some basic questions

[Pat James]

I presently am using a vertical hydroponic system in my greenhouse. I have a fairly large swimming pool that I plan to use as an aquaponics system.

I live in northern Louisiana, so I will probably wind up with catfish in the pool. In the interim, I am going to put in some rosy reds which are really a red color variation of fat-head minnows. they are supposed to be omnivorous so maybe they will eat up some of the  algae/leaves/crap that has accumulated in the pool. The catfish can eat them later...

I have been doing my reading, but still see alot of conflicting advice. I know I need to bypass the existing sand filter and that is not a problem.  I have a fairly large pump for the pool (20k gallons or so)..about  1 1/2 horse pump. I have no idea of the gallon/hr but I know it is big. It powers several jets into the pool with a VERY powerful flow.

What I was thinking of doing was cutting the existing lines and redirecting the flow into a large plastic barrel sitting on top of the diving board platform.

I thought of putting taps into the barrel at some point lower than the top  to feed the plant beds by gravity. i would have an overflow at the top of the barrel that would fall directly back into the pool. That way I would not have to worry about excess water flow.

I have planned planting beds on both sides of the pool along the deck. I think a simple ball valve will let me control water flow to each side of the pool for the beds. One side is far larger than the other.

Now for the questions...1. I have seen people talk about the necessity of a biological filter before the plant beds to allow for the nitrifying bacteria. Is that really needed, or do the planting beds themselves suffice?

2. As far as the plant growing beds go I am looking for the least expensive option.  For my present grow beds, I am using 4 inch sewer pipe with 1 inch holes spaced at 8 inch intervals staggered on 3 sides of the tube.  (Remember these are vertical). What are more economical options?

3. For the aquaponic system I was thinking about using similar pipe with connections that would direct the water flow into the first pipe and then in a zig-zag  pattern through the whole bed. then back to the pool. i think setting up mini bell siphons in each run (about 25 ft long) would be problematic....so...

4.Is an ebb and flow system that much more beneficial for plants than a continuous flow or NFT system?

5. i can always add fresh water to the pool and, by adding a tap to the barrel on the diving board, have a gravity fed source of water to run to my regular garden beds. i figure this will allow me to adjust for  for at least increased ammonia levels in the pool.

I welcome all comments and criticisms. I was trained years ago to think through a project to identify all the things that could go wrong and then correct them ahead of actually trying it.  However, this is all new to me.so I am doing this intuitively.

[Chris Carr]

Pat the depth will depend on how you cut the barrels I guess. I believe they are a bit under 24inches in diameter so they should run about a foot deep when split lengthwise. They are only a foot deep in the middle however. The unfortunate part about cutting barrels like this, which is a minor one is that you effectively lose 20% of the barrels total volume just in the dry top inch or two. You should get about 3 cubic feet for a half barrel though.

Correct me if I am wrong but the wet/dry aquaria setup you explained are what people here call constant flow. I believe the reason it works so well is that it allows good oxygenation for the nitrifying bacteria to do its thing vs a constant flood (typical hang of the back aquaria filter pad/sponge setup). const flood allows maximum surface area of the water to contact the bacteria and const flow allows for great aeration. Flood/drain allows for both and seems to be the most effective although all have their pros and cons. Flood/drain setups although great for filtering can have timers fail or bell siphons stop working and you can get into trouble if you dont catch it fast enough.

I recall someone extruding their own recycled plastics to make media but it didnt work all that well. I forget why and it was probably because it floated. Huge bunches of bird netting seem to be the favorite for massive surface area but doesn't hold plants. Best to go with for planting is gravel/hydroton/riverstone/lava rock/whatever is cheapest in the local economy that you are comfortable buying.

Speaking of media, biochar is a really promising media that Jon got me hooked on without even seeing it and Im pretty sure he was supposed to have a hands on class with it today. Jon? (Feel free to continue elsewhere as thats a total thread jack )

[Pat James]

"The unfortunate part about cutting barrels like this, which is a minor one is that you effectively lose 20% of the barrels total volume just in the dry top inch or two. You should get about 3 cubic feet for a half barrel though."

Chris, what do you mean by losing 20%? I know the outer edges of the media are going to be shallow, but once established, the root systems should grow towards the center and down. I wasn't as concerned with the cubic ft of  a 1/2 barrel as I was the surface or grow space.

I'm not sure what you are referring to with the constant flow system. What I was referring to is what I have seen called a 'bio-reactor' in a few videos, i saw. However some of them had the inert filter media at least partially submerged. i was talking about essentially spraying or dripping the water over the filter material. The material stayed wet but was NOT immersed in water.

I figured a filter like this could be added as needed if the bio-load of the fish tank exceeded the filtering capacity of the growbeds themselves. As fish can stand a higher level of nitrate than they can ammonia or nitrite, that would provide a stop-gap measure. If needed, partial water changes could be used to take off nitrates if the plant load is not sufficient.

[Chris Carr]

1.5inches off the top of each barrel half is 20% of its total volume because it is the widest section. Just something to note if you are calculating by assuming the volume is 55gallons. I agree doing them this way is great for surface/planting area and since you are not as concerned with volume of the beds then it is perfect.

I am saying const flow is what you are describing but applied as aquaponics terms using media beds. The beds are wetted from a spray bar of some sorts across the surface and the water trickles through the media, wetting everything and draining as fast as it comes in. There is never any flood/drain action in the bed. Its always wet but not submerged. Most people avoid this for the reason that a wet surface on media will almost always end up in unwanted algae growth after some time. In the aquarium world I believe these bio-reactors are usually blacked out or in a dark place like in the sump under the aquarium stand.

If its a supplement to your media beds and its not exposed to direct light then it sounds like a good option.

[Jon Parr]

Great thread.

Chris is dead on in pointing out that barrels split lengthwise reduce volume potential if keeping the top 2" dry in flood and drain. Barrels split around the circle have better volume properties, but only about half of the plantable surface area. In my experience, media volume is not as important as is sometimes touted. More important to me is the planted area. I have seen marvelous systems with no media at all, and no problems concerning biofiltration, or solids for that matter. The plant roots, all tank and growbed surfaces, and even the water column itself holds nitrifying bacteria. So, any flood and drain media at all is bonus.

Another reason I like barrels split lengthwise is that the rounded bottom acts somewhat like a cone bottom, aiding in evacuating all the water with each drain. I put a lenthwise perf pipe in the bottom of each bed now, acting like a French drain. Huge advantage there in performance and solids build-up, but water tends to get more turbid than if allowed to sludge up in a typical growbed.

Vlad, I think absolutely that Pat can stock according to his planted area, regardless of fish tank volume. There may be nutrient def caused by the simple fact of dilution, but maybe not. That question needs experience to answer, and I don't have it, yet. The one FT volume per hour is BS, and unfounded. It's a great place to start for hobbyists, but holds no merit at all in bigger applications, or DWC. The most successful commercial layout I've seen was about 1 FT volume per 24 hrs, and was coincidently the cleanest and most maintenance free system as well. See it here, and sorry for the vid quality. I filmed it to show my family what I was buying (which I didn't buy, and glad now I didn't). http://www.youtube.com/watch?v=NRkxMvbLAxg&feature=youtube_gdat...

[Vlad Jovanovic]

Jesus Jon, have a little mercy on us third worlders...jeesh, what is that like some super dooper 1080p high def resolution? Haha... Still waiting for the vid to load. My internet sucks, here in the sticks...Guess I'll type some nonsense while I wait...

Currently, I'm moving just a little over half my total fish tank volume every hour (1,200+ US Gallons)...and I don't plan on increasing that anytime soon. I honestly do not foresee that ever becoming a problem. (At least not with the bio-mass I plan on keeping...of coarse I could be wrong...but I doubt it)...

I am continually impressed by your knowledge and experience in the fish realm, so having you kinda confirm that FT/Volume/per hour BS thingy makes me feel more confident that it wont actually ever be a problem in my scenario...

Although I agree with what you say about all those surfaces performing bio-filter duty...IDK, personally I think there is a certain "peace of mind" with having a dedicated bio-filter and treating DWC, NFT blablabla...somewhat almost as 'add-ons' but that's just me...just a preference...

Seems like the more various helpful organisms and detrivores your system has, the better...Especially a system without any sort of 'dedicated' bio-filter...I bet those scuds (Gammarus) go a looong way in helping with not just keeping solids down, but unlocking the nutrient potential contained within those solids...

It's a shame that place shut down...looked like it had some pretty damned impressive potential. (The video finally loaded :)

 

[Pat James]

I have not mentioned this before on this site but I am not altogether unfamiliar with maintaining a heavy biological load under a 'pump' system.

I run a heart/lung machine during heart surgery, so essentially,it is my responsibility  to maintain a balance. There is far more than just providing oxygen. The principles are similar IN SOME WAYS, to what we have here in AP. You can increase air flow/ventilation or oxygen % or fluid (in my case blood) flow rate, to balance this. I also can decrease biological load... For a patient, I can regulate body temp. Plus I can add anesthesthetic gases. This is akin to the fish load.

I even buffer the solution if necessary.. and I use simple sodium bicarb to do it. Each thing I do has a reaction and a byproduct that I have to take into consideration.

Biological systems are not that different. You just need to apply the principles to the matter at hand.....

[Jon Parr]

Amen to that, Pat. I thing the heart/lung machine trumps the biofilter science we are playing with
:)

Vlad, thanks for the compliment, and likewise. Btw, did you get your bulb? I like to have some flood and drain media somewhere in every system as well. It's kind of like a heart/lung machine for Aquaponics, to play with the recent analogy. In fact, when I know I'm going to start up a new system, I add a bucket I gravel to an existing system for a couple of weeks, then use it as life support for a new system until the new one can "breathe" on it's own.

[Vlad Jovanovic]

Yeah Pat, I think that AP is just a tad simpler than operating a cardiopulmonary bypass pump

I tend to look at bio-filtration as the main 'gig' in AP...You don't really need the fish, you can use other organic nutrient input sources, but only if your bio-filter is well....on the other side, you don' really need the plants (if you have fish, say) because there are other ways to get rid of excess nitrates, but again only if your bio-filter is well...to process whatever NH4 input, to NO3 in the first place.

So, if we break it down into it's 3 most basic components, you can go without 1 of the 2 components (fish or plants), but you can never really take out that 3rd bio-filtration component without it resulting in a system collapse.

To me the health and well being of the bacteria is paramount, on a number of levels. When people ask me what I'm growing in the AP greenhouse I tell them 'healthy bacteria...oh, and some plants,... and maybe eventually some fish along the way'...

Jon, still no bulb  I was afraid of something like that happening. Maybe it'll show up here one day..? (hopefully sill in one piece)...

[Pat James]

Today, I turned on the pool pump bypassing the sand filter. No filtration is going on but the pool is now being actively oxygenated all the way to its 11 ft depth.My full school of rosy reds (fathead minnows) seemed to be doing well even in the stagnant pool. I figure that mechanically oxygenating their environment cannot do anything but help.

I am thinking of re-visiting my idea of using the existing pool pump as my primary source to move water. If I can locate one or 2 other pumps I will use them for a separate filter system(s).

I have not been able to locate either food-grade barrels or a filter media at a reasonable price.... I've heard about a couple expanded clay products and wondered if anybody here uses them... Arcillite or Turface.

In the meantime, as soon as my slotted pots arrive, I am going to start some 4X8 raft systems directly on the pool surface. I'm hoping my present oxygenated water will work. If nothing else, those rafts will provide some shade in the pool later on..

[Jim Troyer]

Hey Pat

How is this grand system working out by now?

Maybe some pictures too?

all the best,

Jim

[Adam Vicknair]

From what I understand, If your grow beds are media based then you should not need a bio-solids filter in your system, only NFT and Raft systems need those. I don't know if it is possible to do NFT vertically but continuous flow is possible in a vertical system. Ebb and flow is the simplest type of system from my experience though. Post pics and people will comment more and have more accurate advice. :D

[Pat James]

Jim, If you go to my profile you see my blog on my swimming pool system. I am using 1/2 IBC's for grow beds...mainly rafts because of the expense prof media for that many beds.

I stocked the pool with 300 channel cat fingerlings and a pound of fathead minnows (which are breeding). I am not sure how many of the channel cats survive...I have seen maybe a dozen or so bodies or parts of bodies. I also have crawfish as scavengers.