If you regularly add anything to your aquarium like fertilizer for planted tanks, you know what a pain doing it every day can be. There are sweet precision dosing pumps available online, but they are expensive
DIY aquarium dosing pump setup
Here’s a list of what you’ll need (there’s a link to Amazon at the end of the article too).
- Scissors
- Small measuring cup to measure the dose you’ll need
- Aqualifter pump
- Airline tubing
- Air control valve
- Digital timer
- Bottle or other container
- Air pump (optional)
- Extension cord or outlet splitter (optional)
The basic setup is pretty simple. You just connect the inlet port from the Aqualifter to the bottle with air hose. Run tubing from the output port to the top of your aquarium and connect the valve. You can add additional tubing after the valve if desired. 
I recommend you do not put the tube in the aquarium water. When the power is cut off, tank water might siphon back into your dosing system and make a big mess. If you need to do it that way, add a check valve to your setup.
DIY Dosing Pump Calibration
Once you have everything where it’s going to go, it’s time to test and make adjustments. Close the air valve and then plug in the pump. Slowly open the air valve until your liquid starts dripping out. I used water during the calibration. Make sure there is additional space in the bottle for air to enter. If it’s perfectly sealed, it will create a vacuum and nothing will flow. Adjust the outflow until the setup dispenses the amount of liquid you want in the time span of 1 minute. Once you got it dialed in, put the pump on the timer and set the timer to come on one minute per day at the desired time. 
Now your dosing will happen automatically. Pretty sweet. One note, when you do the calibration step, it’s important to do it with everything in the place it will be permanently. If you test outside the tank and then move it, the difference in height or tube length might alter the liquid flow.
Add a mixing pump to dosing setup
Ok, I have to admit, this isn’t new ground, I found these tips online in plenty of forums. My addition is the optional steps I’m going to share now. 
I use dry fertilizer mixed with distilled water. As a result, things tend to settle. Since I probably won’t shake the bottle regularly, I need something to occasionally stir up the solution. That’s where the air pump comes in. All I did was plug an air pump into the same timer as the lift pump using an extension cord. Then I ran the tube into the bottle. Now, when the timer kicks on, so does the air pump. Since it’s just a tube in there, it generates huge bubbles which stir up the liquid just fine. To be honest it kind of sounds like the engine from a 1978 Buick when it’s running, but it sure gets the job done. I pretty much had the gear laying around already, so for just the cost of the Aqualifter I got a nifty setup that did the same thing for me that a much more expensive metered pump does. You wanna do this project yourself? Hit the link below for an Amazon list of all the stuff you’ll need. (I get a small commission for anything you might buy) Equipment List for Project
