DIY Brine Shrimp Hatchery
Every time someone asks me to to describe to them how to build a brine shrimp hatchery, I have to repeat the same instructions over and over again. Things get REALLY interesting when I’m trying to describe the most intricate parts without pictures. So… to save everyone all the trouble, I’m going to put it all together here. (Now with pictures!)
For those who are familiar with making soda-bottle BBS hatchers, you will note that I have included a couple of things into the design of the hatchers that I make for my own use. Throughout the description below, I will point out these features and why I implement them. There is not necessarily a right or wrong way to put these things together as long as it accomplishes its purpose, which is to hatch brine shrimp. Feel free to modify or improve the design in any way to suit YOUR convenience level and your preferred ease of use.
You are going to need :
- 2 x Two Liter soft drink bottles. Clear ones are best. (Why not just use one?)
- Some 1/4″ airline tubing.
- 2-part epoxy. I recommend the quick setting kind.
- Scissors that are strong and sharp enough to cut the plastic bottle.
- Blue painters tape (or any tape you have on hand. I use blue tape because it is easy to remove.)
- Drill with 1/4″ bit plus any other bit larger than 1/4″ (Not shown above).
Putting It All Together
Step 1: Cut one of the bottles in half, dividing it such that the top portion is as equally tall as the bottom portion. Discard (or recycle) the top and retain the bottom half as the base. (see pic below).
Step 2: Cut the second bottle in the same way as the first BUT instead of dividing the top and bottom equally, just cut off the very bottom of the bottle. Cut it at the location where the the crinkles at the base smoothes out into a cylinder. At this location, the plastic is quite thin and easily cut. If you try to cut it at an elevation that is too low, the plastic is too thick and not easily cut. Save the top and recycle the bottom. (see pic below).
Step 3: Now take the top from step 2 and invert it into the bottom from step one. Your setup should look like this:
Make sure that you have about 1″ of clearance between the bottom of the bottle screw cap and the top of base. This is to allow some space for the airline tube to make the bend from the bottle cap to the base (this will be clear to you in a little bit, when get get to the airline tubing part). If in the small chance that you don’t have enough clearance because of crooked cuts or whatever, then go to the store and buy another bottle of soda. Drink the soda, and try step 2 again, this time make the bottom portion taller.
Step 4: Using a drill and a drill bit that is larger than 1/4″, drill a hole through the corner of the lower section in the “valley” between high points of the base (see pic below).
Ensure that the hole is large enough for the airline tubing to comfortably pass through it.
Step 5: Now we turn our attention to the bottle cap. Switch drill bits to a 1/4″ dia one and drill a hole through the middle of one of the bottle caps (see pic below).
Step 6: Pass the airline tubing through the cap so that it protrudes by 1/16″ to 1/8″ beyond the inside of the cap. (See Pic Below).
Step 7: Time To Test Fit! Keeping the airline tubing attached to the bottlecap, gently screw the cap back onto the top of the bottle which we obtained from step 2. Then pass the other end of the airline tubing through the hole we created in the base in step 4. Your setup should look something like this.
Note that we have a gentle curve in the airline tubing emerging from the bottle cap and through the hole in the base. If there is not enough clearance between the bottle cap and the base, you will notice that the airline tubing is NOT curved gently, but in fact BENT (kinked)! This causes the walls of the airline tubing to collapse at the kink, causing a constriction in the tubing. If this happens, you can try one of two things:
- Drill another hole in the base below the first hole and hope that this provides enough of an angle to prevent the airline tubing from kinking. OR…. (as previously mentioned in step 3)
- Go to the store and buy another bottle of soda. Drink the soda, and try step 2 again, this time make the bottom portion taller.
Step 8: Now that everything has been test fitted and we are happy, time to permanently join the airline tubing to the bottle cap. Leaving the airline tubing threaded through the cap and the cap screwed onto the bottle, invert the bottle on the table so that it is stable. The bottle cap (and airline) should be facing upwards like this:
Then take the blue tape (or any tape you have available) and stick it around the bottle cap to create a mold into which we are going to pour the epoxy. (see pic below). Obviously you don’t just squirt epoxy into the mold directly (like the picture shows). You mix it up somewhere else (like a little paper cup) and then pour it into the mold. The pic below shows WHERE the epoxy is going to go. Fill it to about 1/4″ to about 1/2″.
Don’t worry about the airline tubing drooping over he edge of the tape (as shown in the pic below). In fact, this helps to preserve the gentle bend in the line which we will need when we assemble everything later.
After the epoxy is set, peel away the tape and you should have a nicely molded epoxy cap. Here’s a pic of an old one that i did a while back. You can see the epoxy has yellowed (this is inevitable). If you find this repulsive, then by all means used colored or black epoxy.
It’s pretty much done! Assemble everything back together as shown in step 7 and you are in business. However, after many many times of accidentally flooding the kitchen counter when the power went out or perhaps forgetting that the airline was unplugged from the pump and allowing it to drain onto the kitchen floor, i would recommend the following simple improvement.
Step 9: (Optional) We are going to create a little airline clip (or clamp or holder or whatever you want to call it) in order to hold its highest point of the airline above the water level, so as not to allow the contents of the bottle to drain when disconnected from the pump. Simply cut a vertical 1″ slit down the top edge of inverted bottle. At the bottom of the slit, cut (or drill) out a 5/16″ hole. It should look like this:
What is the purpose of this? Well… you thread the airline tube through it! (see pic below). The slit allows you to quickly either slide or remove the airline tube from its holder without having to actually thread the end of tube through the hole each time you need to install or remove it.
This is the end product. Notice the location of the highest point of the airline tube. As long as you don’t fill the water above this point, you don’t have to worry about accidental drainage. Plus, harvesting of BBS is as easy as removing the airline tubing from the clip we just created and allowing the contents of the bottle to drain into a brine shrimp net that is held at a lower elevation. (i’ll replace this blurry pic as soon as i get back from Singapore… i promise!)
1) Why Two Bottles, Not Just One?
Yes. Yes… I know, why should I bother with two bottles as compared to just one bottle? Like I said before, there is no right or wrong way to build one as long as it accomplishes its job of hatching brine shrimp. I used to use a single bottle for the longest time before finally switching to 2 bottles. This improvement has to do with functionality. The main reason is:
Increased capacity of the hatching chamber.
Most single bottle designs out there call for cutting the bottle in half, dividing it such that the top half is exactly the same height as the bottom half. Have a look at the two photos (same ones as above) below. It is quite evident that dividing the bottle exactly in half produces a chamber that is smaller than the one using 2 bottles. Having the capacity to hatch large amounts of BBS is quite beneficial to serious breeders. But if you have no need for the added capacity, then by all means, stay with a single bottle.
The second benefit for the increased volume is that chances are, you will have some added distance from the surface of the bubbling saltwater and the top of the hatchery. This means that you will be able to cut down on the splashing. Those of us who brew brine shrimp often know the amount of salt which the bubbling water is able to toss overboard, creating a salty mess on our kitchen counter.
This first pic shows a single bottle divided in half. Note the size of the “upper” part.
Now look at this next picture which uses two bottles in the finished design. The bottom is sliced off in order to maximize the size of the top part of the bottle, which will eventually be the hatching chamber. Notice how much more capacity that we gain?
2) This is NOT a perfect design.
There are pros and cons depending on our usage needs. There is always room for improvement. If people don’t tinker and experiment, then we will never have anything new out there. If we think about it, whoever was the first person to look upon a 2L soda bottle and say “holy cow… i think this would make a great BBS hatchery!” was thinking outside the box. Happy Tinkering!