Backyard Aquaponics
A place to discuss aquaponics

Currently in the greenhouse we use three different techniques for keeping it cool during the summer:

* Venting
* Shadecloth
* Misting (combined with the venting)

With an aquaponics setup in the greenhouse, any ideas on if we'd continue to use the misting?

We start dismantling this weekend, and I'm trying to figure out what all gets removed and what gets left.

GB and FT evap will keep it cool just like the misting!IMHO

The misting shouldn't be a problem I think. I have one set up in my green house but have yet to use it. You use mains water for your misters? You already have the green house growing experience so I'm not so sure much would change by just adding fish into the mix.

Utilising the misters may depend somewhat on what plants you're growing...

With a large amount of water continually circulating through the growbeds and some evaporative effect contributing to humidty in a greenhouse environment... you may find that using the misters contributes too much humidity for some plant types... particualrly things like cucumbers, zucchinis etc

You might need the added moisture during the end of June through beginning of September with the low humidity that you have during that period. It all depends on what you grow. With your mild temps during summer, I would think shadecloth and ventilating fans would be enough to keep it cool enough for most plants. The fish you choose might need something cooler during summer.

It seems your humidity and temps are disproportional when one is high the other is low. During your fall and winter humidity is highest then tapers off during the spring to the lowest values during summer. Here in Kansas it is exactly the opposite. High heat with high humidity, when cold very low humidity. That is why I have to add water to my system so much here lately. 200 gallons worth of systems are requiring about 50 gallons of make up water per week at this time. During the summer the 55 gallon system I ran only required topping up with about 5 gallons every other week or so. Being the present system is housed in my basement the humidifier is no longer needed to keep the house from being extremely dry.

I would be more concerned with your winter and heating the greenhouse. How much gain do you get using solar heat when you see the sun rarely during your misty/raining winter? I would be prone to using wood heat to reduce the moisture somewhat during that time of year.

Thanks all. I think I'll be leaving the mister in place. I had wondered if it would create too much humidity when used but since it's already in place and it's out of the way, I'll just leave it - just in case.

Fireplace in the greenhouse... how romantic.

DownRiverDan, how would you go about using wood heat in a greenhouse. I am guessing for winter, I'll have to go to cool weather crops - though the "greenhouse" tomato did fabulous in there this winter. We do have very limited sunlight during the winter... get miserable long spells of gray and rain. And, when the sun shines it gets cold but then could use some kind of solar collector to heat the water.

The buckets of water (current heat sink) are still at about 60 F, however they are closed so not sure what affect circulating in a cool greenhouse will have.

We had a great conversation last night about fish. Tried some tilapia from the local store and then talked about other alternatives. I think we'll be going for a cooler water fish - perhaps yellow perch and or hybrid bass. Anyone grown bass in an AP system?

a good air tight wood stove will put out a lot of very dry heat. Most people around here that use them for heating their homes place a shallow pan of water on top of the wood stove to try and offset the drying effect. If you had a greenhouse tomato do well this winter you might not have much of a temperature problem. What are your air temps currently running in the GH?

How did you find the taste of the tilapia you tried? Where was it raised?

The tilapia I tried from the grocer here was not as tasty as crappie or bass, but was better than catfish. I still feel walleye (Sander vitreous) reigns supreme in taste as far as fresh water fish is concerned. They are a cold water fish that would be tough to grow out due to the fact they only eat fish for the most part (yellow perch, a cousin, is their favorite meal).

The following walleye background info is from http://www.seagrant.umn.edu/aquaculture ... ye_culture
Where they also explain some trials that they ran. Good read and shows that they had high mortality and low food to flesh conversion.

In the wild, walleye feed exclusively on living organisms, such as zooplankton, insects, and other fish. This preference is so strong that many walleye will starve to death before they will eat artificial feed. When farmers try to train walleye to eat artificial feed, mortality rates of 50 to 90 percent are common. This training process is costly and requires a high capital investment, intensive labor, and expensive feeds. Newly hatched fry must be confined to indoor tanks where light, water quality, and feeding can be tightly controlled, and food must be provided constantly for up to one and one-half months. In addition, the feed must be formulated to exacting standards and contain large amounts of protein.

One major source of fry mortality during training is non-inflation of the swim bladder (an organ used to maintain buoyancy) after hatching. This organ must be inflated when fry are very young or they will sink to the bottom of the tank and die. Although the cause of this problem is not yet well understood, it is the subject of much current research. Another major source of mortality is cannibalism. With no natural feed available, fry will eat each other. After hatching, one fry can eat another that is almost equal in size. As they grow older, a larger size difference is required.

If walleye trained to eat artificial feed are stocked in a pond where natural feed is also available, they may switch back to the natural feed. Even when this supply can no longer support them, they may not return to eating the artificial food and their growth may slow.

Because they are carnivores, walleye have a high protein requirement, which typically means feeding costs are relatively high. Research is being done to more precisely determine their nutritional requirements.

Walleye are crepuscular fish. They tend to feed when light levels are low, such as at dawn, dusk, and before rainstorms. In very turbid water, they may be active during the day as well. A layer in their eyes, the tapitum lucitum, gathers light and provides them with excellent night vision. This affinity for low light may be an important consideration when determining feeding regimes and designing walleye culture facilities.

Walleye do have some advantages as a culture species. They tolerate a wide range of physical and chemical conditions. This tolerance is related to their natural environment, which is typically large, semi-turbid waters, where temperature and water quality vary considerably. Although they tolerate temperatures between 4¡C (39¡F) and 30¡C (86¡F), walleye grow best between 20¡C (68¡F) and 23¡C (73¡F). Spawning occurs shortly after ice-out in spring when temperatures are between 7¡C (45¡F) and 9¡C (48¡F). They can withstand dissolved oxygen levels as low as three parts per million (ppm) and have been known to withstand two ppm for extended periods in the lab. This hardiness is important because daily and seasonal changes are common in intensive outdoor culture systems.

Male walleye mature at two to four years, at 280 mm (10.9”) in length, while females mature at three to six years, when they are 350 to 430 mm (13.6” - 16.8”) long. The females spawn in shallow water where oxygen levels are high, and prefer sand, gravel, or rocks as substrate. Group spawning appears to be common. During spawning, milt and eggs are released into the water column, where they fuse and settle to the bottom. On average, 60,000 eggs are released per kilogram of female. The life expectancy of a walleye is five to seven years in southerly, warmer climates and 12 to 15 years in northern areas.

Other possibilities are;
Sauger (Sander canadensis) or even the cross between sauger and walleye- the saugeye would be other very tasty fish for cold water situations.

The tilapia was grown in Ecuador. Interesting flavor... we decided somewhere between trout and catfish. It was okay but not great in my book... I'm not a big fan of catfish. Ironically, we did have walleye with it and some "pan fish", likely bluegill that Tom's daughter and husband flew out to us recently from Wisconson. I much prefer the walleye but from what I've read, not a likely fish to grow out... and your info certainly supports that. A likely candidate would be yellow perch and some other compatible fish.

As for current temps... the greenhouse has been falling to about 37 at night but our nighttime temps the last week have been in the upper teens and I've been running a test as to what it would get to without heat. Whenever it gets that cold here, its very sunny days so daytime temps have been in the 70's. Keep in mind we have a "solar" greenhouse which means insulated east and north walls & a wall of buckets filled with water as a heat sink. Even today, when we had the greenhouse wide open all day and the temp was around 32 outside, it's now 40 inside now that its closed up guessing due to the buckets. The norms have been more around 40 at night and 45-60 in the day, depending on the amount of sunlight.

Sun is defnitely an issue for us in the winter. It's sounding like our growing in the winter will match what the greenhouse has already been growing... "cool season" crops, peas, greenhouse tomatoes. The cucumber and the basil died early on and the peppers were just a bug magnet though they might have been healthy otherwise. I have found the last two winters that root veggies will hold over but don't grow much in the winter. If they are at size by about the first of December, they'll be good. And, amazingly, we've had a few strawberries here and there. I think they would have done better with a consistent supply of water.

Here's the current plan..

We have 1 IBC (275 gal/1070l) that will serve as a fish tank. We will go ahead and bury it about 3 feet/~1m which will leave around a foot/300mm above ground. We will have 3 blue barrel halves up high to grow duckweed, water hyacinth and hopefully some crawfish and/or freshwater shrimp. These will be continuous flow recycling about 1 time per hour.

Then we will have 9 or 10 blue barrel half grow beds with bell siphons draining directly into the fish tank. The goal would be to have these cycle 3-4 times per hour and use pea gravel as the grow media.

We have a 950 gph/3600lph and a 3800 gph/14,385 lph pump at our disposal for the project. Depending on how we plumb, the water will rise between 6-11 feet/1.8-3.3m and then cycle around to the beds. Based on earlier posts, if we used the 3800 gph pump, we would also have water cycling around and back into the fish tank for added aeration as well as running a small fountain and possible a solar heat collector.

Questions:
1. Would we be better off with a 3/4" (17mm) or 1" (25mm) standpipe? We've searched the forum and are still unclear on that one.

2. What kind of steps do folks take when burying a fish tank? Do you insulate it? Do you put a layer of something underneath it? We have some ideas but are curious what has worked best for others when burying tanks.

3. Any thoughts regarding the pumps? Would we be better off using the 950 gph pump? It appears from using some of the calculators this may be a better fit, though would only be able to run the cycling of the beds without the other amenities.

Any other feedback on the proposed system would be much appreciated. What follows is the proposed layout. The only changes are the worm bin will be just that... without a sump.

On questiN 1 I WOULD GO FOR THE 1IN ONE [gives a bit of a buffer
Question 2 when burying its wise to put gal tin on the outside [leave the tank in the cage ] otherwise dirt will eventually collapse it
Questian 3 use the biggest pump and tee off a return line to the fish tank [helps do and keeps the muck stirred up]

I agree with F&F anything less than 1" has been just too damn slow for me. 1" is too slow in some places too, but it's easier to drill a hole bigger than to try to make it smaller, so go with the 1"

Dirt is a great insulator, it's another reason why burying is a good idea.
I placed corro roof sheeting around my buried tanks for the reason F&F suggests, outside pressure, but I have heard some ppl doubt the necessity. It never hurts to plan for the worst though.
If you leave the tank in it's cage, it will have a 200mm pallet underneath for it to sit on, if you have put gal sheeting around the tank, then dirt will take a LONG time to get in there and disturb the bottom.

Again, with the pump, it's easy to restrict the flow, but getting more flow than the pump can handle is difficult. Get a big pump do not restrict the intake of the pump though... As the pump gets older and more clapped out, it may find it difficult to pump the same flow. At this point, just unrestrict it a bit.
It's also great to have a pump that can deliver high flow, as it often dislodges blockages for you.

On lining tanks i have put cool room material around mine acts as an insulator as well [there have been 3 that i recall that have collapsed so far ]also when burying your tank leave an inspection hole somewhere so you can see if theres water building up underneath [ we dont want it to float do we ] theres been a lot of buryied tanks sumps ect float

not to be disagreeable but I would think that the 3800gph pump would be very excessive even with returning 2000 gallons per hour back to the fish tank.(they would not like that me thinks)
Maybe my math is dodgy but you intend to flood 10 beds @ 8 gallons each 4 times per hour = 320 plus about 80 to your three suspended half barrels equals 400 gallons an hour. The additional 550gph extracting the difference needed for pumping to an 11 foot head should allow for the solar collector run, a small fountain and air producing return to tank. Am I missing something or is my brain not up to par this morn?

Just a comment on the flavor of tilapia. I like grocery-store tilapia. I -love- fresh home-raised tilapia. There is a notable improvement in flavor and texture when the fish is fresh and raised in good conditions. I do also like trout and (as I recently discovered) fresh catfish.

JP, would you say the flavor is stronger or milder in your AP grown tilapia?