Inspired by Marcels thread
about cheap autodosing, I started thinking about how to cut down the time to mix fertilizers and dump them into the tank. From reading the thread, Marcels method
didn't seem to be simple due to the problems with the head pressure.
So fast forward a few months
and onto the Wasserpest method
I started playing around with a little powerhead (AS606). While head effects its output as well, it is very easy to reduce these effects by using some kind of output restriction on the end of the fertilizer feed line. This builds up some pressure within the tubing, negating the change in head pressure due to the solution going down.
Anyway, you will need the powerhead, a digital timer, an empty gallon jug, and some tubing. Here's a picture:
To reduce the power of the powerhead, and get some good mixing, I used an X (was out of T's... lol) to branch off one airline that points downwards into the solution.
The next step is fun: you need a watch to time minutes/seconds, and then let it run and mark the reduced level on the jug after every minute. This is the amount of solution that will be dosed... You can see my marks on the jug. I ended up with 24 marks. This means, for the duration of two weeks, I can dose every day twice, with the exception of one day (Sunday... is my tank maintenance day). Of course I can change that later to one dosing a day, double the strength of the solution, and it will last 4 weeks.
It's easy to make adjustments by adjusting the diameter of the output:
Here is the completed setup with the macro jug on my 100 gal tank:
I made two of those jugs with identical pumps, one for macros, one for micros. It has been working for a week now, flawless... No long term experience yet, but I don't forsee any problems.