Newbie Questions

[Spooky__Fish]

I have 4 indoor ponds used to growout ornamental Cichlids. The ponds are 500-1,000 gallons, and I would like to add aquaponic systems to them in order to maintain better water quality and minimize/eliminate water changes. The vegetable crops are a big added bonus, but not the main intent.

My hatchery is designed for simplicity, low labor, reliability and really low cost. I would like to approach aquaponics the same way.

I'm thinking that the 4 separate ponds should all have there own independent aquaponic system. I'm cogitating using barrels cut in half with pea gravel and a bell siphon fed directly by pumps submerged in the ponds and lit with fluorescents.

Is pea gravel my best bang for the buck? I guess a masonry supply place the best source?

I got barrels but they are white/clear, is algae going to be a problem, benefit or non-issue?

Do the center of the barrels need to be supported? If so, what is recommended? It looked like Badflsh was using zip ties?

I found the stainless fluorescent fixtures that Badflash recommended, but they take two 32watt T8 bulbs. That don't seem like enough light to me, but I'm a total newbie and know nothing. Can 1 fixture supply sufficient light for 1 barrel?

The ponds get filled with 3/4" fish which grow out to 2". Obviously the nitrate production changes greatly as they grow. I'm wondering how you calculate how many barrels you would need per pond, and thinking the number changes over time?

I'm looking to do crops that don't grow too tall and grow fast. I'm thinking mostly mesclun salad mix, cilantro etc. My African Cichlids and ancistrus cats get fed zucchini and green beans occasionally. I don't want to grow those two plants, but would like to grow something to feed the fish. Any suggestions? Any veggie they will eat and I can make sink is a big +

Any comments and suggestions are much appreciated!

[keith_r]

welcome aboard, sounds like a great way to get your feet wet!

i think a separate system for each pond would be the way to go

as far as "pea gravel" - you don't want something "pea" size, maybe a little bigger, like river gravel, and stay away from limestone (you can test your media with vinegar, if it bubbles you don't want it) - landscaping places are a good source as well as home depot type places

white barrels will break down from uv faster than blue/dark, but the dark colored barrels absorb more heat..i use barrels, and am thinking of some kind of "skirt" around them next summer (seams like a long way off, had a foot of snow yesterday) - the barrels need support across the bottoms and sides, google "travis hughey" for a good barrel stand idea

regarding the lights, i've got 3 t8 pairs across 2 growbeds, and have radish, green peppers and salad mix sprouting, other stuff looks ok, i have 2 pair with "cool" lights, 1 with "warm"

if you have a good ratio of growbeds to pond volume (1:1 is good, 2:1 is better, thats growbed to fishtank) you might want to raise the beds up (so they are easy to sow and harvest) and use sumps if you go with a higher volume of growbed so that you don't drain your ponds when cycling water, or look into "sider valves" and fill growbeds in sequence, with the right filtration, you don't really need to do water changes,, aother way to look at growbed volume is 25lbs of "grown out" fish to 100 gallons of filtration/media, that'not a "law" by any means, but a good rule of thumb.

good luck and take lots of pics

[badflash]

I get my barrels for free from the local car wash. Most of the stuff they use is safe as long as you wash it out well. I split them the long way and use a big zip tie to hold the middle from expanding.

[Spooky__Fish]

Thanks for the replies.
I got 2 serious issues I am working on now.

1) I raise African Cichlids, which come from hard Alkaline water. My water here is around 8.5, which is great for the fish.
Best I can tell, if I want to grow anything other than algae, I need to lower the PH on the ponds. The fish can probably deal with the conditions, but now I would have different water chemistry between the ponds and the 150 tanks. The fry will have to be acclimated before introduction to the ponds, and the grown-out fish acclimated back to the tanks from the ponds. To adjust PH, should I be thinking about a buffer or just an acid safe for the fish and plants?

2) My biometrics are vastly different from raising food fish. This may make keeping an AP system in balance very challenging.
A) My target density is 4 fish per gallon. At the introduction phase, this translates to 0.002 Lbs/gallon and 0.035 Lbs/gallon at harvest.
B)From when I introduce fry to the ponds, my time to market is only 3-4 months.

I'm thinking, my systems need to be plumbed so I can remove barrels from a harvested pond (soon to be filled with fry) and add them to the other, more advanced ponds.

I'm also thinking, I need a lot less grow bed space than you folks!

[badflash]

Don't over think it. The stock SS fixtures from walmart are fine as are daylight bulb. Buy some back up ballasts as they go after about a year. Young plants pull out more nitrates than mature ones, so keep harvesting. With a volume as large as yours, just sample for nitrates and adjust when needed. You can add fast growing water plants like najas if thing get out of hand, just light the tank.

Do a little digging, lots of greens do fine with high pH, and lots of cichlids do fine with a lower pH. Don't fight your water. Match your plants to what you have. Najas loves cichlid water, but you can't (or I don't) eat it. I'm sure other plants love high pH water too. I've just never dug in and figured out what.

[urbanfarmer]

Basically, in an aquaponic system you have 3 groups of living organisms to consider. The fish, the plants, and the bacteria. Since you are going with a gravel grow bed, the invertebrates (such as worms) that help break down solids and sludge are also important, but seem to thrive all on their own.

In my opinion, pH is the single most important "number" in an AP system. As you probably know, unionized ammonia is what really hurts fish and not the TAN (total ammonium nitrogen). To give you an idea from your pH of 8.5 compared to a pH of 5.5, you will have ONE THOUSAND (x1000) times more unionized ammonia in your water than if it was 5.5!!! I am less familiar with specifics in aquaculture. Is there a benefit to the high pH of the water for the fish? If so, that is something to consider.

With that said, I am not suggesting you try to keep it at 5.5, but that a lower pH could greatly benefit the water quality of the fish as well as the plants. In general, a pH of 8 does not adversely affect the harvest potential of some veggies (although for herbs, leafy greens, and early harvest plants it may). Also, a higher pH is better for the bacteria in the system... but as with all aquaponic systems, finding the right balance for your specific environmental conditions is the True answer. As a rule of thumb, we suggest a pH somewhere between 5.5 to 8.0 with 6.5 to 7.0 being generally safer for most people, but the latter range may not provide the optimal performance.

Duckweed is a popular plant to grow and feed to tilapia. The protein content is supposedly ideal for them. Milwaukee's Growing Power uses watercress (I think) and he seems pretty happy with it as a filter for the fish. If I'm not mistaken, his system is optimized for the fish as opposed to the plants or an equal balance for both.

OH, and Home Depot has $10 shop lights (with hanging chains) that take 32 or 40 Watt T8 bulbs. The bulbs are $1 and 4100K color with around 3200 Lumens (if I recall). The metal on the shop light casing is thin enough to drill sheet metal screws through to build a fixture with as many lights as you need. In my experience, they pump out quite enough light. I grew peppers in my indoor system, and I got better results than outside (due to other factors than the light).

[urbanfarmer]

I just stumbled across this. It could give you some ideas also:

THE FEEDING PREFERENCES OF TILAPIA AUREA FOR FIVE AQUATIC PLANTS
http://digital.library.okstate.edu/o...v64/p14_16.pdf

[Spooky__Fish]

Thanks for all the info.
I wanna stay away from aquatic plants and lighting the ponds.
I think I'm going to setup a single barrel as a test to see what will grow. I already got lettuce seeds started and a barrel ready to be cut!

Is there a benefit to the high pH of the water for the fish?

The water they come from has a PH of 7.7 to 8.6. Besides that fact, I know of no benefit they receive from those conditions, or any reason they won't thrive at a lower PH. However, fighting my water as Jack mentioned, is something I'd really like to avoid.

[jcx]

This may be helpful.

This chart shows your P.H levels effect on the availability of nutrients.
I don't grow a very wide verity of plants, I would guess there is something that can live in 8ish.

[jcx]

Also found some links for plants that will grow in alkaline soil. Looks like there is not too much in the veggie department, maybe something will work for ya.

http://www.ehow.com/list_5914782_plants ... oils_.html

http://www.thegardenhelper.com/alkalineplants.html