Noob in Lyons, CO

[Ben Rodman]

Hi all,

     Excited to learn about AP! I'm displaced from our home at the moment (board can't recognize the zip code for my actual home in Lyons so I called it Longmont), but have been inhaling all the info I can garner and hoping to learn from the collective. I tend towards all thing biological, DIY, plumbing, etc and pretty much teach myself things for fun. Much better than watching TV in my opinion! I'm a pretty mental-level indoor & outdoor gardener, beekeeper, and brewer who also fishes and hunts, so aquaponics feels like a perfect next step! PVC plus fish plus gardening and microbes? Bring it ON!

Things I need to figure out include the possibility of doing this year-round in a greenhouse in our climate, especially how to cool in the summer. Our sun is SO intense that the solar gain cooks anything with solar gain. Anyone use something like a double-walled polycarbonate greenhouse in CO? I don't have a ton of money (especially post-disaster) so a whiz-bang sweet ventilated custom greenhouse has to be a dream deferred... more like Harbor Freight prefab one if it can me made tenable for the setup. Indoor might be possible, but cooling in summer in our shed (especially once HIDs are accounted for) will again be the issue. Love to hear data points/setups from folks in the Front Range.

First question: can a tank be started up (I understand cycling etc) at much less than recommended fish density? For example a 300 gallon stock tank with an eventual 16# of fish in it, way more than 10 gals/fish? I would do this with an eventual eye towards more grow footage as the system (and confidence) grows, but starting with the larger tank would prevent having to size up later.

Possible?

[Alex Veidel]

Yes, you can cycle with less fish than normal. During cycling, you want to keep your ammonia levels at 4ppm. If your fish can't get them up to that level, you can always add some ammonia.

The recommended stocking density is a general guideline for what fish are comfortable with. If you add more than 1lb of fish per 5-10 gallons of water, they might get a little stressed, but you can always go with less.

[Ben Rodman]

Thank you Alex! That's interesting about supplemental ammonia to feed more plants than the fish would sustain. Assuming one just used few enough plants to balance with the fish waste production, what other considerations would an established, over-volume system have for say a year or more? 

I'm operating on an assumption I should check: that "cycling" refers to the building of a micro-organism population (and the system as a whole) balanced with the inputs from the fish, as opposed to cycling being the ongoing maintenance of that system once established. The homeostasis of the system if you will. Correct?

[Alex Veidel]

Yep, that's correct. And more specifically, the term cycling mostly focuses on establishing the nitrogen cycle (ammonia to nitrite to nitrate). There are other microbes than nitrifying bacteria that play important roles in an aquaponic system as well. I think the nitrogen cycle is focused on mainly because that's the life or death issue for the fish. Since fish secrete waste in the form of ammonia, it needs to be taken care of or they die. If your focus is on fish, then the nitrogen cycle seems to be the main concern.

Hmm, other implications of using more water volume than you need? More water volume would make for a more stable system in regards to pH. On the other side, you would need more material to change your pH if you needed to make an adjustment. Keeping your water cooler would also be a little easier with a higher water volume.

Ben Rodman said:

Thank you Alex! That's interesting about supplemental ammonia to feed more plants than the fish would sustain. Assuming one just used few enough plants to balance with the fish waste production, what other considerations would an established, over-volume system have for say a year or more? 

I'm operating on an assumption I should check: that "cycling" refers to the building of a micro-organism population (and the system as a whole) balanced with the inputs from the fish, as opposed to cycling being the ongoing maintenance of that system once established. The homeostasis of the system if you will. Correct?

[Ben Rodman]

Cool could be good. Our water here is incredibly soft (just this side of distilled) which is great; the pH is easy to adjust. Thank you Alex, that informs my planning!!