Plenum

Let's talk about Plenums.
I'm thinking about adding a plenum to my soon to be sump. I've been reading around and have found that a plenum is very benneficial to the denitrification process. And, that it has a lot of similar benefits as a DSB. For more details go here:
http://www.thereefweb.com/starting_a_foolproof_marine_tank.htm#4. Substrate.

So I'm wondering how deep to make my sandbed in the plenum and also in the display tank. Right now I am thinking that I would have 5" in the plenum and 4" in the display tank.

Let me know what you think! :thumbsup:
Thanks,

 

Heh. The big 'P' word eh?
Well this is certainly a way to get some fish heads hot under the collar...

A little history. When I started my reef tank in the early '90s the plenum/dsb debates didn't exist. People were trying 'berlin' methods without substrate, others were using crushed coral and some, including myself were trying sand.

Then word crept out about tanks in Monacco that Dr. Jaubert had going using a pvc foundation under the sand. I believe around the same time, I may be wrong, that there were people here in the states like Sam Gamble that were studying why tanks with undergravel filters in them did better when the power was off!

From there the plenum started to become widely adapted.
However, as sand became more and more popular, many people began foregoing the plenum and just putting sand in the tank.

I would speculate that this had a lot to do with people being intimidated by making a plenum and being encouraged by some success stories of tanks without a plenum. Also they may have heard stories of tanks having problems with plenums. You still hear these today, but I have yet to hear one from a direct source. It is like an Internet tumbleweed based on hearsay. I believe some may be true, but I would be willing to bet that they didn't construct the plenum very well.

It may be too early to tell, but I think I am seeing things go full circle as some that are not completely happy with DSBs asthetically or functionally are looking for alternatives. This has also been fueled by the DSB man - Dr. Ron Shimek's recent tank crash and his speculations about 'old tank syndrome' which turned some people off.

My take - both can work well at what they are supposed to do - lower nitrates. BUT they are not the end all be all and will not make or break a tank. What I mean is that they are one piece of the puzzle and other things: water quality, lighting, filtration, tank husbandry, etc.. are equally if not more important.

I tried to put everything I know in the sand section about setup. Check it out:

http://www.3reef.com/sand.htm

Basically, build your plenum with pvc/eggcrate/plastic window screening and put 4 inches of sand on it.





matt

 

Well Put!
Thanks! So as far as a dsb also, I'm thinking only 4". Nothing too drastic

Thanks,

 

Thanks!
I think 4" would be fine, I had around that maybe a little less.

I read a lengthy discussion (6 page) last night about alternatives to DSB. Some are going with bare-bottoms (*Berlin method) as a kind of a knee-jerk reaction to the metals and 'old tank syndrome' scare. Some are just going with a couple inches of sand. Some piped up and said they have tried them all with success, others mentioned problems.

This all leads me to believe that there are many viable ways that can work. The key is to find the one that works for you.

*If you are curious about Berlin tanks, my take is that they work, but require more water changes to prevent algae blooms. If you get the husbandry down, they can last. Of course proper husbandry is fundamental for any setup.