now.

I have made one slightly different, just my $.02 worth, and I was looking for some opinions on the substrate layer choice

I plan to use a 2 ~ 4+ mm. aragonite sand / gravel as the first layer. I was considering a fine aragonite sand, .5 ~ 1.0+ mm as the top layer, separated by a landscape cloth to prevent the finer sand from mixing through. eventually I would like to add about 10 lbs of a reef substrate, (small mm. version of a c/c) to the top layer also just for diversity.

What's your opinion :rolleyes:

All comments are welcomed :D

All flamers must get in line :p

Steve (@^ 926


04/26/2008, 09:41 AM
got around to that picture feather dusters under the plenum. The substrate is about 5 inches deep.

04/27/2008, 12:32 AM
Sounds like you have had plenty of experience with plenums, but is not the idea that you want to create an anoxic area for anaerobic denitrifying bacteria? If the worms are down there I suspect it is not anoxic.

04/27/2008, 06:47 AM
Its must not be but i thought that it was to low oxygeniated area not no oxygen area. Whatever its suppose to be it works for me.This one is setup two years now. On the old system i had I never saw anything living in that area.