Overview of Autodosing Methods

[Wasserpest]

Over the past years, several people have introduced autodosing methods and more or less successfully used them. For future reference, here is an overview of these solutions, along with some personal opinions with regards to cost and advantages/disadvantages of each method. I will update this post as new ways are discovered, or edits become necessary (let me know if there are any errors or omissions). If you have questions about specific methods, please post them in the threads for that particular doser.




1) Autofeeder

http://www.plantedtank.net/forums/eq...ing-cheap.html

$: About $40 for the Pentair Aquatics Lifeguard feeder

+ Simple setup. Dry mix keeps nutrients from degrading.

- Integration into hood (sump would be advantageous). Moist air will clump fertilizer, might not work reliably. Fertilizer powder getting into the feeder will destroy the mechanics over time.

2) Test tube

http://www.plantedtank.net/forums/di...ro-dosing.html

$: Minimal

+ Extremely cheap. Very simple setup and fairly reliable dosing.

- Needs area of consistent high flow, like inside a filter compartment. Over time, biofilm can grow, or detritus can fall into the tube, reducing the amount of dosed fertilizer.

3) Syringe 1

http://www.plantedtank.net/forums/di...icrodoser.html

$: About $5 for mechanical timer, oral syringe and some small parts.

+ Good for very small doses

- Somewhat complex to build. Plastic syringes don’t last long. Dosing adjustment not very flexible. Needs strong timer motor.

4) Syringe 2

http://www.plantedtank.net/forums/di...fluidoser.html

$: About $10 for mechanical timer, syringe, checkvalves and some small parts

+ Easy to adjust in a small range. Minimal maintenance once it is working.

- Plastic syringes have limited lifespan. Depending on checkvalves, there could be some back-syphoning if the bottle is underneath the tank. Somewhat complex to build.

5) Airpump 1

http://www.plantedtank.net/forums/di...uid-doser.html

$: About $20 for an airpump, some tubing, and an electronic timer, $2 more if using checkvalves.

+ Very simple setup. Minimal maintenance once it is working. Very easy to adjust dosing over a fairly wide range.

- Difficult to get the needle holes to be the right size. Liquid (bubbles) remaining in the tubing might prevent refilling of the coil. Small changes in dosing depending on fillstand of solution.

(Here is a modified version of this!)

6) Airpump 2

http://www.plantedtank.net/forums/di...to-dosing.html
http://www.plantedtank.net/forums/di...-take-iii.html

$: About $22 for airpump, some tubing, checkvalves and an electronic timer.

+ Reliable dosing once the rate is adjusted.

- Mixed solutions might degrade over time. Changes in dosed volume depending on fill volume of bottles.

7) Aqualifter

http://www.plantedtank.net/forums/eq...sing-pump.html

$: About $12 for the pump.

+ Simple and inexpensive setup.

- The Aqualifters output is greatly affected by head pressure.

8) Peristaltic pumps

http://www.plantedtank.net/forums/di...ng-topoff.html

$: About $80 for one pump and an electronic timer

+ Reliable dosing, easy setup.

- Cost!

Here is a link to an excellent DIY peristaltic pump!

9) Gravity fed

http://www.plantedtank.net/forums/eq...ty-dosers.html

$: About $25 for the Kent unit and some tubing, ?? for an IV bag from your hospital.

+ Simple setup

- Difficult to place, unless a sump is used. Settling and degradation of solutions might occur.

10) Water Pump

http://www.plantedtank.net/forums/di...g-dummies.html

$: About $22 for a water pump, an electronic timer and some tubing.

+ Simple setup. Very reliable dosing. Minimal maintenance. Good adjustability.

- Solutions might degrade over time.

[dipan]

Really nice summary!

[plantbrain]

Great job thar!

Regards,
Tom Barr

[original kuhli]

I have an additional ideas that I've yet to test...

The central theme is using the constant outlet pressure of the CO2 system and a solenoid to pressurize a fertilizer bin and deliver a set volume of fluid to the tank/closed plumbing system. The costs would include solenoids for each of the two fert bins, the bins themself and checkvalves for each. This is the system I'd like to use on my tank buildup but I've not had time to test it.

Also, the failure of my solenoid open has made me rethink this...

[spypet]

*sigh*
shame my dry autodosing idea didn't make the cut.
as I spent so much time coming up with it

http://www.plantedtank.net/forums/eq...tion-here.html

[Naja002]

Good Job, Wasserpest! I see You've realized the short lifespan/value of the plastic syringes. I learned that with reptiles yrs ago, but always thought it was probably the soaking in alcohol that degraded them.

Did You ever get #2 (Test Tube) sorted out or are You still working on it?

I just bought 2 peristaltic pumps--which I think I will really like, but they are cost prohibitive for MTS! I think the Air-pump, water-pump and Aqualifter are probably the best systems--for the money! They offer A Lot of Bank-for-Buck

On the Water pump system--I say: skip the "powerhead" and get a small pump like a Via Aqua or Rio. My little Via Aqua 480 will pump about 59" head (straight-up) through 3/8"ID tubing---for only~$10-12. Reducing/controlling the flow isn't too hard.

Originally Posted by spypet

*sigh*
shame my dry autodosing idea didn't make the cut.
as I spent so much time coming up with it

http://www.plantedtank.net/forums/eq...tion-here.html

Hi Spypet,

I didn't even see that post until just now. Basically for dry dosing I think the Lifegaurd Auto-feeder beats anything else hands down. IMO, A lot of the things You listed either just won't work; or are way too expensive, put up too many stumbling blocks or both. Great Effort-Yes! But I don't think people that want to auto-dose really care whether its dry or wet. So, expensive dry solutions are pretty much out when we can have so much control via peristaltic pumps (x2) for under $200. With familiarity the air, water and aqualifter systems can be very reliable and offer Good control for --$25. Its Good to see that You are thinking outside the box--but its a tough challenge!


Either way, I've seen most of these develop during the couple of yrs that I've been around here---so who knows what we will see in a couple more yrs!

[Betowess]

Nice summary. Maybe a little low on price on water pump method.
The AS 606 is $16.49 before shipping from BigAls and a digital timer around $10.00 though I suppose one might find a better deal. Add in some hose and a flow control and your looking closer to $30 plus, IME. I spent ~ $13 each (shipping included) for a great flow control pincher from US Plastics, though I could have bought a much cheaper unit. That said, its all worth every penny since one's time should be considered valuble.

To anyone sitting on the fence, if you start autodosing, ya won't regret it!

[KDahlin]

It's never come up on my radar before. Seems like a great idea as I'm not that reliable for manual dosing.

[Wasserpest]

Originally Posted by original kuhli

I have an additional ideas that I've yet to test...

The central theme is using the constant outlet pressure of the CO2 system and a solenoid to pressurize a fertilizer bin and deliver a set volume of fluid to the tank/closed plumbing system. The costs would include solenoids for each of the two fert bins, the bins themself and checkvalves for each. This is the system I'd like to use on my tank buildup but I've not had time to test it.

Also, the failure of my solenoid open has made me rethink this...

I think that approach falls under the Airpump 2 category. Problem with this concept is the cost... You can get a dual outlet airpump for $10, while two solenoids and two needle valves will be quite costly.

[Wasserpest]

Originally Posted by Naja002

Good Job, Wasserpest! I see You've realized the short lifespan/value of the plastic syringes. I learned that with reptiles yrs ago, but always thought it was probably the soaking in alcohol that degraded them.

Thanks Naja The alcohol will probably do them in that much quicker. The problem I came across is that the plastic plungers start to warp and finally give in. Oh well, what do you expect for $0.30...

Originally Posted by Naja002

Did You ever get #2 (Test Tube) sorted out or are You still working on it?

Yes, that is working for several months now, and by far the most trouble-free system you can imagine. I have 3 test tubes (NPK) sitting in my AC Mini, I can even see the fertilizer level from outside through the translucent filter housing. I am now so confident with the dosing that I just fill up the tubes, the hole size in the stopper determines how fast they dissolve.

Originally Posted by Naja002

I just bought 2 peristaltic pumps--which I think I will really like, but they are cost prohibitive for MTS!

Lol, I just received two of their peristaltic pumps. It would be nice if someone would figure out how to DIY them using a mech timer. Maybe one of my next projects. All you really need is a round housing and some sort of roller thingy that fits inside there.

[Wasserpest]

Originally Posted by Betowess

Nice summary. Maybe a little low on price on water pump method.
The AS 606 is $16.49 before shipping from BigAls and a digital timer around $10.00 though I suppose one might find a better deal. Add in some hose and a flow control and your looking closer to $30 plus, IME. I spent ~ $13 each (shipping included) for a great flow control pincher from US Plastics, though I could have bought a much cheaper unit. That said, its all worth every penny since one's time should be considered valuble.

You could be correct, I used to buy them for about $12, but they have probably gone up since. Like Naja mentioned, you can buy any cheap Rio or such. Digital timers, last time I checked they sold them in Target for $8, maybe it was a sale... I never saw the need for industrial flow regulation, I just used one of those drip irrigation connectors, closed one side off with a heated knife, then punctured it with a needle until the right size hole is achieved. Or use mini air tubing connectors. In any case, you can probably find something in your spare parts box.

[plantbrain]

My issue is that I have to fiddle with stuff over the long term too much for it to be worth the trade off to get precise, accurate metering without going very $$$. While some methods work well on small tanks, they are not useful for larger tanks, thus scale is an issue.

I also have adversion to too much over engineering.
Some things are no brainers, automatic water changers etc, but I even avoid that going semi auto.

I feed my fish, some use auto feeders, but most do not, I suspect most of you do not as well?

May as well dose the ferts that way too. Takes a sec only, and you are there to feed the fish already.

Regards,
Tom Barr

[Wasserpest]

I know what you mean... If you feed your fish daily adding some (perhaps pre-measured) ferts at the same time isn't a big issue. I used to do that, and hated it...

The goal is to find something that you don't have to fiddle with. The water pump dosing is a very good example - cheap and easy to set up, and minimal maintenance on the long run. Every 4 weeks I refill the container, that's it. Running the pump for one minute a day does not wear it out, uses close to no energy, mixes up the solution, and is very reliable. I just can't see much reason not to do that, even for larger tanks.

I might be a little extreme, but I am having fun fiddling now to go near maintenance free for the long term. Looking at 3 of my tanks, this is what I am using:

100gal: (10) Water Pump for N+K, (4) Syringe 2 for Micros, manual for P. Will be using (8) Peristaltic Pump for Micros, and (2) Test Tubes for P.

36gal: (10) Water Pump for N+K, (4) Syringe 2 for Micros, manual for P. Will be using (5) Airpump 1 for micros and (2) Test Tubes for P.

10gal: (2) Test Tubes for NPK, (8) Peristaltic Pump for Micros.

This setup is/will be reliable, and I only have to spend maybe 1/2 hour every 4 weeks to check fillstands and replace mixed solutions.

[Betowess]

I'm with you 100% on the reasoning, and use your waterpump design with slight modifications. My only difference, and I haven't had a mold issue is, I put CSM + B and N & K in the main container. Manually dose P.

In the future I might by a pair of peristaltics (one for each tank) and dose Trace that way and put NPK in the container/water pump.

[unirdna]

Incredible, altruistic effort! I cast my vote for a "sticky".