I'm more happy with this than any other aquarium I have ever made. Some information: Current inhabitants, 5 juvenile white cloud minnows. Total cost: about $80. Dimensions, 3 feet long, 8 inches square at the ends. The pump is a 710 gallons/minute. It takes between 9 and 13 seconds for a floating object to drift from end to end along the surface.
Sorry I didn't get more pictures of this process. I found some glass shelving at a yard sale and got it for $5. The 3 shelves were 8 inches wide and 3-4 feet long. I also got some painters tape and silicon. I used GE I (you want I, not II) and made absolutely sure it was NOT mold proof. The mold proof stuff has an additive in it.
Constructing the aquarium
I got my glass pieces cut and the edges ground at the local glass shop for $15. Two end pieces and three long pieces. Make sure you measure everything closely before getting it cut! And don't forget to account for the glass thickness. Your end caps will need to be cut to account for the thickness of the front and back panes. Also make sure your glass is thick enough in the first place. Skinny window panes ain't going to cut it. This was shelving though, and nice and solid. There are some good guides to constructing an aquarium online, link below. I won't go into the details myself because I didn't take pictures. You need a lot of hands to hold up the sides while gluing them.
A word of advice: the pressure exerted by water depends entirely on depth, so shallow tanks are a lot easier to deal with than deep ones. Had this tank been deeper, I would have considered a cross brace.
Honestly I'd love to have used a 12 or 22 gallon, I'm kind of pushing the lower size limit at 8 gallons.
Scraping of excess silicone
I prefer to overdo it a bit on the silicone and trim later. Fortunately, a razor will take it right off.
Getting the rockwork
Good quality rockwork accounts for my success as much as anything here. I'm lucky enough to live near road cuts will all sorts of good stuff. I used this chunky slate. Here it is in the wild…I gathered up broken-off pieces along the road.
Cleaning the rocks
Rocks come from the ground so they tend to be covered in dirt. So I washed them
Some preliminary planning
What makes good rockwork? It depends on the look you want. Rock (like this) with lots of fine detail will make your tank appear larger than it actually is. Rounded smooth rocks look more like a close-in to the bottom of a stream.
Still, there are some rules of thumb. Limit yourself to one type of rock, and your tank will look much more cohesive. I even arranged my rock so it all slanted the same way so it looks like pieces of the same underlying geology. If you have half-dozen different types of rock your aquarium will look more like a geology collection. But hey, if that's your thing go for it.
Cutting the slate
I wanted to hide my pump. The standard way to do this would be to use black acrylic, and that would have looked nice. But I didn't have black acrylic on hand. I DID have some slate tiles though. I figured, why not try it. Unfortunately they were 12 in and I needed 8 in squares.
Cutting the slate
So I had to cut them down. I used a fine-toothed saw to make the original grove, and then periodically thereafter to help clear out the cut.
Cutting the slate
I used a screwdriver and hammer as a chisel to chip away at the slate. Note you are not trying to just wedge through it, but to chip out small bits a layer at a time. I had the best success coming from both sides alternately.
Don't blame me if this screws up your screwdriver and saw…worked for me though.
If all goes well your slate will eventually crack in two down a nice line.
But don't rush it
However if you go too fast and try to crack it apart before it's ready, this will happen
The guts laid bare
Here's the first draft of my basic plumbing arrangement. You can see the pump on one end behind my open-cell filter-foam, then the pipe running to the far end of the tank. This kind of filter, with one end of the tank blocked off by foam, is called a mattenfilter. It was originally from Germany, as you might gather.
I added the rockwork like so. Everything is arranged to slant downstream, adding to the sense of movement. There are two pools and a narrow choke point, to produce areas with faster current and areas with slower current.
Adding the water
So I added water and fired up the pump and….water flew everywhere! 710 gph coming out of 3/4 inch pipe has some kick to it. Too much kick to stay in the tank, and it didn't look right. I needed to slow down the velocity while keeping the volume. So I had to drain it and take everything out again. Such is life.
There are at least two ways to slow down velocity…increase the cross section the water is flowing through, and add obstructions to make it bounce around and change direction. $10 of parts at the hardware store let me do both! Water comes up from the bottom and goes into a 1.5 inch pipe. It keeps going straight up the pipe and hits the top, which is blocked off with a screw cap. then it has to go back down and out the front opening, at a right angle to its previous direction. This produces a really nice, large volume but low velocity flow with some nice turbulence.
Here's where we are now, all the basics are done but it needs a bit of polishing. I had also added some gravel at this point. Note that the gravel matches the rocks nicely (It's actually eroded from similar rocks) and it's burying the bottom of the rocks. This makes them look more firmly emplaced, like they are part of some underlying structure rather than just dropped in the tank.
Plant cover for the filter
Plants take up nutrients that result from fish wastes, so having plant roots dangle into your water can help keep it cleaner. I had a nice patch of baby tears I decided to use for this purpose. Also, mountain streams don't naturally have a lot of plants in them, so this let me get more green in my tank without actually having it _in_ the tank. I made a mesh box or tray.
Tray in place
Here's the tray resting on top of the pump. It fits quite snugly.
Washing the plants
These were grown in dirt but should do fine mostly free-rooted in water. I had to was off most of the dirt to keep it from clouding my tank.
And from the side
The plant should grow and spread to cover up the sharp edges, which will make it look nicer.
Just some final shots
Note how I've covered the bottom edges and joints of the rocks with sand and gravel. It hides the fact that they are separate pieces.
It's fun to watch the fish zoom up and down this narrow stretch
Fish like to hang out in the strongest part of the current, but they can and do occasionally go down to the calmer areas of the tank.