The Planted Tank Forum - Reply to Topic
Thread: Cheap DIY liquid doser Reply to Thread
Send Trackbacks to (Separate multiple URLs with spaces) :
Post Icons
You may choose an icon for your message from the following list:

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

  Additional Options
Miscellaneous Options

  Topic Review (Newest First)
01-06-2011 06:34 PM
Wasserpest My guess is that only the OP has gotten it to work reliably.

I'd suggest you look into peristaltic pumps. The "water pump dosing" might work as well, a bit cheaper, with the added benefit of agitation of the solution.

Check out my signature link for various autodosing methods.
01-06-2011 05:56 PM
Travis32 Hello, I am looking for a good 2 part dosing system that's cheap and I don't mind if it's a relatively simple DIY project. I found this using Google. Does anyone know if they have gotten this fairly well ironed out or is there still significant issues with this design?

I'm having to dose a fairly significant amount of calcium. Approximately 2 - 3 cups per day of calcium chloride to keep it at 400. Alk remains stable with around 2 to 3 tablespoons of baking soda per day. If I ever go out of town I'll need to auto dose alk also in a dissolved solution. That's in addition to 1.5 gallons per day of top off kalkwater!

In a 125g tank with 30 gallon sump.

I read most of the posts and some say it works, some say it doesn't. I'm not looking for overly accurate, just something that would keep up with my alk and ca depletion on a weekly basis.
03-26-2010 04:44 AM
tyler79durdan hmm, still cheacking doses... still averaging 10 ml on a supposed 15ml dose. Its going down!
03-25-2010 11:45 PM
sparkysko I'm saying that it works fine while testing by blowing through the tube, but when you hook it up to an airpump for a minute then additional unwanted liquid enters the coil from the fill hole making it difficult to get an accurate dose.
03-25-2010 07:47 PM
tyler79durdan I really dont know WHAT YOU JUST SAID...

But it worked with a very small hole in the T. I noticed that this hole was the most important, as it really effected how fast it doses and how fast or slow it fills. Still working on the tubing refill cause it filler 15ml twice in an hour, then it filled 7.5ml once, then 12ish the third time. As long as it at least doses 11 average over a week of tri-weekly dosing, hmm I dont care as long as it doses something. Welcome to my world!


But Id guss this really doesnt matter since im changing water weekly!
03-25-2010 07:26 PM
sparkysko I built one too. I didn't understand the issues by just reading..

I haven't been able to avoid a venturi effect on the 'fill hole' at the bottom of the coil. This becomes a problem when you're using a timer that has a minimum of a 1 - 15 minute cycle. Unfortunately I think the venturi is more 'random' that reproducible, and I'm not sure if it can be calibrated with the venturi issue.. I tried adding valves/etc on the fill hole to adjust the venturi, and to keep it away from the coil, but it didn't help..

Instead, I dug out a bunch of the $1 automatic plant watering machines "Green Genius" that I bought at big lots on clearance. They're battery powered, but they have a dial to specify frequency of dosing (i'm using 2 days) and quantity in ml...

Prior to that I did some testing on water pumps, and dug out and calibrated a bunch of 4$ Cascade filters they had on clearance at Petsmart. Used epoxy putty to attach 1/8" hose to the outlet. Consistently within about 5% accuracy over the course of a minute..
03-25-2010 05:35 PM
tyler79durdan It works great! Here are my photos...

All it took was a little patience, 2 liters of spilled cool-aid, a broken t, and 65" of my tubing... Iv got a digi timer so Im gonna try it
05-20-2007 08:16 PM
The one negative I saw with the Eheim liquid doser is the amounts it can handle.
I could see a few more negatives... first and foremost, the cost. While one of them doesn't hurt too much, in my case I would need quite a number to supply traces (and maybe PO4) to all tanks. With some easy shopping, I can get a dual output airpump for around $10.

Keep in mind this is a hobby... time spent tinkering with things is something that I don't consider lost, and don't want to do without. Of course, if you apply your hourly wage to the time playing with tubing, you might be better off just to order the Liquidoser.

Another dealbreaker (for me) is that it has to sit on the tank rim, unless you have a sump. I like to cover my tanks as completely as possible, and use a slim canopy that just so fits some T5 bulbs with reflectors. Don't wanna have anything stick out.
05-20-2007 07:57 PM
dennis The one negative I saw with the Eheim liquid doser is the amounts it can handle. You can do a max of 1ml, 8 times a day (providing I am reading the literature right). In my case, that is not enough to handle my trace supplementation. You should be able to mix all your macros at a concentration that would work with but it would not be enough for me for traces.
05-20-2007 04:41 PM
JulieJeffers Looks like great idea.

All in all after the time spent shopping and fabricating, why not just get one of these?
Iím not being critical; I want to set up something like this and am looking at the pros and cons of each option.

05-16-2007 02:22 AM
dennis Walmart has Brinks brand digital timers for $8.73. They only have one on-off setting but they work in minute intervals so its perfect. The price is right also. I've done a lot of playing with the concept for the original topic to this thread, as well as magic's AirDoser and Wasserpest's powerhead method.

I'll start a new thread of my own for further updates.
05-15-2007 03:03 AM
dennis I think this would work perfectly fine if a minute timer can be found cheaply. Because large coils of tubing do not seem to work well it seems adequate to dose only in the 5-10ml range for short periods. I may be able to adjust that by playing around with large "chambers" in the solution bottle. Also, a cheap timer capable of minute intervals would make magicmagani's doser a good solution for toping off a little also. I'll hit Walmart or Target tomorrow and see if there is anything under $10. I would need two doser setups so it seems that going the "cheap" route is only worth it to me if I can do the whole thing for under $30 bucks and with some degree of reliability. Otherwise, if I cannot find suitable timers and need the $25 intermatics, I might as well spend a little more and get the accuracy of peristaltic pumps that will dose the right amount in 30 minutes and use cheapy timers.

Thanks for the help so far.
05-14-2007 11:27 PM
Wasserpest You could also go with Wasserpests water pump dosing which doses consistently, and you can play with the concentration of the solution to dose the right ppm's. All you need is a little water pump, they can be had for $10-15, or maybe you have a spare one sitting in your stand anyway.

Let us know if you figure out a way to get this cheap liquidoser to work... it has a lot of potential. One of these days I will start poking holes into airtubing again.
05-14-2007 09:28 PM
dennis I dose Flourish and Fe gluconate at 1ml per gallon per week. Yup, its a lot but the growth is good and I have no fish or inverts issues. So, since it has to happen daily, 60ml total for 7 days is 8.6ml daily for micros. Macros I could mix to get the dose right but I was hoping for a fool proof, easy to use and accurate- oh and really cheap- method of autodosing.

My current test setup in the laundry room seems to give about 47ml per 1/2hour cycle. This may change a little if it is moved to the tank if hose length or head heights change. This also uses 18" of airline tubing in the bottom of my container for the initial dose, which is about 7ml if the tubing is full. I've tried all manner of hole sizes and check valve configurations, all yield similar situations, an eventual venturi that spits. I may try modifying the timer I have so that the actuator is narrower, thereby letting the power be on for a shorter period of time. I am sure I could get it down to only 5-10 minutes of run time this way.

The next option is something like magicmagnani's air doser but I don't like the variation in dose size over time, nor have I been able to control it to dose less than several hundred ml in 1 minute.


Thanks for the tip on cheap timers. I remember seeing some digital ones at Walmart but did not look closely at the time. Now I just need an excuse to go back there.
05-14-2007 07:45 PM
Wasserpest Look for deals on digital timers, Target and WM have them for less than $10, sometimes quite a bit less. I picked up a few that were discontinued models in WM for less than $5, once in a while RiteAid (of all places) has some for free or almost free after rebate.

10cc not enough for you? Wow. My 100gal is (under?)dosed with 4cc daily.

Congrats and have fun on your honeymoon!
This thread has more than 15 replies. Click here to review the whole thread.

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

For the best viewing experience please update your browser to Google Chrome