Feedback on planned system design?

[Daniel]

Hi all -

New to the community here and wanted to run my system plan by you experts for feedback before I jump into the world of aquaponics. I've just finished reading Sylvia's book which I thought did an excellent job of distilling the vast amount information about aquaponics onto the printed page. However, I'd like to avoid as many rookie mistakes as I can - so I'll appreciate any feedback on my plan that you can give me.

 

I already have access to an IBC tote and a number of 55 gallon drums. I also already have a 10'x12' greenhouse to install my system into. The greenhouse is not heated, and only has a single sheet of plastic covering, so I'm still evaluating my options for upgrading my greenhouse into something I can heat, or shutting the aquaponic system down for the few cold months here. (I'm in Memphis, TN so Dec 1 - March is likely too cold to grow most plants inside my current greenhouse).

 

My planned system is to use the IBC tote as my fish tank with the top 12 inches cut off for a media based grow bed. I plan to use the CHOP system with a 55 gal drum as a sump tank, and another 55 gal drum cut lengthways for two additional media grow beds.

 

My concern here is that I have not calculated yet whether one 55 gal drum is a large enough sump tank, or if I need to use two drums piped together to hold the volume of water required for my growbeds. I'd like to use autosyphons on each grow bed in order to leave the pump running continously. I thought to reduce the max water burden on the sump tank I could have the IBC tote grow bed overflow to the two 55 gal drum grow beds so the 3 beds are never all empty at the exact same time. Would this create issues for the 2 growbeds filling up too quickly? Perhaps I'll end up creating more issues than I'm solving by trying to simplify the sump tank into 1 drum?

 

I'm also planning on burying the sump tank (the 55 gal drum on its side), and partially burying the IBC tote (fish tank) in order to help keep constant temp year round. Not sure yet how far I can bury the fish tank, since I'll need gravity to feed the grow beds below the top of the tank.

 

I'm not a very good sketch artist or I'd upload a picture of my planned system. Let me know if you need any clarifications before offering advice, otherwise I'll appreciate any pointers!!

[Kevin Gorham]

Its hard to give advice without visual aids, but I'll try to help. Have you heard of google sketch up? Its a free program from Google that is simple to use and allows those of us who are artistically challenged to make good 3D renderings. 

You could use your IBC tote as your sump, and pump up to your grow bed, and then have gravity feed back into the fish tanks.

[TCLynx]

Consider cutting the barrel for the grow beds in half around the middle to make two round beds, cutting the long ways requires you to build a cradle for them to keep them from bowing and it also makes getting the siphons balanced a bit more difficult.

A single 55 gallon drum as sump tank will be cutting it really close on sump tank volume depending on how deep you make the IBC grow bed, especially if it is on it's side instead of vertical.

Before you bury things in the ground for constant temperatures, think about your desired fish and your ground temperatures.  If you want to grow tilapia, I expect your ground temperature will be too cool and will simply sap heat from the system requiring you to heat it even in warm seasons just to get much growth from the fish.  But perhaps trout would be an option?  Provided you can open up the greenhouse to keep it from getting too hot in the summer.  Though I would probably want more filtration for trout.  Catfish get big for a single IBC cut off as a fish tank so bluegill would probably be your best edible fish choice that could handle the heat and at least survive the old with the system running at a minimal level through winter (as long as you can keep it from icing over and make sure the water cools down gradually in fall and warms up slowly in spring.)

I would probably recommend getting some more IBC's if you can.  Use a full one as fish tank and then cut two in half as grow beds and the 4th sunk into the ground just a bit over half way as sump tank (low enough that you can place one of the grow beds on top but try to leave a gap somehow so you can access the pump.).  Hum, now this design is goind to be an incredibly tight fit into that greenhouse though with only a narrow (probably just over 2' wide) walkway down the center and three beds on one side and the fish tank and one bed and the sump tank on the other.

[Daniel]

APguy - I have downloaded sketchup in order to look at some of the beautiful sketches provided by the backyardaquaponics.com folks. I haven't yet decided if it is worth my time to sketch out my system plan instead of going with the plan in my head. I'd like to keep the IBC tote for my fish tank in order to grow more fish, but perhaps I will need a couple of drums piped together to get the volume needed.

 

TC - I had seen some system pictures with barrels cut in the middle instead of lengthways, but I didn't understand why because of the surface area for growing that you lose. I was planning on making a cradle to hold the barrels, but did not consider the siphons could be an issue in this setup. Is it too difficult to get them to kick on/off due to the irregular bed depth, or something else?

Also considered the fact water temps could get too cold with heat transfer to the ground, but am assuming this is better than having water too warm. With temps over 100 this week in Memphis, I am worried about the water temps in the middle of summer. The rest of the year I may need to heat, either a black tube run out into the sun and back for solar heat, or aquarium heaters during the winter. Wouldn't this be better than having water get too hot for a month during the summer? Is this not an issue in Florida also? Perhaps just going with bluegill as you suggest would eliminate the issue either way - I don't have a need for any particular species of fish, as long as they taste good ;-) I saw some forum threads where people were having large percentages of bluegill die off while trying to transfer into an aquaponic system, are these still a good choice for a begginer like myself or should I focus on optimizing the water temp for tilapia so I have an easy fish to start with?

Finally, I will check into whether I can obtain more IBC totes at a reasonable price. I was trying to keep costs down by using what I have available already, but don't really want to setup a system that is more trouble to fix later than it's worth...

 

Thanks again for the feedback and keep it coming :-) I plan to spend some time on July 4th to at least start building my system, so I'm trying to nail down at least the basic design in the next couple of days.

[Kevin Gorham]

You can still use the IBC as your sump tank and your fish tank, they are not mutually exclusive. You needn't have an extra tank for the sump and then pump up to a fish tank, when you can use your IBC as your fish tank and your sump, and pump to your grow bed and then allow gravity to feed it all the way back to your fish tank.

[Daniel]

Oh - got it. If I did this, the fish tank water level would fluctuate, but it does make for a simpler setup. I suppose I could position the 55 gal sump tank level with the fish tank, and connect them to keep the water level the same in each. This could reduce the water level from fluctuating as much?

I was planning the sump tank to keep the fish tank a constant hight (as this seems to be best practice); do you know how much can water levels change in the fish tank without stressing the fish?

[TCLynx]

If you are not going to stock the system heavily and as long as you don't go beyond a 1:1 ration (as in the grow bed volume is equal to the fish tank volume) you can go with a simple system of IBC fish tank (probably sunk in the ground a little just so the grow beds don't have to be 5' off the ground in order to drain back to the fish tank) and a bunch of barrel halves as grow beds.

That means if you only filled the IBC to like 200 gallons give or take a little, you could then have 4 barrels worth of grow beds (that would be 8 barrel halves.)

Square footage of grow bed surface isn't everything unless you are growing all tiny plants.  Big bushy plants can hang out over the edge of small grow beds to give you the same plant mass in deeper beds so the decision of which way to lay out the barrels becomes much more about how much you want to do to support them and how much of a challenge are you willing to accept in getting the siphons to balance.

I know people who have gotten siphons to work in 1/2 barrels cut the long way.

I personally have never managed to get them to balance though I was usually trying with almost no fall under them to allow the siphons to work well.  I have had a barrel cut round the middle working as a grow bed with a loop siphons for 5 years now.  It is growing aloe like no bodies business.

[TCLynx]

Oh, and I would probably say go for the bluegill or if you want something hardier for your first year, get some nice goldfish as they will survive the cold and the heat better than most everything else (though they don't usually make good eating.)  Just don't get the cheapest feeder goldfish as they are often sickly anyway.

As for bluegill, if people are catching them from wild ponds and having trouble getting them to survive moving into a tank, don't let that mess up your decision.  Get some fingerlings from a supplier that sells fish for stocking farm ponds.  Salt the system to between 3-4 ppt when you go to introduce them and then feed sparingly till the system settles in  (I would fishless cycle first before getting the fish.)  Bluegill are good eating but they grow at vastly different rates, some will be eating size in a season while others might take two years and still be too small to be worth much more than fertilizing the corn.

[Daniel]

Thank you TC! I'll check into sources for bluegill after I get started on building my system. I'd like to cycle fishless, so I'm afraid it will still be awhile before I have a home for anything...

After considering the points you made above on the design, and after finding a very helpful thread on the BYAP forum which you started for posting diagrams, I have modified my plan. I loosely followed one of the diagrams you linked to on the BYAP thread, and took APguy's advice to make my own sketch. Below is what I came up with; hopefully it is self explanatory, though obviously the plumbing will be a little more complicated depending on exactly how I position everything. I think this solves my sump tank issue, and also avoids having more than 1 auto sipon to complicate the water flow rates. The flood and drain on one of the barrel halves may end up being more of a constant flood since it wil drain only as fast as the pump works and will fill again quickly when the sipon kicks in on the other bed.

Any further thoughts, suggestions or design flaws here?

[James Keller]

Hi Daniel - your setup should be a fun one to have.  I wish I had access to and IBC and a couple barrels like that.  My first thought when looking at your setup is that the SLO drain from the tank goes directly into your first media grow bed.  The drain will remove solids, and be dumping those solids into your media, which could eventually be a pain to clean down the road.  I think you'll either need a filter of some sort (i've seen simple sponges placed under the water flow into the bed) or introducing worms into the bed.  I have an SLO that goes into a homemade biofilter, which has a drain at the bottom that lets me take out most of the solids that comes through the SLO.  

Second, the flood and drain outflow from your media grow bed will cause your "barrel flooded media grow bed" to fluctuate (it won't be constant, based on the diagram at least).  And I was wondering how you were going to take water out of the "barrel media grow bed" with a drain that comes out the bottom?  If you were thinking that the ball valve will adjust that flow correctly, it seems like eventually you'll either see an overflow or a much faster drain than anticipated.  

I would stay away from using the water that flows from your IBC media grow bed to fill both of the barrel grow beds.  Maybe use water from the fish tank to fill all three grow beds, but only use the IBC media grow bed as a fill and drain system, and keep the others as constant height grow beds.  That would alleviate or even eliminate the worry that the sump tank would be too small if all three beds drained via the bell siphon all at the same time.  

This is all based on my limited experience so far, but also incorporates my thoughts on exactly the type of system you've got as my next setup...  Hope this helps, and have fun!

[TCLynx]

James, you bring up some very valid points about the flow into the flooded media bed (the outflow from a siphon will be fast and it will likely over flow an already flooded bed that has only a small drain.)  When you cascade beds in that fashion it can get a bit tricky.  Think of the IBC bed as more like the "flush" tank on a barrel ponics system and I expect you could have that one bed drain to both of the half barrels and have them drain from the bottom to the sump tank if you really want to cascade them.

Jame's other recommendation though to use the two barrels as constant flood and have all beds drain back to the sump  and all beds get fed from fish tank is probably an even better idea since it will allow all beds to get solids from the fish tank and avoid the problem of the single bed getting overloaded with solids prematurely.  Properly stocked and designed systems shouldn't need  "gravel" cleaning but if you go sending all the fish poop to just one small bed and stock the system heavily, that one bed will get clogged.  Constant flow/flood works as long as the beds are getting a good enough flow of well aerated water.

[Daniel]

Thanks for the feedback James.

I'd like to add worms to the first grow bed to deal with the solids. Any particular media I should use/avoid for having worms in this bed?

I'm anticipating the two barrel grow beds to be level with the sump tank so that when the sump tank is full the two barrel grow beds will have a water level equal to the water level in the sump tank. The first grow bed will be piped towards the top of the grow bed, so it cannot drain - it will be a flooded bed which overflows into the next barrel grow bed as soon as the IBC grow bed empties its water. The second barrel grow bed should flood and drain as the water level in the sump tank fluctuates - since the bed will be piped directly into (and level with) the sump tank. It is basically an overflow of the sump tank.

The valves between these two grow beds (& between the sump tank and barrel grow beds) is really just in case I ever need to replace or replumb one of the grow beds. Since these beds are level with the sump tank, I need to make sure I can stop the water from backflowing from the sump tank if I remove the grow bed during a reconfiguration.

Maybe these two barrel grow beds make more sense now?

[TCLynx]

Right but since you are using those two barrel beds as the drain for the siphon flood and drain bed, you won't be able to do anything with them without shutting the whole system down and re-doing the drain from that bed.

You can still have those two barrels coupled with the sump but I would have them get flow from the fish tank instead of the flow from the siphon.  Send the siphon drain back to the sump tank and couple both those beds with the sump if you like but don't have them chain through each other since that set up means if something goes wrong with any element, your hole flow is going to be interrupted while you re-work everything to allow you to bypass the problem in order to fix it. 

I would only use ball valves on the feed from the fish tank to grow bed if you actually have several grow beds and need to balance the flow to them.  If there is only one bed being fed by the flow from the fish tank, you have to adjust the flow to the fish tank so it won't overflow instead of adjusting the flow out of the fish tank.