Backyard Aquaponics
A place to discuss aquaponics

tomm77, the title probably turns people off but that's okay. I post just the basic questions here but most of my build details are on my website or blog. I don't get much response from my blog readers but I get a lot of readers on the blog. it's strange. This build has been long with little progress for weeks at a time due to weather or other commitments. I'm finally getting back to it now that the greenhouse and storage buildings are finished. Plus, I've decided to go much smaller on the initial AP build to get some experience. I'm not planning on this being used from a commercial basis like Ryan's business. I do sell some of my excess vegetables from the dirt garden at a farmer's market but the AP won't be a commercial thing.

I'm planning a hybrid type system where I'll have some growbeds AND some DWC but the DWC will be a little bit down the road. I'm still new to some of this AP stuff but have plenty of gardening and aquarium fishy experience.

HairyCamel, that's a good idea about the overflow back to the sump but since I'm already going to be overflowing into the growbeds from the FT, not much point in my mind in another overflow. I will be diverting some of the water back to the sump for aeration. I'm sure I'll have to play around with the flow rates.

The Aquaponics system has made some major progress since I last wrote about it. The growbeds have been positioned, the bell siphons build & installed, and the gravel washed. We found that the Quikrete All Purpose Gravel (50lb bags) that can be purchased at the Big Orange (you know the one) big box store doesn’t react to the vinegar test so hopefully no issues with PH buffering. We tested the gravel by pouring some vinegar on the gravel and had zero bubbles. That is a good sign so hopefully we will be PH neutral.



Both growbeds have been filled with washed gravel (the picture above was taken prior to the 2nd bed being filled with gravel btw). Of course, there is absolutely no way to wash the gravel to remove ALL of the dirt so we did experience some fine dirt covering the fish tank and sump tank. Once the water has cycled through the gravel for a few days and the suspended particles have dropped to the bottom of the tanks, we will vacuum it up.

I added some Maxicrop liquid seaweed fertilizer to the water to help the plants get started while the tank is cycling. I threw in some leftover seeds from the herb garden as well as some lettuce just to see if they would grow. After just 2 days, the lettuce has already sprouted and is growing. Pictures to come. We also have some thyme sprouts coming up after just 3 days. I also had 6 tiny basil seedlings that were put into one of the growbeds and they appear to be getting established also!



The next step is to order another fish tank as well as more growbeds in the coming months. I don’t think we will have enough growbed filtration for the tank size so two more growbeds will be added before the 2nd fish tank is setup.



I just want to say that I am pleasantly surprised that the bell siphons were very easy to build and they worked the first time I filled the gravel free growbeds! They both kick in within 10 seconds and burp once or twice once the bed has drained. I’m getting about 6 fill/drain cycles per hour which I calculate as around 250 gallons per hour. I think this is a little bit low since the pump has a head of about 380 gallons/hour. I’m going to fiddle with the ball valves to see if I can get at least 300 gallons/hour which will match the fish tank size.

I have a question for anyone who stumbles across this thread.

Since I currently have just 2 50gallon growbeds, my ratio for growbeds:fish tank is 1:3 (fish tank is 300 gallons). To get this to a 1:1 ratio, I will need to add 4 more 50gallon growbeds (or the equivalent of 4 growbeds in 1 larger growbed).

I would like to stock my fish a little heavier than a 1:1 ratio will support (as they grow out that is) but I'm having a little trouble figuring out how many fish to start with for my 1:3 ratio that I have now.

I would like to get to a 2:1 ratio at some point since I do have the room for 12 50gallon growbeds.

I'm planning on moving my fish tank into the storage building in which the greenhouse is connected to but I need to get another tank first to move the water to from the existing fish tank. My issue then is once I have 2 of the 300gallon tanks, would I need to add MORE growbeds (for a total of 24????).

Would it make sense to add more sump tank capacity, larger pump, and larger SLO to feed 6 growbeds per tank (keeping it at 1:1 for each fish tank)? My concern is that I'm not going to get enough water flow through 6 growbeds to turn the fish tank water over each hour unless I increase the pump flow and install a larger SLO.

Any thoughts from smarter people than myself?

If your system is already cycled, i would estimate maximum capacity of about 15 lbs of fish for 100 gallons of media . I am using 6 gallons of media per 1 lb of fish. Some people will use different numbers in their conversions. There's a lot of felxibility and "depends" but always start out conservative you wont regret it.

Bcotton's estimate for fish stocking should work. Keep in mind he's basing his on the fact that this is a new system and he's trying to give you some leeway. Here are a couple of other ways of estimating your fish stocking.

http://www.backyardaquaponics.com/forum/viewtopic.php?f=12&t=6646

TCL's first post there is what I wanted you to see.

I'm not sure where he got this but Guitarwes also had an interesting stocking guideline (I'll give it to you but I haven't checked it out yet) -

Came from this thread - http://www.backyardaquaponics.com/forum/viewtopic.php?f=2&t=21701



Adding another tank only requires more growbeds if you are also adding more fish. The focus should be on balancing the filtration with the number of lbs of fish you intend to have when they are fully grown. Hope that makes sense.

Cheers

That is not what i meant at all. As i said, with only 100 gallons of media, he should be targeting about 15 lbs of fish maximum. This is assuming the system is already cycled.


Later on he can add more than 15 lbs of fish and have no immediate problems.. The ammonium and nitrites will stay down, but then there's going to be a new thread about he needs a settling tank and a radial flow filter because fish solids are building up his grow beds..

People can go that route if they do aquaponics for the fish and primary purpose of the plants is to keep the fish happy.. it isnt wrong. But that's not how this system is currently designed and solids breakdown (mineralization) in the grow beds is less waste.

I'm almost certain I got this information from a blog on The Earthan Group's webpage.
Believe me, I wouldn't have written all that down in depth if it didn't come from a reputable source.

1 cubic foot = ~7.5 gallons

so my rough estimate/rule of thumb of 1lb of fish per 6 gallons of grow beds converts to

1.125 lbs of fish per cubic foot of grow bed.. right in the middle of that range you posted.

Since adding the goldfish (22 added, 5 died within 2 days though), my ph has dropped from 7.2 to around 6.0 in just a couple days. Nothing else has changed. I tested this morning with the following as the results:

PH - 6.0
Ammonia - 0ppm
Nitrite - 5ppm
Nitrate - 0ppm

Does anyone know if the shell grit from the feed supply stores (the kind used for chickens) will work as a ph up buffer? Any other suggestions? I'm still cycling so as long as the plants and fish are doing okay I may not worry about it. I did a 1/4 water change this morning but haven't tested again for the PH. I will do it again tonight to see where I'm at. BTW, the tap water PH is 7.4.

to buffer pH up alternate lime and potassium hydroxide

My apologies Brian

PH is 6.8 now, .5ppm Ammonia, 0 nitrites, and 5ppm nitrates. Haven't lost any additional goldfish yet but have had 1 get sucked up the SLO and deposited into the growbed. Alas, the ants got to him and were in the process of eating the body.

i also have cabbage worms eating up my cabbage leaves. I can't seem to kill them by hand though because I have squished all of the little worms on the back of the leaves but the next day there are more. I've even wiped the leaves with a wet paper towel to make sure i get all of them and any eggs. They still show up the next day. Weird thing is that 2 of the 6 plants have not been affected by the cabbage worms. I'm not too concerned since it is really too hot for the cabbage anyway.

Everything seems to be growing albeit slowly. Still in the cycling stage so it's all good...

Use Dipel for the cabbage worms. Lightly dust the leaves. It's safe for AP, but don't cake it on. Reapply after it rains or dews really heavy.

system is cycled. 0 ammonia, 0 nitrite, 20ppm nitrate, ph 7.2 for almost 2 weeks now. fish doing well. tomato plants have tomatoes on them. basil, thyme, peppers, and eggplant doing well. although the growth has slowed down for the eggplant and peppers, the cabbage plants have doubled in size and are starting to form heads. i thought they would be dead by now but they have started growing again in the last week.