Tuesday, 25 August 2015

First Forays into Aquaponics

Now that the turtle tank (minus the turtle) is up and running I've turned my attention to growing lettuces hydroponically using the aquarium water as the nutrient solution. The tanks has not quite completed cycling yet. The ammonia levels are almost back to zero and the nitrite levels have peaked but the nitrate levels are only just beginning to climb. This seems like a good time to begin germinating some seedlings so that in a week or so they will be ready to take up the nutrients from the water.

I constructed a raft, to hold three net pots just below the water level. The raft is actually suspended from the cross-brace of the aquarium lid. I will have to make this a little more turtle safe later on, but I want to see if it works first. Three days ago I planted red lettuce seeds about 1/4" deep into some 1" cubes of rockwool. The first shoots are just breaking the surface. You can only just make them out in the middle pot shown below.

It seems to me that the biggest risk is that the nutrient level in the aquarium water may not be sufficient to achieve true aquaponics growth rates but If I can grow even a modest amount of lettuce to feed to the turtle then that would make this project worthwhile.

Saturday, 15 August 2015

Sprung a leak

Following my last post about how I did such a great job of plumbing my DIY canister filter for our soon-to-be turtle tank, one of the joints sprung a leak.

The T shown below had a threaded cap on the top, through which I could funnel water into the filter intake hose so as to prime the system. The filter relies on the system being fully-flooded, meaning no air. To prevent air getting in I used plumbers tape (Teflon tape) and Vaseline to make a super tight joint.

Unfortunately I overtightened the threaded cap and sometime early on Sunday morning this happened:

Fortunately we heard it split and were able to fix it. The split allowed air to get in, which broke the vacuum which the pump relies on to pull water through the filter and push it back into the aquarium. So when the vacuum broke, the water stopped moving although the pump was spinning.

I've since spent the last week experimenting with alternative methods to create air-tight joints and prevent the gradual ingress of air into the filter. Left unchecked the filter would become less and less efficient as more of the water was replaced with air.

My latest attempt is shown below:

I'm hoping that by minimizing the number of joints and just submerging the intake hose in the water, the in-flow of the filter will be less restricted and that that in turn will make it easier for water to be pulled into the filter and less likely that air will be drawn in. We shall see. I capped the end of the tube with a 1" T junction. I used an 'X' of egg crate material (the same kind used for the lid) to prevent fish getting sucked in.

Earlier this week I acquired some new plants. I'm particularly pleased about the Red Ludwigia in the foreground and the Cabomba in the background. The Tiger Barb seem to love the new foliage.

Friday, 7 August 2015

Plumbing with the fishes - DIY Canister Filter build

Before I got distracted building a gate I was in the middle of building an aquarium. I bought a second hand 90 gallon tank and built an aquarium stand from laminated 2x4s and framing hardware. I'd also built the filter from 4" PVC waste pipe.

Two weeks ago I finally ordered the remaining parts to finish the build. Let's start by looking at the filter media in the canister filter. From top to bottom:

Filter Sponge - 12" x 11" x 0.75" This will catch all the big poops.

Filter Floss Pad - 10" x 12" - 2 pk This will catch all the little poops.

The internet is full of people arguing over the benefits of bio balls vs ceramic media so I chose both.

Loading the media into the canister was easy. The hard part was figuring out how to plumb and arrange the filter.

How not to position canister filter

Initially I had the canister filter mounted vertically with the top of the filter above the water level of the tank. This worked but very quickly filled with air and was really difficult to prime. The first design change I made was to mount the canister filter on a diagonal, behind the tank and below the water level. This made life much easier. Priming was simpler because the water actually wanted to stay in the canister. 

I'm using an Ikea shelf to support the canister and some large jubilee clips to stop if falling off. The return pump is very close to the output of the filter and the tubing is as short and straight as I could make it. The flow rate is remarkable considering the size of the filter.

The jubilee clip in the top left of the picture takes most of the weight of the tube  so that it stays in the tank instead of wanting to fall out.

At the other end we have a 4" PVC Clean-out fitting with a bulkhead electrical conduit  fitting PVC glued in place. A jubilee clip helps create a water-tight and hopefully air tight connection to the intake hose. For anyone looking for parts to use for this, Carlon make a Liquidtight fitting which can be glued with regular PVC pipe glue:

These parts are great although don't expect the washers to be of much use in this application. Just cover everything in glue.

DIY Canister Filter Intake Design

The intake could be as simple as a hose hanging over the side of the tank. It gets complicated only because:

  1. We want to stop fish and debris getting sucked in and blocking the hose.
  2. We need to be able to prime (fill with water) the canister filter using the intake hose.
Usually an intake is just a rigid pipe with holes drilled periodically along its length. The problem is to prime the canister filter we need to fill the intake hoses, the entire canister and the pump with water and as little air as possible. If we drill holes along the length of the hose it becomes a whole lot harder to funnel water into the filter.

My solution, after three iterations, was to use a T connection with an airtight threaded cap at the top:

This is made simply from 1/2" PVC plumbing parts. I used teflon tape around the threaded cap to make an even tighter seal. To prime the filter I can unscrew the cap and insert a funnel. Water will pour down the T, fill up the intake hose, forcing air out. This assumes that the other end of the T is capped off. I achieve this by adding a coupler below the water line which lets me switch between another PVC cap and the regular intake pipe with the holes drilled in it:

This is the piece I use to cap off the pipe.

This is the intake pipe that is used in normal operation. The coupler is below the water line so it can be a push-fitting. There is no need for this to be air-tight. These changes make it much easier to prime the filter.

Here are some more pictures of the finished set-up.

I made this simple spray bar out of the same type of fittings used for the intake

And here are some Tiger Barb that call this tank home.

Suction Cup Zip-Tie fasteners

I made my own suction cup fasteners to hold pipes in place by buying cheap suction cups like these:

And then drilling a small hole through the nipple and sliding a zip tie through it. You can use these to attach just about anything to the side of a tank.

Gate Construction Part III

This is the wrap up to the gate project I started back in May. I finished it in 3 weeks, working almost every evening/weekend. Here are some photos of the key steps along the way to the finished gate.

 At the end of the last blog post I had mostly finished building the frames. This was by far the most difficult and frustrating part of the entire build. Once these were glued and bolted together my Wife and I set about first cleaning and then staining the gate. I chose the Home Depot's Behr Premium semi-transparent wood stain. Reading reviews of wood stain on the internet is enough to make you give up all hope of finding a product that will work. I'm not sure but I suspect most of the bad reviews are a result of poor preparation and application. I have nothing but good things to say about this stain. The colour covered the pressure treated lumber nicely with only two coats. I tried both a foam brush and a regular paintbrush and both worked OK but the paintbrush seemed easier. As with all stains the hardest part is avoiding drips and excess stain from gathering in corners and at the ends.

It took the two of us the entire day to stain the gate frames and all the fence boards. The weather was beautiful so we were able to get both coats in one day.

5 Gallon pails and broken chairs were essential to complete this project

When we ran out of big things we used paint tins to keep the frames off the grass.

The fence boards were quite easy to paint in batches.

Over the next few evenings I fastened the fence boards to the gate frames with deck screws.

To make it easier and faster I built a drill template jig for attaching the T hinges to the frames. I made it from a 2x4 which I planed square and fastened one of the T-hinges to. I then clamped it up against the gate frame and drilled the holes in the gate frame. This was really helpful.

With the hinges in place and with some help from my Wife we hung the gate between the posts. There is no easy way to do this. It just sucks and you will loose your temper. All I can suggest is lots of different sized pieces of wood to use as shims and whatever you do, don't settle for anything less than level and square. You only get once chance to hang this.

Here's a close up of the gate.

You'll notice the centre two boards are not in place. This is deliberate and allows you to cut them to size once you know exactly how the gate is going to hang.

A few weeks later I filled in the gaps either size of the gate with some 2x4s, post hangers and more fence boards. Sadly I'm all out of stain.

Thinking of building your own gate?

If this article inspires you to build your own gate please leave a comment. If you are on the fence about building it your self, hopefully this convinces you to do it. I wasn't sure that I could do it but I pushed myself and stuck with it and now I have a gate worth the time and money invested in it.