Backyard Aquaponics
A place to discuss aquaponics

The back flush is done with both air and water. First you bubble air through the media and this helps release the solids. You let these begin to settle and then you flush out the water along with the solids.

Looks like with the inner bucket in your drawing that your going to do more of the combo filter rather than the straight MBBF/MBBR filter.

This is a drawing of the water pipes (i didn't get the inner bucket back flush exactly as you have it though ) - having the water pipe at the outflow collect from the bottom (as you drew it) is probably OK but since your flush drain pipe is going to be separate, I'd keep it off the bottom just a bit so it doesn't pull any solids (probably won't be a lot anyway but you don't want much of them going back to the fish tank).



I wouldn't put any air into the pipes within the filter. The air should go on the bottom of the big tank, the air is there to agitate the media within the big tank (keeping it self cleaning) and to provide oxygen for the bacteria to process waste. This air will run most of the time. I did a 1/2 inch PVC pipe with a union so that I could remove the pipe from the filter if needed. The air is coming from a circular loop of flexible hose - this isn't perfect in that the loop isn't exactly even so air distribution on one side is a bit better than the other.

You'll also need air to the bottom of the inner bucket but you'll only operate this when you're cleaning this portion of the filter. The idea is that the incoming water percolates through the floating media and this traps the solids or causes them to fall out of suspension for various reasons. Those that are held in the static media are released when you bubble air through. It's helpful to raise the water level before you bubble the media and you have to somehow cover the slots in the bucket when you do this or some of the solids will flow out the slots instead of out the back flush drain. Air is brought in with the PVC pipe and loop just like in the bigger bucket.

Usually when the air is on in the outer bucket, it's off in the inner bucket and vice versa.

I can see by the inner bucket back flush piping that you're working against some space constraints. I can tell you it's going to be a real pain trying to plumb the pipes together under the inner bucket and line everything up. So much easier to change an elbow outside the barrel to a T piece if that's possible. If you have a shop that sells awnings they sometimes carry oddball PVC fittings that will do this for you. 3 way elbows are what I'm thinking of but they may call them something else. These are also used in PVC greenhouse kits and furniture so they can be found at least up to 1.5 inch. They are often beveled on the outside so they look a bit different than normal fittings.

http://www.lowes.com/pd_315499-1815-413010RMC_1z10xvn__?productId=3344668&pl=1

Thanks CoachChris,
I sealed the upper window frame, removed the LED light, the failure was the connectors on the extension cable, I forgot to snug them Oh well.
I haven't had time to decide if I want to move the upper LED down, or just leave this a one LED spotlight system. It was so cool looking with two, but I need to refill the pond.
We are busy harvesting honey


We're out of practice working with bees. I got stung four times just harvesting one super out of four.
I'm here to tell you, it is quite difficult staying calm while being stung, but I did. The breeze kicked up a bit, and they weren't terribly happy about my finesse or lack there of. Hardest is separating the hundreds of bees from the honey frames without irritating them much. It just means moving the horse hair brush over them slowly slowly slowly without making them fly

"I can see by the inner bucket back flush piping that you're working against some space constraints. I can tell you it's going to be a real pain trying to plumb the pipes together under the inner bucket and line everything up." now I can't recall if this is the latest drawing you supplied. Also I mistook "A" for air instead it means atrium gate. The two pipes are not tied together it your sketch. It's good to draw it out first.
" I wouldn't put any air into the pipes within the filter. The air should go on the bottom of the big tank, the air is there to agitate the media within the big tank (keeping it self cleaning) and to provide oxygen for the bacteria to process waste. This air will run most of the time. I did a 1/2 inch PVC pipe with a union so that I could remove the pipe from the filter if needed. The air is coming from a circular loop of flexible hose - this isn't perfect in that the loop isn't exactly even so air distribution on one side is a bit better than the other."
I'll start reworking the drawing, and my plan.
Thank you Scotty, you are a life saver

That last drawing was a rework based on what you seemed to be doing in your drawing and it's for a combo static and MBBR filter. If you find it too difficult to deal with the inner bucket it would be super easy for you to do a regular MBBR filter with your already existing pipe setup - I posted this earlier, probably in the thread where you were asking about filtration - it should be the only drawing without an inner bucket unless I messed up. That was what I was pointing you toward before because it was easier with your location to do. It also has less maintenance because you aren't trapping the solids like you do with the inner bucket in this design (this means some solids pass through and you might have to waste some water from the system to keep the suspended solids down). I suspect that you're going to have to waste some water to keep the water quality up anyway (since you need more filtration) so at this point it's not a big deal.

I hope this makes sense, I know you've got a lot going on.

P.S. The aspen is probably a good way to get your bacteria going but it's not going to get the flow rate up - that's the nice thing about an RFF - no obstructions. I'd take your drawing and start adding flow rates for the filters, they can only handle so much. An RFF with too much flow will just flush everything through

I see, I'll keep researching this idea of straight MBBR, although I think I got the static bucket figured

Hi Brian,

I have been watching your trials and tribulations every other day, very entertaining and engaging.
Congratulations to you, you really have worked up a marvelous system despite a great deal of hurdles.

I do not profess to have the knowledge and skills of many here and my setup is rather ad-lib with adds and changes every other week.

I do like to keep filtration simple though

I use a Static K1 Barrel (about quarter full with K1) with the water from the pond coming in through the base of a barrel, just one aerator ball to provide a degree of solids agitation (not too much just enough to kick off the rising solids). I can open the base drain and fully empty this when cleaning. This solids filter then flows to a moving K1 barrel and then back to the pond waterfall.

There is some other stuff going on with trickle feeding from the static K1 to the vertical garden but that's another story

In addition I have a skimmer on the surface of the pond to catch leaves and floating debris. Which also helps to swirl and circulate the surface.

My filters are pretty simple however are really easy to clean. I never need to clean the moving K1 Barrel, and I just agitate the static K1 barrel and fully drain it once a week (if I am good)... ok once every other week.

My water clarity is pretty good.
Here is a clip of my system (sorry it's getting a bit dark out). https://goo.gl/photos/ujS4QC4MaWvKqwdo9

Cheers and keep up the great work.
Stuart

Thanks dogdoor, that is good to know. For some reason I couldn't get the video to play, but what I saw was very pretty.

I wasn't certain if I did have the room for a T after the valve, but yes, it looks as though I do. I was looking in my MBBR now that the FT is half empty, oh yeah; we drained it as we could not get ahead of the silt from the red scoria.

What I saw when I looked in the MBBF was those little K2 bits really can get in everywhere. I just pulled two out of the holes in the end cap. I couldn't for the life of me get one to go through!

I'm beat, I forgot how arduous working with bees is, and I only got one quarter of the way through the supers I need to do. Thanks to Nell for all her help and effort. I've decided to quit smoking the vapor pipe in support of what she is doing. This day seven for me and twenty five for her. I have a thousand reasons I keep busy, now I have another one, sheesh. We love watching streaming video at night to relax, now pretty much all I can think about while watching is the fact that something very important is missing from what I am normally doing.

Oh boy as I sit here at my desk in the living room, just outside the greenhouse, I can hear water moving through the filter again. That means the water level is up to the SLO (solids lift outflow for my non-aquaponics friends) The SLO pipe exits the pond four inches below the water level, which is set by the large overflow pipe into the sump tank. Speaking of such;
In your drawing Scotty do you think something will change in my system when I re-plumb for this?

Because right now without a riser between the MBBF (moving bed bio-filter) the water level in the MBBF is perfect. BTW, the outflow from the MBBF is only slightly down tilting and drains in the sump tank above the water line there. In other words that outflow from the MBBF is open to the air.
I'm starting to think from what I'm reading here that I need need to add a second MBBF 200 liter barrel. If this is the case perhaps I should just plan on one static MBBF (is this a oxymoron?) and one fully aerated. Let me go look now that the sun is up and see if for certain I can fit second barrel. No not really Perhaps I can find a rectangular HDPE tank to fit the remaining space back there. For now I'll move ahead with the combination static and moving bed filter

Brian, I know your too busy now, and my hives not coming for a few months, but when you get some time, I'd really love to pick your brain on the bees. Bee newbie and clueless. I've been doing some research in preparation, and will be doing more as the time nears. I did find a local who has bees for sale.

Brian, I was concerned about the flow out of the MBBR. If you already have it plumbed as you drew it and it's working then it's probably OK to leave it that way BUT if there is anywhere that air can accumulate and become trapped or a siphon form you'd want to avoid that (which is why I added the open ended riser). I'm not certain you need the open ended riser though, it's a precaution. You already have a riser if you've done your pipes as in your drawing and this is setting you water level so that's taken care of. The decision on whether to change to an open riser on the outfall

Is there enough space to put the IBC you got in that area if you removed one of the barrels? Right not without doing that you could have around 3 cu ft of media in the MBBF so enough for about 60 pounds of fish based on the manufacturers specs. You could put a lot more media in the IBC if it would fit. As I recall your sump is good sized and you might also be able to convert part of the sump into an MBBF by netting off an area, adding K2 and aerating heavily. It would be just like adding another filter in line. By this time most of the solids would be taken out anyway (if not, cleaning might be an issue).

I redid the vid and put it on youtube for you. Just some ideas for you to contemplate
Cheers.

Scotty wrote: That is a fascinating idea. I was kind of thinking along the same lines with one of the dirt tanks over in the corner near the filter area. We've got one grape in there now. It is almost as deep as the filter area and not as deep as the sump tank. I like the idea of employing more MBBR for higher fish stocking density as I have less space in the greenhouse and I need to keep the clear roof covered most of the time to keep the heat and direct sun minimized. I'd guess that tank size over in the corner is 300 gallons and it does have an opening very near the bottom for a clean out ...

Conversely, I intend to build the largest media grow beds next. I was going to go with DWC, but that seems less advantageous to my system now. I can add (lemme do some quick numbers here) One bed can be as large as 2.5' X10' x 1' = 25cf or .7cm -- another 4'x5'x1' = 20cf or .5m³ for an additional 1.2m³ of media grow bed. I read in the FAQ just now that 2m³ of media grow beds can support 60 lbs of fish in a 2:1 ratio system(gb:ft) system, which of course I do not have. I'm just trying to wrap my head around these basic numbers... I've got a 10kl or 10m³ FT with a 2:1 ratio I'd need 5m³ of media beds. I've also got four .37 m³ media beds equal to 1.5m³, plus 200l or .2m³ MBBR. I guess what I need to know is a comparison of MBBR to media grow beds on fish stocking, minus the other factors like water temps, pH, feed rates etc.

Newb question; What goal should I have for a big fat multi-season brook trout? They've got two year old Gila trout in a nearby hatchery which are 16 to 18 inches long. Although they are breeding pairs and surely the largest healthiest trout of the batch. I know I'm being all pie in the sky, but until all the trials tribulations and multitude of issues coming my way I cherish these moments

Regarding the DWC to media bed switch - not sure it's a good idea because of the potential for higher temps with greater heat exchange area - might work, might not. With DWC you have the foam rafts acting as an insulator.

You'll also get filtration from a DWC bed once the plant roots have grown but you do need to prefilter the water going into DWC so that solids don't coat the roots. FYI I'm not sure what the filtration capacity for DWC beds is but I've seen it on some of the UVI information, just don't remember where.

Your grow beds are bigger than I thought. Based on 1 lb of fish per 5 gallons of grow bed media you could have a maximum of roughly 80 lbs of fish http://www.backyardaquaponics.com/forum/viewtopic.php?f=12&t=6646.

1.5 cm X 35.31 cf/cm = 52.965 cf which is around 396 gallons (7.48 gal/cf) --- calculates out to around 79 lbs of fish for your media beds - Maximum. You really don't want to push it this hard initially.

If you purchased the same media that I did then you can get the information on how many pounds of fish it can support off the page you ordered it from http://www.ebay.com/itm/Kaldnes-K1-K2-K3-Bio-Filter-Media-56-63-Liter-or-2-Cubic-Feet-/221298358461. But it's only an estimate - roughly 42 pounds of fish being fed 1.5% of their body weight per day OR 0.55 lbs of food can be processed by 2 cf of K2 in a day. You can back calculate the maximum amount of feed that the 52.965 cf of media beds will handle per day as being around 1.18 lbs for fish being fed 1.5% of their body weight (79 pounds of fish X 0.015).

Total calculated maximum right now of 1.18 (for media beds) + .55 (for K2) = 1.73 pounds of food that can be processed by the bio-filter. Don't try to go this high, lots of things can affect the processing ability of the bio-filter. All this is for is to give you a ballpark estimate.

Keep in mind that young fish eat a higher percentage of their body weight each day. I usually just feed what the fish will eat in a given time but the table here will help you calculate roughly how much your fish will eat at a certain size and how much filtration is needed - http://www.extension.org/mediawiki/files/c/c1/Trout_Production_Feeds_and_Feeding_Methods.pdf

Keep in mind these are just estimates. If you look around, the way things are calculated varies a fair amount. Dr Nate Storey has a good video explaining some of the calculations using specific surface areas and biological surface areas - https://www.brightagrotech.com/biological-surface-area-in-aquaponics/. We haven't even touched on this, it's an interesting video and with some additional work we could probably get another estimate this way but I think we have what we need.

Hopefully I've done the calculations without anything that throws the estimates too far out of whack.

Cheers

Brian,

I am just a system-less newbie to the game, but eagerly soaking up all info I can get!
IF I am not totally mistaken - the 1:2 rule is the other way around:

1 FT : 2 GBs. Obviously that makes your situation worse, so you just will have to calculate with fish weight vs. Media-GB volume - getting 20m3 of GB media volume IS a tough task!!


All the best!

Your system is an epic challenge to watch! Never mind your climate!!


Cheers,
thjakits

Good catch thjakits. Thanks Scotty, I mean you really went through the numbers, explaining everything clearly. For your effort I owe you. Let me know if there is anything I can do to return the favor.
My gout is still stinging in my ankle. Still I had a fantastically fun and productive day installing a new air delivery system from parts I had on hand. In an unusual spate of flare, my "Touch of OCD" techniques made me satisfied, I did what I could do, well, imho.


These two projects are combined and the bulk is sitting on one 6 inch thick 12 inch wide plank set into the ground on two wide cement blocks all under a deep overhang.

First thing needed was connect the batteries. While mostly I've routed the heavy battery cables run around the cell caps, but a couple were blocking the caps removal. I decided I better check the battery water before tightening the cables. They were dry, sheesh, I used to be better at periodic maintenance. Oh well, gotta do it. Cleaned all the terminals torqued the battery wingnuts exactly the same. It is important to keep the paths that electricity travels equal. Electricity follows the path of least resistance. So if one cable is fatter and tighter or shorter, that's the way the electrons will run. Keep this in mind for the load as well as the charge side.
After I got the inverter on-line and the pumps running from battery power, I decided to install the five PV panels on the roof. I made some brackets, sealed and screwed the panel to the highest point on the roof. Again nobody will see it out here in the middle of nowhere, but it made me happy to do a clean wiring job.

OMG, it is so quiet in the greenhouse now. Just the sound of trickling water, interrupted occasionally by the sound of a siphon breaking or air escaping from the SLO air lift pump.

Now for more fun fun fun
I wasn't certain what CoachChris was talking about when he said some of his diffusers were loud. With the air @ full flow this little thing roared at six foot depth!



Air diffuser is made from PEX, all submersed copper and brass are coated in silicone sealant.
I've drilled several smaller holes near the "T" and four larger holes near the inner portion of the diffuser ring. The idea is the close to the supple holes don't need as much flow as the farther holes. It seems to work. Keeping the ring level is important for the best distribution of bubbles. I probably should have installed the diffuser ring before the K2 media, but what the hell. it is far better than it was. All the K2 on the surface is rolling.I still need to measure the retention time in the MBBR, again I'm stoked.

I'm one happy DIYer
Brian