As promised, below is a short video which hopefully explains the new clarifier set up.
To summarize, the original clarifier was a swirl filter. It was made out of a 55 gallon barrel mostly buried in the ground. It worked fairly well in terms of trapping heavy particles (i.e., negatively buoyant particles) but I had no way of easily cleaning it. The only way to clean it was by temporarily pumping the water out and then scooping the sludge off the bottom. This was very time consuming, and inefficient.
In order to be able to clean it properly, the barrel should be cone-bottomed with a drain line attached. I have not been able to find any cone-bottomed barrels of a suitable size. There are some for sale that I could attach a drain line to, but they are much too large for my system, and I don't even think they'd easily fit in the space I have available.
This is the smallest available cone-bottomed barrel I could find. It holds 303 gallons and measures 1.16 meters across - much too large!!
I don't even want to think of the sized hole that would have to be dug to incorporate this thing.
Because of all this, and looking for something smaller, I decided to try and use a reconfigured 5 gallon jug, like the kind that go on those water fountains:
Placed upside down and cutting the bottom off, these have a built-in cone and an easy way to plumb a drain line in. I took one of these jugs, cut it in half, and drew the profile out on a piece of rubber (in this case an old dog house):
I then took a second jug, cut the bottom off, and inserted the divider down the middle. It was glued in place using Duretan. I clamped a hose onto the neck and attached a PVC drain line onto that, and then buried the jug from the cone-down into the ground.
The result can be seen in the video below:
This thing works OK so far. Maybe I will like it better with time. I am not 100% convinced right now but it is definitely better than the prior set up with the unclean-able barrel.
As for the plants, they're doing well, especially since the world didn't end on Saturday. Here's an update:
I decided to take some fish out of the system this weekend. The reasons for this are because a) the fish are ready to eat (that should suffice!) b) I have plenty of smaller fish in the system which actually grow faster and process more food by weight than the big fish, and c) I am actually worried about creating an overpopulation problem which could lead to system-wide collapse/death eventually. Granted, that would still be a few months off.
I'm only talking about three of the largest fish, mind you! There will be plenty left afterwards.
I lowered the water in the fish tank by moving as much as possible into the gravel beds, the raft beds, and into the sump. I set up a small but functional purge tank in an old fridge. Fish go in the purge tank for a few days (recommended is no less than 4) with no food. This results in tastier meat.
The videos below show the various steps involved, and three nice sized Tilapia in the purge tank at the end! This was a little more difficult than anticipated! I will have to get better nets for this in the future.
As for my swirl filter, I will update that next week. I put together a sort of clarifier using a 5-gallon water bottle. I cannot say yet if it works or not. It appears to be too short because there is just not enough head created by the jug to force the solids out like they should be. It does collect solids and I am able to take them out, but it is far from optimal. If I could only find the exact same thing but 5x bigger!
Sunday, May 1st, 2011:The Good, the Bad and the Ugly
Lots to update this week.I'd been away for two weeks except for a very quick visit last weekend that didn’t really allow me much time to look at everything closely.
The Good:
On the Good side of things, almost all the plants are doing great. The video all the way at the bottom of this update shows all the plants. The watermelon bed, which hosts two watermelon plants, has growth all over the place.The bed itself is not even visible anymore.The plants have made their way onto the fish tank cover and the floor and there are more watermelons coming out.On the other hand, the watermelons themselves appear to grow quickly at first but then the growth rate tapers off.None of the watermelons are ready and the largest ones do not appear to be growing much anymore if at all.Maybe this is normal, I really don’t know. I'll have to read up on watermelon plants.
On the Bad side, the watermelon plants are suffering from some sort of infestation.I noticed this started last week, but I wasn’t here long enough to even think about what to do about it.There is some sort of white/tan-colored, very small bug sticking to the leaves.They do not move unless you disturb them.They do not appear to eat the leaves.By that, I mean they do not leave behind leaves with holes in them.They do leave behind a black, very ugly looking film.Maybe they suck nutrients out of the leaves without leaving holes, but what do I know? The strange thing is, the leaves don't look unhealthy, other than having that sludgy film on them.
Here are the bugs and the film left on the leaves:
Upper Right Corner: White/Tan colored bugs visible. Almost Everywhere Else: Black film left behind by bugs.
Click on the image for a better view.
In any case, for lack of any better ideas, I sprayed the plants down with a molasses solution (just a 1-liter spray bottle of water with about ¼ cup molasses and a squirt of dish soap mixed in).Some bugs are repelled by sweat smells so maybe this will work.While spraying the leaves, I noticed the black film they left behind washed off pretty easily, so if the molasses doesn’t work, maybe a good spraying with the hose will get them and their trash on their way!
Almost all the plants planted last week seem to be doing well, with the exception of a single yellow-tomato plant in the gravel bed, which appears to be rotting at the base.This is what ultimately afflicted all the tomato plants that had grown in that bed previously, so that’s disappointing.I’ll keep an eye on the other tomato plants in that bed and watch out for the same symptoms.
The tomato plants in the raft bed are doin’ great.I wish I had taken pictures of the roots. That will have to wait ‘till next time.I filled the rest of that raft bed (raft bed 1) with other tomato plant types: cherry, roma, and more yellow tomatoes.If they all flourish, that’s going to be one hell of a bed!
Yellow Tomato Plants. I planted other tomato plants in the rest of this raft (not shown).
Background: Half-barrel cemetary from original design. I still might get some use out of those, so there they sit until needed.
In raft bed two, I planted new lettuces (shown in video).I bought the starters at the store.In raft bed three, the mustard plants are goin’ crazy, as can be seen here:
Worms:When I first learned about aquaponics, one of the key components presented was worms that would grow (and must grow) in the gravel grow beds.Worms play a key role in decomposing fish and plant waste that accumulates in the gravel grow beds. Worms both take advantage of this material and release the minerals therein for plant use, and also keep the gravel beds free from clogging.
What I never saw discussed anywhere was which kind of worms to use or where to get them.Little did I know that mattered!The first time I tried adding worms, I just dug around in the ground until I found some and placed them in my gravel grow beds.A few weeks later, hoping to find worms slithering all over my beds, I was highly disappointed to find not one!The ones I’d added died or escaped.
As it turns out, not all worms are equal – far from it!The type of worm that is best suited for decomposing waste and is used the world over for composting, is Eisenia fetida.That’s the scientific name for California red crawlers.Or in Europe, Eisenia hortensis. They thrive in rich organic matter, can tolerate high temperatures, and can withstand the flood portion of the flood and drain cycle without a hitch. These are the worms used in composting systems, vermiculture, vermicomposting, and it’s what those guys I first read about doing gravel-bed aquaponics use. However, it seems that in some places these worms will just crawl out of the ground and into your grow beds all by themselves.Maybe that’s how it works in Australia, which is where most of the aquaponics stuff I first read about takes place, but not here!In most places you will probably need to find someone that harvests these worms and buy them.That’s what I did.
And here they are:
They burry themselves in the soil, so you have to disturb the surface in order to get any kind of a
picture of them, of which this one is, I just realized, quite lousy.
I set up what is in effect an “inoculating nest” on top of each bed today.The nest is just a small plastic plant container (with those big drain holes on the bottom resting on the gravel bed) filled with worms and the material (worm compost) they come in, and covered with another plant container upside down (with the holes up, providing air).I am hoping they will make their way into the cool, dark, moist, oxygen rich, and waste-rich beds underneath.If they don’t, I will be incredibly disappointed to say the least.I thought I learned something here, so don’t let me down, my red, wiggly, friends.
This is a great site with just about all the information you could possibly ever want on red composting worms:Red Worm Composting.The worms make great home composting systems too of course.I set up two this weekend – one for the house and one for the farm.
It does not appear to be affecting anything (yet).From the swirl filter, water drains to the sump, where it is heavily aerated.I think the nasty gases produced by anaerobic minerilization get fairly well vented out in the sump.They certainly do not appear to be harming anything at this point.Anyway, I have a plan to tackle this but haven’t had the time to implement it yet.Basically, a better designed solids-capturing system that can be cleaned regularly I think will do the trick.The current swirl filter is just not easy to clean, so things that collect overstay their welcome and go anaerobic.I do think this waste can go into a nice vermicomposting system later on – something else to research.
