Backyard Aquaponics
A place to discuss aquaponics

Yea for smaller pipes through buckets or barrels they are generally very easy to push through. A bit of water is often all the lube you need.

You are right to avoid soap around aquaponics.

Silicone can work but I've found for anything smaller than about 1 1/4" through a tank of 1/4" or less, spit is usually enough lube as long as the end of the pipe is pretty smooth. Even 1 1/2" I usually avoid messing with extra lubrication as long as the angle to push is easy.

You can also use rubbing alcohol as lubricant and it will evaporate instead of hurting the fish with residue, this is usually what I have used for the larger uniseals (2", 3" and 4") On the 4" uniseals I usually find that I have to bevel the end of the pipe and they are often a bear to get installed and if it is not an easy angle to push, I've sometimes found it takes monumental effort and usually going away for a while and coming back again later to finally get it installed.

I had little/no problem installing 4" uniseals in the 1000 gallon tanks that were half filled and sitting on ground level and installing the uniseal between waist and shoulder level since that was a good angle to push and the half full tank wasn't going to move with just me pushing against it.

However trying to install a 4" uniseal into a 1000 gallon tank sunk in the ground with the uniseal being installed below grade was quite a lot harder, you need to dig a big enough hole to get down in to push the pipe through the uniseal. for that job I was thinking I may have wanted to set up a threaded rod type clamp to see if using a clamp of some sort might have been able to pull the pipe into the uniseal better than pushing it. Will probably try that next time, just need to get some 1/2" threaded rod, large nuts and washers, a couple boards and some pieces of 6" pipe to arrange it all.

BUMMER DUDE!

Trying to beat the sun going down, on the last day for a long while that I would be able to work on this thing, I messed up the 1.25" hole for a Uniseal to pass a 3/4" PVC into my plastic sparklets bottle (swirl filter). Hole became jagged and oversize. I plugged the Uniseal for the 3/4" PVC in the 55 gallon plastic barrel with a cork, removed the swirl filter, (no fish yet anyways) and ran it for a few days till I figured out a fix.

I was able to cut a clean 1.75" hole that eliminated the smaller, jagged one completely. This hole fit a Uniseal for a 1" PVC pipe. I thought that this was going to be a fix, but after running 24 hours, it leaked about 20 gallons, as forcing that larger Uniseal (it was hard!!) had made small radial cracks in the thin plastic sparklets bottle where the uniseal penetrated.

So now, I have removed the swirl filter again- luckily I had the wisdom to install shut off valves in the PVC pipes exiting the 55 gallon barrels.

I don't think I can patch these cracks in the plastic sparklets bottle. But I dread to make a new one; I think I spent 30-40 hours making the first one! Of course, that is because I don't have the correct tools, and I used a LOT of tedious hand craftsmanship to fashion parts by hand.

Borrow a hole saw already sounds painful jon

My first, bad hole used a saw with a cylindrical saw blade. I was trying to drill my swirl filter while partially drained, but still hooked up to my aquaponics rig, and the saw was not easy to hold steady and it got out of control. All the other holes (successful) were cut with the item removed and under control. My successful holes used a rather scary adjustable fly cutter. Picture a center drill with a knife blade held out to it's side by an adjustable arm. This damn thing sends this blade spinning around the center drill. Scary!

a good hole saw with a battery drill is easy - it has a center drill bit that makes it not move around - of course you can also put the drill in reverse.

>>>>>HEY, I GOTTA QUESTION!!!<<<<<<<



Even though I don't have any fish, by dry-cycling with household ammonia, some of my vegetables have gotten HUGE!!!
My system is basically a NFT style. If I want to harvest a giant Bok-Choi plant, how do I clean out the roots that probably travel many, many feet around my NFT piping?

Unless you plan on eating the roots...

Don't bother cleaning them... just cut them off...

Jon, where ever you read that these systems run on a fish to plant ratio is dead wrong. You can not say i have 96 plants so i can have 24 fish, i am sorry to say. This will only lead to heart ache for you in the future.

What you need to say is, i can have x kilograms fish for every x liters of media. I think the usual quoted figure is something like 1kg of fish per 25 liters of media. I am sure someone will chime in with the actual numbers. In your case the media is your clay balls. You also need to keep in mind that the weight of the fish is at harvest time, not when you buy them.

Thanks RupertofOZ and rsevs3!

I did read that there should be a ratio of 4 plants to each fish. Now, I know that 8 tiny plants could not consume enough nitrate to balance the output of two large fish, but it seems reasonable that the quantity of fish (pounds), plants (pounds) and hydrocorn (pounds or cubic feet) should 'balance'.

I have about 1/4 gallon of hydrocorn sprinkled into the 12 small netti-pots in the horizontal track, and about 4 gallons in a dedicated bio-filter. I also added a fishtank bubbler into this bio-filter. I understand the bacteria like air!

In full operation, I hope to have 18 pounds of fish in 110 gallons of water and 76 plants. Right now, most of my plants are around the size of one human hand, but I have 4 or so that are the size of basketballs!

You are quite correct in saying you want your fish/media/plant load to balance. However, within those parameter, by far the most important ratio is the fish to media ratio. The bacteria living in the media is the most important asset in the system and you need to make sure you have enough of them.

Any thread you see where people are having ammonia or nitrite in the system the fish to media ratio is out. You will notice these threads are full of activity and quick action to save the fish. Any thread that you see someone has a nitrate reading then the fish to plant ration is out. You will notice no one bats an eyelid at these threads.

Yes you are correct, but one ratio is significantly more important than the other for a sustainable system.

Another reason the fish to plant ratio fails is that each plant is capable of taking very different amounts of nitrates out of the water. For example, a tomato plant will use significantly more nitrates than a lettuce plant. I highly doubt that four lettuce plants would be capable of using a platable fishes worth of nitrates.

Not trying to discourage you at all but i figured sorting it out now would be less discouraging than having a whole heap of dead fish.

Right, the bio-filter or media volume where the bacteria live is most important in figuring out how many fish a system can support. The plant ration has more to do with how long you can go without doing water changes if you have too many fish but still enough bio-filter.

Anyway, don't bother counting the media in the net pots in the NFT as filtraiton since it is probably minimal help you are getting there. It is the media in your dedicated bio-filter or media beds that provide you with the bio-filtration. For a system where solids go into the bio-filter or media beds, you want to make sure you have about a cubic foot of gravel per fish that might grow out to 1 lb. A cubic foot of gravel is about 7.5 gallons.

So, for your 4 gallons of bio-filter, I would recommend one fish that can grow out to 8 oz. If you are very successfully removing the solids from the system, you will be able to grow a bit more fish for that 4 gallons of media since there won't be as much competition among different bacteria for the oxygen. Basically if you have lots of solids breaking down in the system, there is more biological oxygen demand to not only convert the ammonia to nitrite then to nitrate but also mineralize the solids (break them down by other biological actions into the component nutrients as well as into more ammonia that needs to be broken down into nitrite then nitrate.) Leaving the solids in the system provides more nutrients to grow plants but it also requires much more extensive and well aerated filtration to carry it out. Flood and drain media beds do this very well provided there is a lot of it (like twice as much as the fish tank volume or more.)

Anyway, 18 lb of fish in 110 gallons of water is uh, probably a bit over ambitious, I would say 12 lb may still be pushing it unless you are a really expert fish keeper and have lots of extra aeration and circulation and good bio-filter. Your plants in NFT pipes don't really cut it as bio-filtration, they are only there to use up the nutrients so you really need to get enough bio-filtration going to support your intended amount of fish.

Buy or borrow the proper tools to cut the holes. A hole saw with a center bit is the way to go or your other cutter sounds like it worked, you just have to be very careful as you use it. I generally recommend drilling the center hole first, then put on the whole saw part. Sometimes it helps to start the track by running the drill backward. Make sure you have a good stance and brace the drill such that it can't bite and twist your wrist and mangle the hole. When drilling plastic it is important to let the blade or bit slowly cut the plastic, don't push or force it since that is likely to simply bend and crack the plastic and many type of plastic are not good candidates for gluing or sealing since glue and sealant won't stick anyway. HDPE can sometimes be heat welded to fix cracks but that is a tricky skill and the welds are rarely perfect.

Thanks for all your help! I am now convinced that I will need to remake my bio-filter, I am just not sure HOW, or HOW BIG!

This design that I tried building had no provision for a bio-filter. After I realized I would need one, I read about a commercial system of about 1,000 gallons, and he said that his 10 gallon bio-filter was more than adequate. I figured for my 110 gallon system, a 5 gallon bio-filter would be conservative.

Of course, I wasn't taking into account that this high tech commercial bio-filter used some kind of specialized plastic media (I forget the name), was in a sealed stainless steel vessel, was probably temperature controlled, and most certainly not made in his backyard with hand tools from hardware store items!

QUESTION #1:
I have two 55 gallon barrels to use for fish tanks. You said that 12 Bluegill might be pushing it. Would you agree that 10 fish (5 in each barrel) would be workable?

QUESTION #2:
Given the number of fish from the previous question, how big of a bio-filter do I need to make? I have one bag of hydroton I was planning to use. I have not found any home made bio-filters for NFT systems. Do you have any suggestions?

I would personally get a bed or bin of some sort to fill with media (hydroton, gravel, whatever) and put plants in it as well as using it as a bio-filter. Using media like hydroton or gravel is not as efficient at converting fish waste as using a fluidized bed filter or others of the commercial bio filters so for backyard systems it is often good to make sure you have about a cubic foot of media like gravel or hydroton to filter for each pound of fish you might grow. Since you wind up needing so much gravel bed, it makes sense to not only use the gravel as the bio-filter media but also as a place to grow the plants.

I think I know how constantly flowing NFT systems work. I also think I know how flood and drain media beds/media biofilters work.

I do not understand how to MIX a cyclic and a constant flow system!

Not sure what you mean by a mix of "cyclic" and a constant flow..