Backyard Aquaponics
A place to discuss aquaponics

Regardless... production of carbon dioxide by fish respiration isn't a major contributor to carbon dioxide concentration within a greenhouse... as the carbon dioxide released by fish respiration is readily dissolved in water...



It will affect pH though ...

So the relative oxygen and carbon dioxide concentrations with the air in a normal greenhouse... and an aquaponics greenhouse would IMO be essentially the same...

Okay... So if CO2 is that soluble compared to Oxygen, and it affects PH, is there no easy way of keeping your O high and your CO2 low in your water?

Yep... don't put fish in there... and don't let algae grow....

Seriously Gblack.... the interactions between the elements/compounds are a natural and generally counter-balancing system...

In a properly setup AP system, pH may drift over time, but is fairly easily addressed...

The issue of algae is an important one ... as algae consumes oxygen and releases oxygen in a cycle throughout a day... affecting both DO and pH....

This is particularly important in pond based aquaculture, but generally avoided in AP systems by shading the tank....

Gblack, I think you're making too much of what are essentially self balancing, or slow moving, minor impetus natural processes...

I get the slow moving, it-all-works bit. I'm just looking for a better way to build the mousetrap - particularly since I haven't started construction yet

Part of the beauty of AP is that it's not a perfect replica of nature - this looks nothing like growing field crops - yet it arguably works better. I'm just poking around to see what further improvements people might be aware of and to also learn enough to make sure I didn't miss anything serious when I do start building.

There's nothing wrong with that approach Gblack...

I converted a garage to AP greenhouse here in the Mohave desert. I use wax filled automatic solar vents above the sliding glass doors only, in winter. also I open doors in the summer for cooling and circulation. No fans. In winter I do get lots of humidity and condensation on the glass. The plants are thriving as are the bluegill and goldfish.

Would you mind posting details of your conversion of the garage? I've had some thoughts about trying to convert a garage as well.

Thanks!

I simply removed the siding to the south and raised a strongback in place of the studs. and fitted used sliding glass doors in place with studs to each side. The interior and ceiling was insulated with 3.5 in. fiberglass and sheetrocked with "green" or damp proof gypsum and painted white. The 18 in. overhang precludes much of the summer sun from getting deep into the space so am reroofing and adding skylights. I ended up with 12ftx30 ft interior space....enouth for two 4x12 grow beds, two 100 gal sumps, two 150 gal FT and one 275 gal FT. The FT without a grow bed does have two 6"x10ft hydro trays but is drained by 50% to water the fruit trees daily. Sliding doors allow placing the grow bed flush to the outside wall and still have access to the plants as well as summer venting.

Your greenhouse won't need the fans for air circulation, if we go by the 50m rule. If you have a 50m greenhouse of 500sqft area, then the it would be 165 ft long, and 3ft wide (495 sq ft). A more reasonable size would be 20'X25', and that's pretty much a large family room size. If you are doing this as a sunroom extension of your house, then you can use do some air exchange, in Utah, you shouldn't have any problems with too much moisture, and it may give you some additional cooling in the summer.

I don't think you need to worry too much about CO2 vs O2. The plants will use what you provide, the CO2 will build up some at night, go down during the day. You will probably want to discourage algae for two reasons: 1 - it will use up valuable nutrients that would otherwise feed your plants, 2- it will bounce the pH all over, and stress your fish.

Since you mentioned lakes, I assume you're in the Utah Valley or the Salt Lake Valley? (probably Utah, since people in Salt Lake Valley often forget about Utah Lake). I think that during the summer, you will probably want to ventilate. If you add some sort of fountain or spray, you may be able to take the place of the swamp cooler, and taking air in, cooling it in the GH, then letting it into the house would probably work really well. During the winter, you would want to have some really good insulation in the GH (double or triple glazing), and you should be able to use the sun for some solar gain, and again, the moisture to humidify your house should be really enjoyable.

As to design considerations, you may want to have the FT under the walkway, and have a timer based system. That should make the real estate more profitable. I know someone was planning on walkways with movable grates. Otherwise, you could do a CHIFT PIST with the Sump being under the walkway.... Just an idea.

CHIFT PIST is really a good way to go (so long as the water from the fish tank goes to the grow beds before dropping to the sump tank) cause it means the pump stays cleaner.

Only issue I will mention about putting a sump or fish tank under a walkway is the debris/dirt/sand whatnot that can fall from shoes into the tank. This might not be a really big problem but it can become a vector for contaminants to get into the system off of shoes that might have walked through some bad stuff somewhere or other.

In truth, I'm in Utah valley moving to Salt Lake Valley - it's the south end of the valley though, so I'll still be fairly close to Lake Utah. Too bad I don't dare eat anything I catch in there....

Given the popularity of swap coolers around here (I hate the things) I had been thinking of some sort of evaporation based cooling solution to help cool it in the summer, and have been looking for every possible way to help with heating during the winter (I figure by adding it on to the house it can at least take advantage of some of that heat that would typically be lost through the wall - also the close proximity to the house makes it easier to get a gas line to it for a heater of it's own.

I don't quite get the idea of putting something under the "walkway". I had envisioned a concrete pad behind the house. I suppose I could leave a hole in the pad or something to bury a tank, but then I'd be concerned about possible maintenance issues if I needed good access to the tank for some reason (that and if I do anything permanent to hurt resale value my wife will insure I'm the one swimming with the fishies...)

I am unsure whether it has been mentioned but CO2 is more soluble than O2 in water. You do not want elevated levels of CO2 where aeration for the FT is occuring. Your main concern would be ensuring adequate supply of O2 for the fish and bacteria.

And SpiritRancho mentioned using used sliding glass doors. Be careful, if buying new doors, not to get low-E as that really cuts down on the light that will get to your plants. This is apocryphal info, so just take this as a possibility, not a fact.....