Saltcorner
By Bob Goemans
By Bob Goemans
Hello Bob,
I've read with interest your article about deep sand plenums in a past issue of FAMA. I followed up by reading the article on your website by Roy Meeke 'the Plenum System' and doing more research on the web. I too am of the opinion the marine aquarium should reproduce nature as closely as possible. Back in the early 80's when I started my fish only tank, trickle wet/dry filters were new fan dangle affairs and too expensive for my budget. Bad advice abounded as well and I ended up leaving the hobby (still kept a Koi pond and a freshwater tank).
I've been planning to start a reef tank and I've been reading as much as possible for the past three months and am still three months away from putting water in the tank, as I want to do it right. Based on what I've learned I want to keep the filtration as 'natural' as possible, keep electrical devices out of the water as much as I can and keep gadgetitis under control.
I have a few questions on DSB and I hope you don't mind these newbie questions.
1) Roy Meek suggested a plenum in the sump is not a bad idea for easier maintenance. If I were to follow this, would there be any problem with about 1" of Aragonite in the main tank (for aesthetic purpose)?
2) Could I still keep mangroves in the sump with a DSB?
3) I would like to try placing a flat/flexible waterbed heater under the sump & tank sand bed to avoid electrical devices in the water. Is this a dumb idea and would it affect the bacteria in the DSB?
Thank you in advance for your help.
Regards,
Bert Plourde
Hi Bert,
Thanks for you letter and have heard the same thoughts and questions many times! Your thought as to having an as natural as possible environment goes with my way of thinking. However, when and if complex reef systems are the goal, then some high tech equipment becomes a must if it is to be kept in an outstanding condition.
You may want to read the letter and see the photos of Mike Leppon's low-tech system that is posted in the Photo Gallery page on my website. We actually had over 100 emails between us! Ok, I'm a little crazy, but do like to help people do it right the first time!
As for your comments in question 1, placing the plenum in the sump has not only been my personal preference for many years, but that of most other aquarists. That's because it's the easiest way to maintain it, utilized it efficiently, and prevent that deeper sandbed look in the main show tank, which a lot of aquarists don't like. And a shallow bed in the main tank is exactly what I always recommend in these type situations. And one inch is perfectly acceptable, and should be somewhat course, i.e., 2 to 5 mm grain size so it is not easily moved around by water currents. Its also the right size for better nutrient control as too fine sand leads to more nutrients being produced and stored in the sand instead of efficiently consumed as energy.
As for question 2, whether you go plenum or DSB in the sump, the depth of the substrate has nothing to do with whether or not you can maintain mangroves in that tank. The key factor will be the quantity of light, as mangroves need bright/intense light.
And where question 3 is concerned, two problems arise from heater cables located in the sandbed whether that be a plenum bed or a DSB. The first is that the area nearest to the cable will be the hottest, thereby affecting the well being of any microbes/microbial processes nearby. Also, the quality of the cable itself comes into play, as some are not too well regulated and/or do not dispense heat evenly. However, even more important is the fact that the generated heat rises, and causes rising convection currents that work against the downward flowing diffusion process. It's those downward processes, especially in a plenum bed, that are invaluable when it comes to microbial processes being in a 'balanced' state. Not something I would recommend.
Hope this helps and keep me posted.
Bob
