understanding the economics

[Lance Rose]

I am trying to keep books on my setup so that I can gauge how to expand without robbing a bank.

I hope to kickoff a discussion about relative cost and economies of scale. 

For my current setup, I have "free-sourced" just about everything but the fish and plants. But now I am running into some stuff I did not account for, which will cost me a little. For example, the testing kits.

I have water in 2 55 gallon barrels. So I guess I have about 100 gallons of water. I have 50 coppernose bluegills. The growbed is 1 55 gallon blue barrel split in half.

My startup cost were about $50. $25 for plants and $25 for fish. I also had a little plumbing couplings to buy.

If I had paid retail for all the stuff,

Barrels (?) I am seeing $30 each on a couple of websites = ($90).

Frame wood ($30)

PVC (10' 1", 10' 3/4") plus couplings, glue ($30)

Rocks (this one is hard) If you buy bags at Loews/HD (15 X $3 = ~$45), Or $1 per bucket at a local aggregate seller (~$15). 

Pump, ($45 at Loews/HD)

Around $200. Sound right?

So startup will cost between $0 (catch the fish from pond and get plants from other source) to $250

In a 3'X2' grow bed, I think I can get some strawberries, Okra and a couple of tomatoes. I might get $20 worth of produce.  If I manage to kill 0 fish, I will get 50 good sized bluegills which have a value of (what?) If I buy fish at walmart, it is $4-$5 for a package of 2. So for eazy math, I will say $2 per fish = $100.

So my output value is in a range of $0 (all die) to $150 if everything goes right.

My ongoing cost are food, electricity, water and testing.

Food so far is a bag of commercial feed, I got that for $15. I expect to use a lot more in the future, but right now, not so much. 

Electricity is ?. I have no way of measuring the actual usage. I'm not sure how to convert watts or amps to actual unit of energy I get charged for.

Water. I have a well, so my water use is basically electricity. Plus I am adding a little water every other day. This will be more in the summer. But again, I dont know how much this cost me.

Testing (~$15/kit). I am testing once week for 1 week so far. I'm not sure how long this kit last. I'm guessing 2 months.

So if a bag of food and a test kit cost me ~$20/month.

Am I missing anything? I am trying to make an Excel spreadsheet to cover my cost as I go.

[Cliff Jagger]

I'm not sure why your ph is climbing...what have you introduced to the system lately ?

Strawberry is tubes - distance apart would depend on your water flow.  6" apart is what I use for my plants and I also aerate the water.  My tubes are 20' long.
 
Lance Rose said:

I measured this morning and it is at PH of 6.5 (Mardel) 6.8 (API). Does that seem like a lot of climb in a few days?

I finally got a full test kit and will start the full testing daily tonight.

I also got a handful of strawberries this morning. And there are a pink bunch that will turn red in the next few days. Base on what I spent, that is about $6 a strawberry! But the cost is coming down every day. 

For a proof of concept hobby tank, I think that is pretty good!

Back to the original idea of the post, What are some representative numbers from some other folks? I drew up a plan for a ~200 gallon (10X3X1 = 30 cu ft * 7.5 = 225 gal) in ground fish tank covered by a ~200 gal grow bed with a heat pump built in to keep the water cool in the summer and warm in the winter. The cost I estimate, using all commercial pricing (I usually free source stuff) would be about $500. I estimate my actual cost to be around $150-$200. Mostly for a couple of pumps. 

How much strawberries can I grow in a 30 cu ft bed? 

What about in six 10' long 3" PVC pipes? How far apart can I put the plants in a PVC tube?

I have included a BMP of my bed idea and a Excel spreadsheet of my estimates for commercial priced. 

Again, Thanks for all the input, it is really interesting and greatly appreciated.

[Lance Rose]

I just took out fish. Went from 50 3" fish to 15. Plus it rained on and off all night. I will test tonight and see where I'm at.

Cliff Jagger said:

I'm not sure why your ph is climbing...what have you introduced to the system lately ?

Strawberry is tubes - distance apart would depend on your water flow.  6" apart is what I use for my plants and I also aerate the water.  My tubes are 20' long.
 
Lance Rose said:

I measured this morning and it is at PH of 6.5 (Mardel) 6.8 (API). Does that seem like a lot of climb in a few days?

I finally got a full test kit and will start the full testing daily tonight.

I also got a handful of strawberries this morning. And there are a pink bunch that will turn red in the next few days. Base on what I spent, that is about $6 a strawberry! But the cost is coming down every day. 

For a proof of concept hobby tank, I think that is pretty good!

Back to the original idea of the post, What are some representative numbers from some other folks? I drew up a plan for a ~200 gallon (10X3X1 = 30 cu ft * 7.5 = 225 gal) in ground fish tank covered by a ~200 gal grow bed with a heat pump built in to keep the water cool in the summer and warm in the winter. The cost I estimate, using all commercial pricing (I usually free source stuff) would be about $500. I estimate my actual cost to be around $150-$200. Mostly for a couple of pumps. 

How much strawberries can I grow in a 30 cu ft bed? 

What about in six 10' long 3" PVC pipes? How far apart can I put the plants in a PVC tube?

I have included a BMP of my bed idea and a Excel spreadsheet of my estimates for commercial priced. 

Again, Thanks for all the input, it is really interesting and greatly appreciated.

[TCLynx]

There are plenty of things that can cause pH to shift.  The nitrogen cycle tends to cause pH to drop.  Algae can cause pH to swing based on time of day.

[Lance Rose]

I am going to check it again tonite.

TCLynx said:

There are plenty of things that can cause pH to shift.  The nitrogen cycle tends to cause pH to drop.  Algae can cause pH to swing based on time of day.

[Lance Rose]

Tonite PH = 6.8. 

[Cliff Jagger]

just add some distilled white vinegar  1/2 cup to 200 gallons it will bring it right down.

[TCLynx]

I'd recommend leaving the pH alone!!!!!  a pH of 6.8 is just fine!!!!!  Actually just about perfect!  Adding acid to adjust pH is not necessarily a good thing, especially in a new system that is just trying to cycle up.

[Chris Carr]

+1 for leaving it alone at 6.8

[Vlad Jovanovic]

+1 for sure.

[M D Fowler]

harbor freight is cheaper then loews on pumps and they do have a solar one, but i think this is what you might want

http://www.harborfreight.com/264-gph-submersible-fountain-pump-6839...

 

also i got 1/2 ton of pea gravel cheaper then the bags, you could fill about 4 barrels with that

[TCLynx]

Those little 264 gph pumps are a bit small for all but the tiniest systems.

As far as their solar fountain pumps, don't waste your money!!!!  I got two different ones and neither of them continued working after about two months and they actually only circulate water while full sun is hitting the solar panel and even at full force of water, they wouldn't keep up with much more than a beta bowl.  And I believe at least one of those pumps actually says not to use it in a system with fish.

[Lance Rose]

I have not changed anything. All seems to be well. I got the API master kit and (I don't have the numbers with me), but they are all in the good range. I think pulling the number of fish down probably helped out. It all looks good to me right now.

I have start making drawings of the system for next year. I am trying to make a complete plan from about November until the end of summer.

My goal (as always) is to see how much I can free source and not cut corners.

I plan to have two 3' X 10' X 1' (30 cu ft, 225 gals) of grow beds with a 200 gallon tank in the ground underneath. Plus two 55 gallon barrels buried for cooling. This will give me a total water volume of about 300 gals.

The beds and the tank will be wooden lined with 6 mil plastic liner (need input here).

I plan to move water with two 300 gph at the head height pumps. 

I plan to have a row of tomatoes, strawberries and probably some complimentry herbs.

The fish will be a couple of catfish, and coppernose bluegill (I am still working out the exact numbers based on how things go this year). 

My hope is to spend less than $200 and produce a "crop" worth about that much.

 

I am working on a deal with a local farmers market that will "sponsor" my project for billing on any news stories I can get printed in local media (newspapers and internet). 

I will be posting an online diary of the build with complete cost breakdowns as I go. Any ideas or other support would be greatly appreciated.

If I can get other similar projects to also document their processes, we can build an experience database. 

Really, in effect, that's what these forums are right now. They have been a huge research benefit to me.