New to aquaponics

[Dan Keith]

I started to raise talapia in the early 70's and never really got much done. Now I am back to it, late bloomer I guess:>) I built a solar green house a year ago and decided to go the aquaponics route. I have built a grow bed from reinforced concrete and need to figure how big of a sump I need. I bed is 24' x3'x12"deep and should hold about 540 gals. My question is, with the grow medium in the bed what is the approximate gallons required to flood the bed? that number would be the capacity of the sump. Also I will need to seal the concrete to water proof it,does anybody have suggestions or experience with acrylic type roof coatings? Thanks, Dan in the bad lands of New Mexico :D

[Jon Parr]

Media takes up about 2/3 of the volume, water 1/3. I recommend the top 2" stay dry to deter fungus gnats, which reduces a little more volume. So, 200 gallons ought to do, but a little extra is always nice to hold enough for a couple weeks worth of transpiration and evaporation.

Some have sealed with epoxy, bitumen, or even melted wax. No experience there, sorry.

[Dan Keith]

Thanks Jon that is the info I needed. I will post the ongoing project and results. Dan

[Jon Parr]

Check this thread, might yield some goodies.

http://community.theaquaponicsource.com/forum/topics/seal-concrete-...

[Dan Keith]

Thanks again Jon, There seems to be many ways to skin a cat..huh ...fish. I will be sure to post results. Dan

[Larry D. Hays]

Hi Keith, I have a 30 X 40' Rainbow Trout Hatchery Building that I want to convert to raise Tilapia. I will pipe it to a 96' X 30' greenhouse where I want to build 4' W X 16'L X 14" tall concrete Growbeds. I would like to build a two part mold to shape the insides. I know it is very important to seal the interior. I read your interest in Concrete Growbeds and wondered if you have pictures? Also any tips you might have in building them or using them. Larry at
www.redhillslake.com
[e-mail]

[Larry D. Hays]

Sorry I got your name wrong Dan. I'll get it right from now on. Larry

[Dan Keith]

I am heading out the door but will get with you this evening Dan

[Alex Veidel]

I don't know what media you're planning on using, but i found that hydroton displaces about half your water volume. Oh, and a word from experience, after filling your sump tank, make sure you leave enough water in your sump to completely cover your pump so it doesn't run dry :) This looks like a really cool setup; I like your green house.

[Larry D. Hays]

Very good Dan, I will watch for your answer. Larry

[Dan Keith]

Hi Larry, My approach is pretty much what you see in the photos in my original post. I used plywood for forms pretty strait forward method. Obviously you need a strong base or just cast them on the ground. A slip form would do the trick and make in sections. I used rebar to reinforce and with that you could go pretty thin. Mine are 4 inches thick mainly for the thermal mass. For the base I have adobes filled with dirt. Down the middle of the dirt I have a 12 inch steel pipe which is the exhaust of the rocket stove mass heater ( http://www.richsoil.com/rocket-stove-mass-heater.jsp ) I have in the green house . I run a small fire during the day to warm the mass and it carries warmth thru the night. I have yet to finish the tank but will do that soon. As to sealing I have had good luck using a product named snow roof. It is a elastomer acrylic material sold under many brands. Just paint it on water based tuff. Dan

Alex thanks for the comments, everything I do is scrounged material and dictated by a lack of funds, at leased when it is done it is paid for :>)