Benneficial bacteria

[Pierre Riche]

       Benneficial bacteria is somewhat of a mystery to me. The only thing i realy know about it is that when a system has a good colonization of it then plants get fed and fish get cleaner water. I know that with an established bacteria amonia gets turned into nitrite and nitrite into nitrate and all is good.

     The project:  I'm building a 50 gallon AP system. 25 G. in the tank and 25 G. in the bed. The bed will be floating raft, the fish undecided, probobly koi maybe catfish. 

   The issue: this will be a display model so it will travel. I will have to transfer the water and fish from tank and bed to 5 G water jugs or other containers.

 

    Question:  How long will the bacteria last in the jugs?

                    Does it need oxygen and movement? 

                What can i do to keep it healthy durring transport and to reactivate it when its back in the system?

[TCLynx]

You will need some form of bio-filter since the bacteria doesn't colonize the water so much as it colonizes the surfaces in the system.  The bio-filter bacteria likes dark, wet, well aerated places with access to the ammonia/nitrite it eats.  So in addition to the fish tank and raft bed, I suggest you add a bucket with some sort of material to act as your filter.  This can be as simple as a 5 gallon bucket that the water flows through filled with scrubbies, bird netting, shade netting, lava rock, bio-balls whatever material you want to stuff in it and add aeration to that bucket as well.  This will not only give you a filter for your little system but it will give you a handy way to transport the "bio-filter" portion of the system.

 

I'm going to recommend against catfish (at least channel Catfish) for such a system since except for when they are really small, they don't do well with extra handling and transport.  Also a 25 gallon tank is way to small for a channel catfish for very long.  Actually, a 25 gallon tank is too small to grow any fish out to eating size so I would recommend using fish that are small long term unless you will have a steady supply of replacement fingerlings.  Green Acre Organics started out taking a display system to market on the weekends but had trouble with the fish not surviving the constant handling and transport well, this is likely to be the biggest problem.

 

When you talk about transport and reactivating things when back in the system, how long are you expecting this transport to take?  I would recommend keeping the fish water (with fish in it) and the bio-filter aerated in transport.  The plants will also need aeration in transport (you might ask Green Acres Organics how they managed this for their live plant sales at market.) Green Acre Organics

I don't think you will do all that well if you are planning on packing things up for transport for more than half a day at a time.  As in you can't really pack the fish and plants up into 5 gallon buckets and coolers and leave them without filtration or flow for the weekend.  If it is only a few hours or so from when you packed things up to when you set it back up, I would just re-fill everything, make sure the temperatures are equalized for the fish and hook up the pumps and away you go.  However, if you let things die off, and you have to cycle things up from scratch, well you might want to read up about fishless cycling.  Fishless cycling

[Pierre Riche]

     Ya a bio filter. I have one on my previous 50 G. system but am trying not to use it. I want to see if i can get up and running without it.

 

    I will use that fish advice for now untill i can find some that might work in such a small space. It might just be suted for smaller fish.

 

   Thats a good thing to note about the airstone. The travel time would be for maybe 4 hours max. 

 

 

     Thanks for the suggestions and links.

[TCLynx]

Well there are super low density raft systems that don't use a separate bio-filter.  Like the friendlies micro system where you might use a 300 gallon fish tank (but only stock 20 fish) and have to 4' by 8' raft beds a small water pump and an air pump with air stones in the raft beds and in the fish tank.  Such a system is depending on all the surface areas in the system for it's bio-filtration.  As in if you drain a tank to transport it, letting that surface dry off or get exposed to lots of light is going to kill off your bio-filter.

So a raft system without a separate bio-filter that you can't transport with the water in it, doesn't seem like something you are going to keep alive and stable through transportation.

 

The beneficial bacteria lives on the wet surfaces not floating in the water.  There may be enough of the good bacteria floating in the water to seed a system with the beneficial bacteria for a reasonably quick start up (reasonably quick start up is in the 3-6 week range) but not enough just in the water to allow you to kill off all the bacteria on the surfaces and expect it to not require cycling up again.

 

Just seems to me that a transportable bucket of media as a bio-filter will make a demo system far more transportable unless you are able to leave the water right in the system and leave it running right on through transport.  Otherwise you would need to drain the system and load it into the transport vehicle and then re-fill it with the water and some how keep the water from sloshing out during the ride (tight fitting lids could take care of this but might be an issue for aeration unless properly designed.)  The plant raft would probably need to go into a different container with some water and aeration so that the raft bed could get a lid sealed onto it too.  Remember you want to keep the bacteria in the container alive as well as the bacteria on the bottom of the raft and you don't want to mangle the plants by pulling them in and out of the raft all the time, other wise you will only have tiny seedlings in the demo system which isn't all that impressive.

 

So which sounds easier?

[Pierre Riche]

          Thats some realy good thoughts, I appreciate the help. I have thought over allot of these issues and figured about the same when it comes to the actual moving and reinstallation of the system. 

        Even though the medium filled unit would hold the bacteria longer and safer I realy want to use the raft system. There are several challenges involved with the raft unit.

       The first is how quick can i get my systems nitrogen cycle established (ready to add fish and plants). The answer is, it depends. I'v cheated by adding some of my neighbors pond water. I also hooked up my 5G. bio filter taken off of another small system i have currently running. Maybe i'l even try to jump start it more by innoculating it with some benneficial bacteria.

      The second is can i break it down, transport and reinstall without losing a healthy bacteria collony. In this case i would agree with you on leaving as much water as possible in the tank and bed and keeping the raft plants moist. Thats a good point to mention about not letting the surfaces dry out. On that note i was wondering if i put some porous objests in both the tank and bed would that help. The thinking is to create areas where bacteria can cling to and thrive. Maybe even stapling a layer of porous material around on the inside in essence creating an internal bio filter! That would both help the bacteria grow and keep it moist and alive durring transport.

 

I added a photo of the system. the fish tank is below and can slide out when drained. The plant bed is above w/ an overflow standpipe. 

     Thirdly in the future i want to add prawns to the raft bed to live under the plants.

 

TCLynx said:

Well there are super low density raft systems that don't use a separate bio-filter.  Like the friendlies micro system where you might use a 300 gallon fish tank (but only stock 20 fish) and have to 4' by 8' raft beds a small water pump and an air pump with air stones in the raft beds and in the fish tank.  Such a system is depending on all the surface areas in the system for it's bio-filtration.  As in if you drain a tank to transport it, letting that surface dry off or get exposed to lots of light is going to kill off your bio-filter.

So a raft system without a separate bio-filter that you can't transport with the water in it, doesn't seem like something you are going to keep alive and stable through transportation.

 

The beneficial bacteria lives on the wet surfaces not floating in the water.  There may be enough of the good bacteria floating in the water to seed a system with the beneficial bacteria for a reasonably quick start up (reasonably quick start up is in the 3-6 week range) but not enough just in the water to allow you to kill off all the bacteria on the surfaces and expect it to not require cycling up again.

 

Just seems to me that a transportable bucket of media as a bio-filter will make a demo system far more transportable unless you are able to leave the water right in the system and leave it running right on through transport.  Otherwise you would need to drain the system and load it into the transport vehicle and then re-fill it with the water and some how keep the water from sloshing out during the ride (tight fitting lids could take care of this but might be an issue for aeration unless properly designed.)  The plant raft would probably need to go into a different container with some water and aeration so that the raft bed could get a lid sealed onto it too.  Remember you want to keep the bacteria in the container alive as well as the bacteria on the bottom of the raft and you don't want to mangle the plants by pulling them in and out of the raft all the time, other wise you will only have tiny seedlings in the demo system which isn't all that impressive.

 

So which sounds easier?

[TCLynx]

A couple things worry me from that picture.  First, wood is going to rot very quickly in contact with ammonia or nitrogen rich water so I hope it is well sealed with something that is fish and food safe.

 

Second, I see copper pipe.  Copper in a recirculating system is very bad for fish and especially bad for shell fish.  In general all metal except high grade stainless steel should be avoided in contact with aquaponic water.

[Pierre Riche]

      Interesting. No there's no sealer, its a wine barrel so i figured it's ok. Maybe not ay. and coppers no good either. bummer, i liked the look. 

     Thanks for the feedback.

[TCLynx]

Keep in mind that the oak is often perported to kill off bacteria (like in cutting boards) and this would actually be a bad thing for aquaponics since we are trying to promote a bacterial filter and the sides of the tank are your main surface area for your bio-filter.

 

You can get barrel liners designed exactly for turning wine barrels into water gardens.

 

And I would loose the metal plumbing, it isn't a good example to set with a demo system.

[Pierre Riche]

       Thats awsome, your a wealth of information. How would one know. Man i have some reworking to do but better to know that stuff now than later.

     Besides the oak issue my PH is serriously low (4.7)! ouch i think thats all the wine residue left over or maybe thats the oak also. I used baking soda but it did'nt budge. What do you use to bring back alkalinity?

[TCLynx]

Baking soda will raise the sodium level so I wouldn't recommend that much.

 

The tannins in the oak or residue from wine could both have an effect on pH.

 

In more normal systems calcium carbonate (lime, shells, coral sand etc) can be used to buffer pH however in your situation I suspect those won't move the pH quick enough and you have more than just pH to contend with now since bacteria quit working as the pH drops much below 6 usually.

 

Calcium hydroxide and potassium hydroxide can be used to raise pH but you have to be careful with them.  In a functioning system with bacteria, plants or fish you don't want to raise the pH more than 0.2 per day.

[Pierre Riche]

      Ahh, thats a good thing to know. So bacteria starts to dies off below 6 ph then and what would be the safe ph limit on the alkalinity side?

     Where can i get Calcium hydroxide and potassium hydroxide? I mean is there a household item that has it in it? I know that lemons are good to increase acid for ph down. Is vinigar good for PH up?

 

    Regarding the oak issue, i know of a fish safe nontoxic epoxy paint i can paint the inside of the barrels with.

[TCLynx]

Aquaponics pH Ideal would be about 6.8 I guess.  6.0 is a bit tricky since the standard pH test kit only reads down to 6 so it is hard to know if the pH is really way lower so I usually recommend taking action when the pH gets down to 6.5.  My big system is overly well buffered since I used shells as part of my media and that buffers up to 7.6 and my well water is natually over 8.  The bio filters work best between about 7-8 the fish are usually fine between 6-8 and the plants mostly prefer between 5.5-7. 

 

To Bring pH down, both vinegar and lemmon juice are acidic but they are also both somewhat antibacterial so I don't really recommend them much.  Since you don't need to lower your pH though I wouldn't worry about it much.  Just don't raise your pH too high and it won't be an issue.

 

Calcium hydroxide is hydrated lime, someplace like ace hardware would have it.  Not sure where you get potassium hydroxide.  I would be more likely to use potassium bicarbonate which can be gotten from brewing or wine-making supply places  Other options for slower raising of pH and buffering are things like lime, shells, coral sand, or basically any calcium carbonate but these are slow acting so I usually recommend adding things like chicken grit (crushed oyster shells or similar can be gotten at any feed store), shells or limestone chips in a mesh bag that you could remove from the system should the pH start getting too high.

 

The epoxy paint might be your best bet, just read the instructions carefully and follow them to make sure it works right.