Poor Mans Auto Dosing, Take III

[Wasserpest]

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.

[Wasserpest]

Now since I got this working, I wanted to do something similar for my 10 gal tank. MagicMagni gets the credit for this method which I modified a little bit. The MagicMagni method has three shortcomings in my mind: The contents of the bottles are not mixed, pressure builds up in the bottle because the end of the lines is restricted, and it's difficult to adjust. So here is the product of a few hours toying around with drip irrigation parts:



Bought a 9.99 air pump with two outlets. The air line goes all the way down in the bottle, to get bubbles to mix the solution while it is running. There are four 1/2 gal drippers built into each pressure line, three are reducing the pumps output volume, and one is an open end which also "wastes" some air, and reduces the pressure buildup in the bottles.

Why is pressure in the bottles bad? Because the air volume is compressed much more than the solution, so if the bottles are almost empty, there is a long time of dripping after the pump turned off, until the air is all decompressed. So you end up with a higher dosing volume with an almost empty bottle compared to an almost full bottle. Not good.

Therefore I left the end of the fertilizer line unrestricted, this way once the pump stops the flow stops as well. Inside the bottle there is a check valve which prevents water from siphoning back into the pump. Like with the powerhead method, you just time minutes and mark the bottles to see how much solution is dosed, and adjust if necessary.

Here is the completed setup, ready to be connected to the timer:



I guess similar to switching from DIY to pressurized CO2, going from bi-weekly (me) or daily dosing to this automated solution feels great... (and is much cheaper than the CO2 switch). For those of you who prefer watching their tanks to mixing and squirting fertilizer, consider a similar setup...

[actioncia]

Wow this is awesome man. Okay so you use the apple juice bottle just to experiment that tube is where the dosing takes place.Do I really need irrigation parts? Regards,

[Wasserpest]

Got one reply!!!!! Appreciate it, man I thought I needed to type slower...

You are correct, the apple juice bottle was just to catch the water while measuring how much solution was dosed out of the bottles.

Here is why I used this array of irrigation drippers... The air pump puts out way too much air if it isn't restricted somehow. In other words, it would probably empty half of the bottle in one minute, instead of just a small volume. There are many ways to adjust all of that, this is just one suggestion.

Obviously it would be better to get a pump that lets you adjust output volume! But $9 for a pump with two outputs is hard to beat

[jgc]

Have been thinking that a second needle valve on my regulator could be used to preasurize an auto doser. could count bubbles in fert jug to adjust rate. Added benifit is the fert mix would be at near saturation levels on co2

[Wasserpest]

Hey, that's a great idea. Were you thinking of a continuous dosing setup? The possibilities are limitless... I see a JGC Method on it's way... Love it

[jgc]

was thinking, not sure if I will ever get arround to it though.
a 5mm bubble is about 1/15cc. If I could get the count down to a bubble every 4 seconds, that is still 1cc a minute - 1.4 liters a day (about a gallon every 3 days). If the needle valve can cut it more than that, it might work.

I am living life without a needle valve, but understand that this is asking a lot of one. Course if you are running a soloniod - that would really help things out.
---
please excuse the 1001 wags in that estimate. have to wonder how much solubiltiy of the c02 will mess with this idea. if c02 really does disolve as easy as one thread mentioned, this will not work at all untill the solution hits saturation. Regardless, if it does disolve easily, the drip rate will increase as saturation is approched. but would be for a wonderful experiment.

[Wasserpest]

A solenoid would fix these issues, but then we are almost out of the "Poor Mans" range.

[jhoetzl]

Darn, and I thought the coffee maker was going to get involved in this project somehow! (see first pic :-).

Nifty system/mods...

What kind of mix is in the solution bottles?

GW's stuff?

[actioncia]

Okay I can probably use air check valve to adjust air pressure since I do not have any irrigation parts. As for timer, it only need to be on for the time it takes to consume that amount of volume. For example, if it takes 5 hours to consume 5ml then that is the time you would set the time. No need to type slower just people have not dicover such good things. Regards

[Wasserpest]

Originally Posted by jhoetzl

Darn, and I thought the coffee maker was going to get involved in this project somehow! (see first pic :-).

Nifty system/mods...

What kind of mix is in the solution bottles?

GW's stuff?

SAECO rocks!! I am not going to convert it into a micro doser...

Working in a nursery, I have access to the macro nutrients. For micros I use Flourish & Flourish Iron. I don't dose that much, so it comes out to about the same $$$ if I get stuff from GW.

[Wasserpest]

Originally Posted by actioncia

Okay I can probably use air check valve to adjust air pressure since I do not have any irrigation parts. As for timer, it only need to be on for the time it takes to consume that amount of volume. For example, if it takes 5 hours to consume 5ml then that is the time you would set the time. No need to type slower just people have not dicover such good things. Regards

Typical check valves aren't good for adjusting tasks, since they block flow in one direction and let it through reversed.

The trick is to get something adjusted that low. Like in your example, 5 hours to consume 5ml, is going to be pretty hard to find something that doses that little volume in that much time.

Maybe there are airpumps that can be tweaked to output a relatively small amount of air. I tried putting mine on a dimmer, but that didn't seem to work. Perhaps there are pumps that allow you to increase the distance between the swinging magnet and the wires, therefore reducing the pump output.

[actioncia]

So, those irrigation parts are readily available in my local stores? Regards,

[Wasserpest]

Not sure what "local" means to you, but Home Depot and Lowes have a mind-boggling selection of them. You can get them for various drip rates (1/2 gal/hr, 1 gal/hr etc). So the possibilities are limitless.

In no way I want to say that using lil drip irrigators is the way to go. It's just what I had available, and it's widely available to many.

[Wasserpest]

It has been working very well for two weeks. Dosing very closely to the originally measured amount.

The only issue that I have is that there is some growth (fungus/bacteria) in the micro bottle. Any way to keep this to a minimum, without harming fish or rendering the micros useless?