Brian's system so far

Brian Fanner

Hi all. I discovered aquaponics about two weeks ago while researching what type of fish I could stock in my farm dam and was hooked. I have begun building a system. I had an old enamel bath tub lying around and thought it would make a fine FT. Afriend of mine wes growing lettuce on a wall hydroponically using pvc guttering and a cheap water feature pump so i figured I would incorporate that in my system. Here is a pic of the bath with the guttering.

Brian Fanner

Ok... try the pic again.

TCLynx

Hay there and welcome!!!!

You do have a little bit of reading to do to get caught up. There is a key element you will need to add there. Filtration!!!! See the plants use nitrates but the fish produce ammonia and solids. The solids can get all gunked up around plant roots and cause problems and the ammonia needs to be converted via the nitrogen cycle into plant usable nitrates (there are a few steps in that process.)
Anyway, if you read through the Basic Info and Useful info sections of the forum pretty completely, you will have a better handle on the parts of an AP system. Then I suggest looking for some examples of member system threads that are a bit like what you want to do so you can find out the pitfalls and ways to avoid them. There are gutter type systems out there, usually called NFT, and they can work but they do have their special requirements.
Once you get through doing some reading, you can search or ask for some links to threads with NFT pipes or gutters. My system thread even has some but they are only a small addition to a mostly flood and drain gravel bed system.

Welcome, you are hooked now :cheers:

Brian Fanner

After reading the topic about fish and problems they have I noticed there was possibly a problem with the bath tub as the enamel is not perfect and could end up leaching toxins into the water killing the fish. So I decided to ditch the bath. I had this old fibre tank laying about the farm. The top was broken so i figured it would make a good tank. It will hold a lot more water than the bath and no leaching problem. I got all my extension cords and linked them all together and rolled the tank as far from the barn as I could get it. I donned my best dust mask and got out the baby grinder with one of those really thin cutting disks on. The wind was blowing pretty strong away from the house and barn and I proceeded to cut the top off the tank. Why all the precautions you ask? It is a fibre tank, pretty old and I suspect it may have asbestos in it! The dust actually blew away as I cut soI figure it all worked out and was safely handled. All Those asbestos brake shoes I replaced when young (and idiotic (shudder)) before they outlawed them would have done the damage already! Anyway now I have the makings of a great FT about 1000litres!

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Brian Fanner

Hi TClynx. Thats what that plywood box up in the corner is all about. I was wanting to do a couple of flood and drain GB's along the top of the wall. The problem I was having was the ratio of GB to FT and how to pump the water. Anyway now that I have a much bigger tank I am thinking much bigger GB's will be required! Great for more planting

.

Brian Fanner

The inside of the Tank is a bit dodgy! When I scrubbed it out parts of it where kind of rotting away releasing slimy fibry stuff! It is now dried out. I have some very good qualiy epoxy resin on hand and was thinking to give it a good coating of that to seal it up inside. This epoxy is pretty inert once set up so I figured it would be fine. The other option is a waterbourne bitumous sealer stuff for koi ponds but as I intend eating these fish the bitumous based stuff will probably not be a good idea. Any thoughts?

TCLynx

Ah, there ya go then.

Tip, for more gravel grow bed and to avoid big fluctuations in water level, you could try something like a "gravel filled sump" idea. That would be to set up the fish tank so it overflows into a gravel filled container next to it and slightly lower. Have a place in that container where the gravel is held back and place the pump in there to pump up to the higher grow beds which can drain by the gutters back to your fish tank. That would be kinda like a CHIFT PIST system sorta. The container on the ground next to the fish tank would probably have to be a bit bigger than the total volume of all the grow beds along the top of the wall.

Brian Fanner

For grow beds I am going to go for 2 plywood boxes 1.5m by 80cm by 30cm deep with plastic liners which would give me 720L of grow bed plus a bit in the lettuce gutters. I am wondering if one has say for example a 300L grow bed full of gravel, how much water does it take to flood it? How much water am I going to lose from my tank flooding 720L of GB? Oh dear. I see a timer and solenoid valves and and and......

I have a reservoir... It contains 50 000litres of water! I wonder how many GB's I would neeed to turn it into a aquaponic FT :shock:

TCLynx

We generally estimate that it takes about 40% of the volume of a grow bed to flood it (as in the gravel generally takes up 60% of the space.) This is only an estimate since it will vary depending on the kind of media and such. I usually tell people when sizing for a sump in a CHIFT PIST system, the sump needs to be at least 50% of the volume of all the grow beds plus some.

Beware putting any gravel in the gutters!
Here is a good system thread to read and it will explain why gravel filled gutters might not be the best choice long term.http://backyardaquaponics.com/forum/viewtopic.php?f=18&t=2218

Brian Fanner

Thanks TCL. I gather from the thread that there was not enough filtration in outbacks gutters. The thread is a bit long so I have not followed through it all the way to the end :cyclopsani:

. I am planning to have the water about 2 inches deep in the gutters using short standpipes and float some polly rafts in them for the letuce plants. I had the water running through the gutters with the tub and with the water falling about a foot from one gutter to the next creates a lot of air bubbles in the water in the gutters. Kind of like 3 waterfalls in a row. This would be good for the lettuce and fish, right? I have another tank which is also not in good shape on the top and am going to cut the top off that too and use it for the grow bed at the top. I like the sump idea but then I would need yet another tank

. I would then have an overflow from the tank into the sump. I would pump using a pool pump from the sump on a timer to flood the grow beds. The water would then drain from the grow beds into the gutters and flow back to the tank which would return via the overflow to the sump. Problem: What about all the solids in the bottom of the FT? If it overflows from the FT to the sump from an outlet at the top there would be nothing removing them

Schematic follows

Brian Fanner

If one has a really deep growbed full of gravel one would have less planting space but a very good biofiltre for removing harmfulls. Am I right here :?:

How important are the veg or is it more to do with the small growing biofilm organisms in the gravel. I am not desperate for planting space as I have a large veg patch going already and plenty of water to irrigate

RupertofOZ

The plants complete the nitrogen cycle... removing the nitrates which would otherwise build up over time in the water... thankfully, plants thrive on nitrates... :wink:

TCLynx

Since you have the gutters, that provides extra planting space but it doesn't provide extra bio-filter ..... so having some extra deep gravel beds would make up the difference in bio-filter.
I personally think extra deep flood and drain gravel beds are a great way to go.

As to how to get solids off the bottom of a fish tank using an overflow. That would be what we call a SLO drain or the drain formerly known as venturi drain. Here is a picture.

and here is a thread of diagrams that might help answer some other questions.
http://www.backyardaquaponics.com/forum/viewtopic.php?f=11&t=5311

Back to the gutters and you had said something about using gravel in them. The problem with gutters with gravel in them and then plants with roots and perhaps some solids, eventually there isn't a whole lot of space for water to flow through and overflows can happen. Heck, even in pipes or gutters without any gravel, plant roots often get big enough to block a lot of the flow and even cause overflows. I regularly have to yank out the basil growing in my NFT pipes and drastically prune the roots.

Brian Fanner

Thanks TCL. I saw pictures of those and was wondering what was happening. Now I know! I did try and put some gravel in the gutter right at the beginning and even clean I saw that I was going to have flow problems, so its clean gutters with rafts and lettuce. Painted out the tank with resin today, but the other tank I was going to use for a grow bed just broke op when I rolled it over so I guess its the plywood with liner again.

Brian Fanner

I have calculated that the tank holds 600 litres of water, so I need 600 litres of growbed. I have been hunting about for suitable grow bed containers but nothing great so far. As this system is going to be in a space that I would like to look nice I am not too keen on the blue barrel option and was thinking to build grow beds and tank from brick and then line or seal them with something. We have a product here called Superlaycold which is a waterbased emulsion bitumen based stuff. it says on the tin for koi ponds but must be allowed to dry for two weeks before adding water if used for this. I have a book out from the library on hydroponics and they built growbeds from brick and sealed them with butumen but I am concerned about the safety of this as i am concerned about the bitumen being toxic. Can any give any advice here. The other option is to line them with plastic pondliner.

I have learnt about a free source of fish. I was hunting about for tilapia in pet shops but nobody had them. I then was told that the pond behind the local shopping centre was full of tilapia. I went to investigate and it is packed to the max! So I have constructed this experimental trap to see if it works. Made from a 25l container and a coke bottle cone for the fish to enter and hopefully not escape. Do you recon it will work?

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