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chrisfoerst
04-20-2011, 01:06 PM
I have another issue. The fish poo and sediment is collecting at the bottom of my 75 gallon tank and doesn't appear to be taken up at all by the pump. I am using a Quiet1one 1200 which works great otherwise. The only other thing I have in the tank are air bubbles from a whisper 300. Does anyone have a recommendation for getting the fish waste into the pump? Or, am I missing a step all together?

keith_r
04-20-2011, 01:18 PM
what kind of tank? i have to occasionally vacuum out the bottom of my rectangular fish tanks.. but the slo's do a pretty good job of getting most solids into my "middle" tank - i've got 3 55gal glass tanks with the beds overflowing into the outside tanks, and the pump running in the middle tank

chrisfoerst
04-20-2011, 01:49 PM
It a regular 75 gallon glass aquarium. By vacuum, do you mean one of those hand operated siphons? what kind of tank? What does slo stand for?

I have my tank on boards and around it rests a wooden stand I built that supports two half barrels. The water is pumped up to the barrels and then returns to the tank. I am testing Oliver's theory that a bio filter can double as a grow bed if they are at least 12 inches deep.

Thanks for the help!

davidstcldfl
04-20-2011, 01:59 PM
Hi Chris, SLO AKA.... Solids Lifting Overflow. You can see a :oops: drawing I made of one here....
Flow or the water (http://www.diyaquaponics.com/forum/showthread.php?507-Flow-or-the-water)

I don't pump my solids...so I can't help you there...

The grow beds 'are' bio-filters, ( and most of the rest of the surfaces in your system, to one degree or another)...once nature has some time.

rfeiller
04-20-2011, 02:45 PM
You can also create a current that directs the waste to the pump. But you will still need to do house cleaning.
Using the grow beds as Bio filters works good for me, even at 6 inches or less. You can have any surface at any depth it can be used as a biofilter. There is a filter surface area where the badcteria can colonize to bioload volumn calculation. There are endless arguments about what media and methods are most efficient, don't worry just keep the water circulating for oxygen. At a 12 inch depth you have way more surface area then necessary.

keith_r
04-21-2011, 05:20 AM
my tanks are standard glass fish tanks (trying to figure out a bigger diy tank now).. as noted, slo is "solids lift overflow" so the water is drawn from the bottom of the tank into the tank with the pump
my "vacuum" is just a plastic tube i fill with water and siphon from the bottom of the tank.. an aquarium vacuum/siphon would be fine
in the summer this water goes to my dirt plants
and yes, the growbeds are biofilters, i have worms in mine to break down solids, and keep the roots clean. if you have sufficient growbeds, you won't need any additional mechanical or biological filters (unless you want to "polish" your water

urbanfarmer
04-21-2011, 10:06 AM
I always get you fellers confused because of the prominent "r" in both your names...

Anyway, you have one other option since it's a small fish tank. You can add gravel to the bottom and then add some composting worms to the gravel. The worms will eat the fish poop, and the worm poop will be eaten by heterotrophic bacteria and released into the water in a process called mineralization. The plants can then absorb the processed waste matter.

rfeiller
04-21-2011, 02:29 PM
The raft system is the only system that has had a negative affect with the detritus the other systems seemed to have benefited from it. I need to add an interim vessel for the detritus to break down.

urbanfarmer
04-21-2011, 02:44 PM
The raft system is the only system that has had a negative affect with the detritus the other systems seemed to have benefited from it. I need to add an interim vessel for the detritus to break down.
Unfortunately, you are right about that. There are several ways to filter it out efficiently. If you need some ideas designing let me know. I have thought about it more than once! :lol:

rfeiller
04-21-2011, 10:31 PM
i am going to set up two 4x4 trays to try out the air gap theory versus the air stones. the 6" in depth raft will have air, the 12" will have an air gap of 2". ahead of the two trays i'll install a sediment filter to attemp to seperate out the detritus. we'll try to kill two birds with one stone.

urbanfarmer
04-21-2011, 11:27 PM
Please keep us updated!

chrisfoerst
04-22-2011, 07:45 AM
David, Ok, now I get the SLO method, it’s always helpful to have a visual. I will keep it in mind for another system down the road.

rfeiller, What is the best way to create a current? That sounds like my best option at this point.

Urban Farmer, I am intrigued about adding worms to the gravel at the bottom of the fish tank, but wouldn’t they drown being submersed in water like that?

Thanks for all of the responses!

keith_r
04-22-2011, 08:25 AM
worms breath through their skin, as long as the water is oxygenated, they'll be fine..i have worms in my gravel growbeds doin the job, i wouldn't use gravel in the ft, unless i was using an undergravel filter

chrisfoerst
04-22-2011, 08:36 AM
Ok, thanks so much! That's what I'll do.

jackalope
04-22-2011, 09:01 AM
I had that problem, once, fish poo standing in the bottom of the FT ..... then I took an external filter (Cascade 400) and put the suction in one end of the FT, and the return in the other end of the FT .... Viola! .... it created a 'current' that would cause the fish poo to be driven/sucked into the suction end of the filter. I had plans to revise this approach, by using a piece of PVC pipe on each end , drilled with lots of holes to be able to spread the 'current' over the whole width of the bottom of the tank .... but Winter in Montana came along. One tank froze, even with the heater, and broke out the bottom, drained out when a thaw came along, etc., etc.

I think if you are sucking the water from one end of the FT, running the water into a sump, it will force the fish poo into the sump, then cycle the water into the GBs, then drain the water from the GBs back into the opposite end of the FT it will do the same thing that I experimented with using the external filter.

Just my 2 centavos ...... YMMV!

urbanfarmer
04-22-2011, 01:48 PM
Hm, well the setup I had was a fish tank with gravel and worms in the bottom. I had 1 pump taking water up into a hydroton grow bed that would flood and drain. The more "floaty" solids got stuck in the grow bed, and the heavier turds would sink down into the gravel. I only put in 3 or 4 worms to start and in a few months there were tons of them and REALLY FAT. My plants were growing off a few CFL bulbs, and to be honest they were doing better indoors than outdoors by about a factor of 300% in size and vegetable yield (I had peppers mostly). Anyway, it was fun to eat dinner in front of my TV and reach over to my pepper plant and pick a few to add some more spice to it. :mrgreen:

I don't grow indoors anymore because it freaks out the ladies when I bring them over... Worms are especially scary and whatnot... :lol: :lol: :lol: :lol:

chrisfoerst
04-23-2011, 09:28 PM
Hi Jackalope,

I'm going to include a sump with the second system that I am going to start building this coming week and compare how it does to the other one. Are you the one who I spoke to about swirl filters?

chrisfoerst
04-23-2011, 09:37 PM
Hi Urban Farmer,

Well, I happen to be a lady who digs worms! This is great, your system sounds very similar to mine. Did you need an under gravel filter of any kind or was it just the gravel and the worms? Did you add any extra air flow under the gravel?

urbanfarmer
04-24-2011, 12:16 AM
Hi Urban Farmer,

Well, I happen to be a lady who digs worms! This is great, your system sounds very similar to mine. Did you need an under gravel filter of any kind or was it just the gravel and the worms? Did you add any extra air flow under the gravel?
Well, you are one of the few! :lol: I just had gravel and worms. The fish were all fairly small. If I recall correctly, I had 30-40 small goldfish in a 10 gallon tank. They definitely produced TONS of ammonia, but the system converted it EXTREMELY rapidly. I was so impressed. The floaty type solids were sucked up by the pump and typically got left in the growbed above the tank. I did have the water aerated with a bubbler at the time as I did not know any better. I think I had the bubbler in the gravel, but that was just to keep it weighed down as it tended to float otherwise. This was not needed though and didn't do anything extra for the worms being in the gravel.

chrisfoerst
04-24-2011, 07:59 PM
I have air bubblers in my tank right now because it was the best, immediate way I knew of to add oxygen to the water. Are you saying that there is a better way to do this?

urbanfarmer
04-24-2011, 09:00 PM
It's a difficult issue to discuss because of the contradicting view despite basic scientific principles. To be honest, the issue has not even been settled here on this forum between the members, and I have not been inclined to put together the information required to settle the matter. I don't use air bubbles in my system and there are no signs from the organisms I am cultivating that I need to. With that said, an air bubbler is just fine for your setup. You can't HURT anything (besides your wallet) by buying equipment for the system to add oxygen.

Short answer: Yes, there's a better way. No, you don't need to know about it right now. :mrgreen:

rfeiller
04-24-2011, 09:11 PM
you can create a current with the air stones, a power head a submersible pump.
an air stone will live the water and draw water to it, a submersible pump will do the same thing.
if you place an uptake at one end and push the water from the other end you will create a current that will carry the sediment to the uptake. as jackalope was discribing

i maintain air stones in all of my tanks to circulate the water. it prevents zoning of the water, temperature and oxygen dispersement.

urbanfarmer
04-24-2011, 09:47 PM
Do you have data to indicate the rate of diffusion of oxygen in water or aqueous solutions is slow enough to create "zones" in your water column that are low enough to kill your crop or reduce your yields? It seems counter-intuitive to me. I ask you, please heavily question your assumptions.

4 ppm (4 mg L^-1) of dissolved oxygen is recommended by Dr. Wilson Lennard; however, scientific research clearly shows that fish like Tilapia are capable of surviving and growing in waters with less than 1 ppm DO levels. Depending on the temperature, most backyard systems will not drop below 2 ppm DO, and usually not below 4 ppm DO. Unless you are running a high density fish stocking regime in a commercial environment, why the heck would you even bother making your system more complicated, more costly to build, and more costly to maintain? Aquaponics as a solution for world hunger would dictate that poor folks in 3rd world countries would neither have access to or the means to add this kind of equipment, yet many organizations are designing systems that work for them. Rightly so! I understand wanting to have the BIGGEST, SHINIEST, and MOST EXPENSIVE system, but it's just not needed. Please be sure to indicate to people that you add all the fancy bells and whistles because YOU WANT to NOT BECAUSE THEY HAVE TO.

With that said, there are SO many factors that can contribute to the overall performance of your system. Understanding the science and technologies involved will allow a person to troubleshoot or diagnose specific problems to their very unique system and production goals. I can easily give you a context where the information below would really not help, but I think it puts my point on dissolved oxygen into perspective.

Several tilapias are reported to tolerate oxygen levels of 0.1 – 0.5 mg/l (O. mossambicus, 0.1 mg/l, Maruyama, 1958; O. niloticus, Magid and Babiker, 1975; O. mossambicus 0.4 mg/l at 30C and 0.6 mg/l at 35C in closed respirometers - Mohammed and Kutty, 1982; Tilapia guineensis and Sarotherodon melanotheron and O. niloticus - nil oxygen, water depleted of oxygen by a addition of tobacco waste in low concentrations, but fish allowed access to air - Kutty, unpublished).


REFERENCES
Magid, A. and M. M. Babiker. 1975. Oxygen consumption and respiratory behaviour of three Nile fishes. Hydrobiologia. 46 : 359 – 367.

Maruyama T., 1958. An observation on Tilapia mossambica in ponds referring to the diurnal movement with temperature change. Bulletin of the Freshwater Fisheries Research Laboratory, Tokyo . 26(1): 11-19.

Mohamed, M. P. and M. N. Kutty. 1987. Observations on low ambient oxygen tolerance in some freshwater teleosts. Experimentia, 129 – 138.

keith_r
04-25-2011, 05:38 AM
so if you look long enough you can find fish that can live in low do.. but why would you want to set up something that isn't going to have best performance? just because a fish will "survive" at minimal levels, doesn't mean you'll get the best growth of the fish! (or the plants for that matter)

urbanfarmer
04-25-2011, 02:15 PM
I didn't see if the study discussed the fish growth. I think in general everyone disregards the fact that there is another factor at play... the air around us. The reason those fish survived is because of the air. Plants in rafts or gravel grow beds that drain have roots and bacteria exposed directly to air. It reallly, REALLY, depends on how you have your system set up and if you took into consideration different factors when you built it. Most backyard aquaponicists do not need to add aerators to their systems.

Just like we graduated to the concept of using 1 pump instead of 10 in our systems, we need to learn to not use any aerators.

cedarswamp
04-25-2011, 03:16 PM
How are the folks in the 3rd world pumping water?

IMHO aeration gives you a little wiggle room to compensate for our human error/neglect. I've never run a fish tank without also running aeration. To paraphrase/quote? Dr. Wilson Lennard, "Take care of the fish and the plants will take care of themselves."

While fish may adapt to lower levels of DO, the stress it may cause IMHO invites disease/pathogens.

davidstcldfl
04-25-2011, 05:59 PM
It really, REALLY, depends on how you have your system set up and if you took into consideration different factors when you built it.
Nothing like a good diy spray bar or a venturri... :D

Most backyard aquaponicists do not need to add aerators to their systems.
That's true in 'some' cases. If I were to make such a broad statement, I'd be more inclined to say something like.....'Most' backyard Aper's are stocking too many fish and 'need' to run an aerator.



I agree with Ceadarswamp. "Wiggle room'' is key to a succesful operation.
Redundancy is our friend. 2 smaller pumps working together, on separate circuits....toss in an air pump and you have the old "Three folded cord'' thing going on. Even in a backyard set up, that's not really out of the question. Compared to the possible loss of fish and the frustration factor.

urbanfarmer
04-25-2011, 10:54 PM
Nothing like a good diy spray bar or a venturri... :D

I couldn't agree more!!! ;)



Most backyard aquaponicists do not need to add aerators to their systems.
That's true in 'some' cases. If I were to make such a broad statement, I'd be more inclined to say something like.....'Most' backyard Aper's are stocking too many fish and 'need' to run an aerator.
Well, I said most because I don't think the majority have a high stocking density... but yes I don't have true statistics to back that statement. I guess I should have said:

Most backyard aquaponicists have the space and resources to create enough water volume and tank surface area to prevent the need for added aerators and should use in lieu of such equipment the return water flow as a source of surface agitation for gas exchange and aeration. :mrgreen: Happy now, sir??

badflash
04-28-2011, 04:08 PM
As long as the pump keeps running, you don't need bubbles. If the pump stops the bubbles buy you lots of time to fix it. Making bubbles costs very little in power or material and can run on battery backup.

urbanfarmer
04-28-2011, 04:25 PM
As long as the pump keeps running, you don't need bubbles. If the pump stops the bubbles buy you lots of time to fix it. Making bubbles costs very little in power or material and can run on battery backup.
With a high enough stocking density, this is most certainly true. Often, I find myself taking an exaggerated stance on something to prove a point. The Truth lies somewhere in between... :mrgreen:

mespe
06-27-2011, 05:32 PM
In my system, I pump from the sump tank (under the GBs) into the FT. The pumped water runs up a 1/2 CPVC pipe (because it fit the pickup hose of the pump) it then goes to 1/2 reg PVC with a 90 elbow going to 1 one inch pipe. The 90 elbow has a small hole drilled in it. The theory is the water going down the bigger pipe sucks air into the small hole. This air is forced down the 1 inch pipe and I would imagine that the air is violently opposed to being forced down 6 inches of pipe. I know that air goes down the pipe because I see tiny bubbles emmitted from the bottom of the pipe.

kneedeepinwater
09-20-2011, 07:17 PM
I'm not sure if you were able to straighten your problem out. Did you add the SLO that seems to be the thing to do from the jump and is very efficient. I would do one more thing that would benefit your fish and plants and also keep the fish poo stirred more and that would be trying to get more water movement in my fish tank. Your water will be stirred up more which will also give your fish more current which they will benefit from and also possibly add more oxygen to everything bc of the extra water movement on top of the water.