Backyard Aquaponics
A place to discuss aquaponics

Hi folks, moved into new home a year ago and finally ready to set up a system. Now that I'm a tiny bit more educated I hope to have better success. Here are my plans. I tried to make a sketch but I didn't have the time to fut around with sketchup.

FT: 300 gallon pond
GB: 1-4'x8'x3.5" DWC culture bed and 1 or 2-4'x4'x10" gravel beds (both lined)

The DWC will be a continuous flow (slow flow). I am planning a simple 2 stage filtration system for the DWC beds. Stage 1 will be a vortex solid separator and stage 2 will be a green scrubby biological filter. So:

FT to filter to DWC bed to FT.

A second pump will flood and drain the gravel GBs. Probably 15 minutes to the hour. So:

FT to gravel GB to FT.
The FT will be lower than the GBs so they can drain straight back to the FT.

I figure that using both types of beds I accomplish 2 things:
1. Increase water volume with DWC bed holding water.
2. Able to utilize both types of beds since they both have pros and cons.
Plus I have always wanted to try the DWC beds.

The FT will be aerated with a 20W pump. I will be stocking tilapia and possibly catfish since I have found a source for it.

I know its hard to give feedback without seeing a sketch, but what do you guys think??????!?!?!

The DWC beds will need to be aerated... especially if you're using "slow flow"...

Shoots, I can't find the resource I read but it said as long as you properly aerate the FT you don't have to aerate the DWC beds if they are relatively small. I'll keep looking for it to reference.

Ok attached is a sketched design. I am not sure if I'm going to use 1 or 2 DWC beds.

Bought the pond. Its this one, pulled the image off the website. Gonna start building things this weekend. I have no idea where to start so I'm just gonna start.

I'm going to try and run the DWC beds without aeration. But I may have to add later. We'll see how things run.

Slowly starting to collect items. Got the pumps, chemicals, ponds, seeds, net pots, rock wool. Going to get the lumber this weekend. I'm in the mood to cut and drill and screw stuff.

It will depend on what you are growing in the DWC as to how much aeration is needed but even plants that are ok with minimal aeration (like lettuce) tend to do better with lots of extra aeration.

The aeration in the fish tank will likely have minimal impact on your DWC since the water will be going through filtration first and the bacteria in the filters will use up lots of dissolved oxygen before the water gets to the DWC.

Luckily it's pretty easy to add aeration to the DWC later.

I'm going to venture to say that you might want to invest in a good big air pump that can deliver between 1 and 2 CFM of air to give you plenty for the fish tank as well as for the DWC and perhaps the filter as well.

+1

Hmm Ok. I purchased an Alita air pump that is rated at about 1 CFM. I'll probably have to get another one. I found 2 articles. One was a hydroponics study proving aeration had no effect on growth of lettuce. I can't find it but here's another article opposing it saying aeration is important. Good read, I recommend it.

http://www.uky.edu/Ag/NewCrops/brassicamq_tw.htm

Ok I have a question. I have 2 options right now in regards to aeration.

1. 20 watt air pump with diffusors
2. 10 watt water pump with fountain attachment (or make one diffusing the water as much as possible)

Would one significantly aerate the water more than the other or is this a stupid question? If possible I'd rather run the water pump since its cheaper and cheaper to run. what do you guys think?

HN

An air pump that can do 1 CFM will take care of your fish tank aeration needs plus a little extra left over that could perhaps be enough for the DWC beds maybe. Trick is balancing the air flow so you still get enough air in the deeper fish tank when you add stones to the DWC.

While I understand the desire to use a water pump to provide the aeration, I've found that the very small water pump will get gunked up so quickly that it really isn't effective. That is my experience. The air pumps don't clog daily and if you get high quality air stones, you will be able to rejuvinate them when needed (I have not needed to do anything to my air stones so far-had them about a year, I got really big ones too.)

I've also found that the extra water movement and circulation you get from having air running in a tank greatly improves the cleaning of the tank allowing the solids to move out of the tank and into the filters.

Thanks TCL, will do. I'll try and make do with the pump that I already purchased. I got good stones, washable 10 inch alita stones. I have the air manifold so I can adjust air flow. I'll see if it can push enough air. If not I'll have to invest in another. Gah!

So far the cost of this build has hit $645 bucks and I still haven't bought all the lumber and liners yet. Yikes!

Yep stick with the air pump you already have and that will at least get you started. it will be some timer before you would need additional air anyway, it will take some time for the grow bed to get cycled up anyway as well as the filters for the DWC.

I have a question for you. Why are you not connecting the DWC to the gravel bed, making the DWC your sump and pumping back to the fish tank from there? There are many advantages for doing so- 1) you only need one pump to operate the entire system and you can use your second pump, if you have purchased it already, for redundency; 2) the water going through a flood and drain gravel bed will re-aerate with about 25% free oxygen and will reduce or possibly eliminate your need for additional aeration in the DWC; 3) you will have less plumping expense with one loop, instead of two loops; 4) the gravel bed will become your bio-filter, eliminating the addtional costs of the swirl filter and the added scrubby filter- add them later, only if you need additional filtration; and 5) you get the biggest bang for your buck retaining and utilizing all the nutrients, including those that will be created through mineralization.
You can set the system up so that the only place the water flucuates is in the DWC area, the fish tank will remain at a constant height, whether one, two or no pumps are operating.

Angie let me make sure I understand. You're saying I go from FT to gravel GB then to DWC back to FT? This means that FT is the highest, gravel GB is the second highest and then DWC is the lowest? If this is the case it's not going to work because the FT has to be the lowest.

One option I will consider because of your post is FT pumps to gravel Gb then drains to DWC then back to FT.

Hmmmmmm

What Angie is actually suggesting is a bit of a system re-design from what you were proposing.
Basically make the DWC tank bigger so it can also be your "sump" tank so yes it would be the lowest. Think CHIFT PIST. Have the Fish tank water level be the highest (the water level needs to be highest, the bottom of the fish tank can still be below the top of the gravel) and it overflows into the gravel bed which can then drain into the DWC sump. This means that the DWC sump needs to be big enough to flood the gravel grow beds with enough excess to still allow the plants in the DWC to not "ground out". It is really just a different way to lay things out. You get the benefit of CHIFT PIST for the fish tank and the gravel acts as the filtration for the DWC.