Backyard Aquaponics
A place to discuss aquaponics

First off, thanks to everyone for contributing to BYA. My father and I have enjoyed scanning this site for inspiration and guidance on designing our first aquaponics system. We were starting off slow, but yesterday we found out that the area supplier of catfish fingerlings won't be making any more rounds to sell this year EXCEPT tomorrow..and for only US$.55 each!! So, we spent most of last night rigging up our current supplies and letting the water begin to dechlorinate.

We are starting with 2 x 100 gallon rubbermaid tubs (catfish tank drains into the sump), a few large trays and lengths of 4" PVC for growbeds, and a 40 gallon tub at the bottom for clean water retention to be pumped back up top.
But, I have a few questions:

1)Are lava rocks the best media for the sump?? We have the 100 gallon rubbermaid filled 2/3 of the way up with washed lava rock...is 300+ cm the appropriate level?
2)I have heard that people use Molasses to activate the microbes in the sump, can someone please explain or link a good article..I haven't been able to find an article specifc to aquaponics, just for vermicompost teas.
3)For best filtration, where should the inlet and outlets be for the sump?? Should the water cascade in from the top and be taken off the bottom ---- this is my main hold up right now
4)Can I effectively grow duckweed over the sump? Or, does the sump benefit from oxygenation from the disturbance of the water surface(therefore impeding the growth of duckweed)?
5)Are hydroton grorox HAND-DOWN the BEST for growbeds?

1 - There usually are not any rocks in the sump?? But there is no reason why not except for lower water volume...

2 - Heard of it, dont know any specifics, not required if your getting fish anyway, all the bacteria will be with them, and in the atmosphere.

3 - Water splashing into the top of the sump for air, pumped back up from the bottom.

4 - Duckweed wont grow in a sump, unless you have it in a sperate floating container, tethered to the opposits side of the sump from the water inlet.

5 - Yes. Comes at a cost though.

I must be using the wrong terminology. By "sump", i was talking about the place that the fish water goes to to help process the ammonias into nitrates before going to the plants.

Maybe post a pic of your planned layout, so we can see what you mean...

I'll try to post a few pics later today. But, basically the plan is:


Catfish Tank (100 gallon) --> "Decomposition" Tank (100 gallon) --> Grow Bed trays --> Clean Water Reservoir (for pump to fish)

At this point, I don't know exactly where I got it in my head to put a "decomposition" tank in, maybe it was before I started to understand that the bacteria cultures live in the grow beds under the plants...

Youve got it arse about - Catfish tank - Grow beds - Sump - catfish tank.

The sump is the clean water reservoir.

If the grow beds are filled with gravel (or whatever media like lava rock, river rock, hydroton, growrocks etc. just avoid limestone or marble for pH reasons) and flood and drain, then the growbeds function as both the plant growing space as well as the bio filter and solids filter. If the grow beds are like Deep water culture or NFT then you will need some sort of solids filter and bio-filter before the plant sections.

You could have the fish tanks overflow into media filled grow beds and they could drain into a sump tank where the pump could lift the nice clean water back up to the fish tank or NFT pipes could get the clean water and they could drain into the fish tank.

Catfish do like quite a bit of aeration and well filtered water or they can get stress related illnesses. Since you are getting fish before you are really prepared, start airing as much extra water as you can to be ready for water changes and be sure not to feed them the first day and be very stingy with the feed, if they don't eat it all quickly, scoop out the excess since overfeeding can really mess up the water quality quick. I'm just recovering from an overstocking/underfiltering situation where many of my catfish were not doing very well. We were really worried that we were gonna loose the whole batch of catfish we had. If you can get quite a lot of extra aeration, it might help your cycling go a bit faster and help your catfish survive the process. Catfish don't like too much salt but between 1-3 ppt might be good to have in the system to help with the transition and help protect against the nitrite spike that will happen during cycling.

Good luck, adding fish to a system in a rush is always a bit more stressful than getting the system all set and fishlessly cycled before getting your fish stock. Try to restrain yourself on numbers, too many fish for your system might leave you with no survivers. For a brand new system try to go with only 3 (or less) fish per each 25 gallons of gravel or media.

I think OBO and TCLynx have covered it, but this link may also help with some ideas :

http://www.backyardaquaponics.com/designs.htm

As OBO outlined, the standard layout (water flow) is usually:
Fish Tank => Grow Beds => Clean Water Sump => Fish Tank

Most of the tweaking comes with how the water gets into the beds (pump, gravity, etc) and drains out of the beds (standpipe, siphon, etc), and how it returns to the fish tank (pump, gravity flow, etc).

When setting up the system, think about what will happen when there is a power cut, pump failure, etc. Where will the water flow to, and how will the fish (and to a lesser effect the plants) be affected. Will the fish be ok if you're not there?

If possible, it's good to have some sort of redundancy in the system (backup battery, larger than required sump, additional FT air supply, etc).

Thanks again. All 27 catfish are doing great split into the 2 100g tanks. I'm using standard aquarium pumps (protein skimmers, hanging filters, and tons of airpumps) until the hydroponics part of the system is complete. Thanks for all the advice to acclimating the system first.

The system design is finished, I should have it done tomorrow. I'll post pix when I get an opportunity to use my bro's camera.

Too many projects going at once...one of my little chickens is hatching out her eggs today
I've hatched with incubators, bought from the store, ordered online..but this will be my first time experiencing the wonder of our favorite hen showing me the right way to do it

Plus, we got one of the WORST hail storms on record last night...I was surprised to see it on yahoo's main news page.

isn't life on the farm grand!!!! Even when you don't really have a farm. I got home from work today to discover that two of my hens had free ranged themselves out of the extended run area...... I'm too busy this week to be worrying about the chickens running loose in the neighborhood.

Anyway, keep the feed way low and I hope you picked up the aquarium test kits for checking ammonia, nitrite, nitrate and pH. Keep an eye on your ammonia levels in the fish tanks. keep the fish very hungry until you have more filtration online and then only slowly increase the amount of feed while keeping an eye on your ammonia and nitrite levels.

good luck with the chick!