DIY dosing pump
Printed From: Utah Reefs
Category: Specialized Discussion
Forum Name: DIY
Forum Description: Do it Yourself
URL: http://www.utahreefs.com/forum/forum_posts.asp?TID=14902
Printed Date: December 20 2025 at 8:33am
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Topic: DIY dosing pump
Posted By: Kevin
Subject: DIY dosing pump
Date Posted: October 31 2006 at 10:34am
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Just thought I would share some info and see if I could get some help.
Inspired by something I saw yesterday I tried making a homemade dosing pump, and it turned out to be fairly simple. Basically you need an air pump, some sort of air-gang valve, a 2 liter bottle, and some airline tubing. You hook the air pump to some tubing, the tubing to the gang valve, then more tubing is connected to the other side of the gang valve and connected to the lid of the bottle with an air tight seal (so it is pushing air into the top of the bottle. Then you take another piece of airline tubing and put it in the bottom of the bottle, through the lid (air tight seal), and up to the tank that you are dosing stuff into. Basically you use the air pressure from the air pump to push some sort of fluid up the line and into the tank. You use the gang valve to control how much fluid is being dosed. One component I think would be needed is a inline one way valve that would keep the fluid from flowing back into the bottle if the pump were to turn off. It seems like this would be a great way to drip kalk, or maybe add phytoplankton to a tank if you don't want to add it all at once. What I was hoping to do with it though was to use it for dosing my balanced addatives. Is it possible to dose an accurate amount with an air pump? Also is there any way to get more fine tuned control with a gang valve? Last but not least, anyone know where to get cheap inline one way valves? |
Replies:
Posted By: Adam Blundell
Date Posted: October 31 2006 at 10:59am
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Kevin-
I think you can get the one way valves at petco. But they may only work for air and not liquid, I don't know.
I would think the rate of dripping would change as the volume of air/liquid in the bottle changes. Not sure. But then again how accurate would it have to be. I just dump a little buffer or a little calcium in my tank ever few days. This would certainly be a more consistent type of addition for someone like me.
Adam ------------- Come to a meeting, they�re fun! |
Posted By: jfinch
Date Posted: October 31 2006 at 3:53pm
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couple thoughts...
I'm not sure the airline valve does anything. A valve only works when there is flow going though it but you're not going to really have any flow. You'll really just pressuring up the dosing vessel (pop bottle). You will have some flow as air displaces the liquid in the bottle, but it should be displacing very very slowly. I'll bet that if you were to put a pressure gauge on the bottle you'd find that the pressure was the same regardless of valve position (other then completely closed). Can you actually regulate the dose rate by adjusting the air valve?
Also as Adam points out, the dose rate will decline as the liquid level in the bottle decreases because the liquid needs to be pushed to higher level.
And the air pump is basicly being operated in a blocked-in condition. I don't know if they are designed to operated that way. It might get hotter (and shorter life) then it otherwise would. ------------- Jon https://www.youtube.com/channel/UC6y_EzjI_ljbIwf2n5uNzTw" rel="nofollow - What I've been doing... |
Posted By: Kevin
Date Posted: November 06 2006 at 2:26pm
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Just thought I would give an update.
1. The air pump idea was a total bust for a dosing pump. It was way too hard to control flow. I still think it would work well to dose kalc or phyto though. 2. I have a new idea though for dosing pump that I have been experimenting with. So far it is actually working VERY well. I am not sure how accurate it is though (Meaning if I am dosing 100 ml over 2 hours do I get 100ml or am I getting 95 ml, or maybe 105 ml (and is it that big of deal). Total cost for it would cost between 10-20 a piece. I don't have time at work to give details on it, and I would like to test accuracy a little longer but I seem to have a solution to the expensive dosing pump problem. |
Posted By: Kevin
Date Posted: November 13 2006 at 2:41pm
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Ok, so I am tired of trying to test this thing so I just thought I would post it and see what everyone thought.
Here is a picture of what it is and how it works. 
So basically you have a small motor that goes fairly slowly. On the little gear piece I made an acryic piece that fit and drilled holes in that piece for various dosing rates. Then I took a piece of steel rod (any rod will work) and bent it to stick in the hole, and bent the other end and hot glued it to the syringes plunger. The syringe I fixed in place and on the end of the syringe I put a plastic T. One the other ends of the T's I put one way valves that flow the same way. So here is the operation steps. 1. basically the motor rotates pulling the plunger out, witch creates a vacuum and pulls liquid up the line and into the syringe. 2. the motor continues to rotate pushing the plunger in. The fluid cannot go back down the line because of the one way valve so it continues up the line. 3. The process repeats and basically the fluid can never return down the line because of the one way valves. I have done some testing with my 3 rpm motor and it produces very consistent results when operating at the same height from source to syringe to output. Every 2 minutes on mine (trying to get syringe to use its full length) it would push about 4.1 ml of fluid. (If if was pushing the amount I thought it should it should have pushed 6 ml). The things I don't know is how it will work over time. Namely, how long before the syringe wears out. How long before the one way valves stop working right. Here is cost of supplies. 1. (1) 3 rpm motor -- $3.99 https://www.surpluscenter.com/item.asp?UID=2006031613352805&item=5-1563-A&catname=electric - 3 rpm motor (I know it says 2.5 rpm but that is what I bought and it is 3 rpm.) 2. (1) 1mm syringe -- $0.25 at calranch (or try a pharmacy) 3. (2) One Way Valves -- $2.00 -- http://www.petsmart.com/global/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524441811424&FOLDER%3C%3Efolder_id=2534374302030092&ASSORTMENT%3C%3East_id=2534374302023693&bmUID=1163450159759&itemNo=5&Ntt=valve&In=All&previousText=valve&N=2 - One way valve 4. (1) Plastic T -- $0.99 from Home Depot for a pack of 5 5. Tubing -- I used rigid tubing hoping maybe it would make flow more consistant. I don't know if that makes a difference. Also, you will need to figure out how to connect the tubing to the syringe, it is a loose fit with the tubing. I ended up using a larger piece of tubing on top of the syringe and other tubing to make a nice fit. So in all the dosing pump would cost 7.25 not including the price of shipping and not including the price of a timer. I liked the idea of an electronic timer that would allow you to turn it off to within a minute but you could try and get it to dosing the amount you want on 15 or 30 minute intervals. So let me know what you think. |
Posted By: jfinch
Date Posted: November 13 2006 at 6:44pm
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I like this idea better then the air pump. What you show is the basic way every industrial sized positive displacement pump/compressor works. And you've identified the weak points (inlet/outlet valves and piston rings).
Too many moving parts that'll breakdown, imo. Why don't you just buy a peristaltic pump head on ebay (I bought mine for about $20 shipped, such as this one: http://cgi.ebay.com/Masterflex-Easy-Load-Peristaltic-Pump-Head-1-NR_W0QQitemZ200046349535QQihZ010QQcategoryZ26237QQrdZ1QQcmdZViewItem - http://cgi.ebay.com/Masterflex-Easy-Load-Peristaltic-Pump-Head-1-NR_W0QQitemZ200046349535QQihZ010QQcategoryZ26237QQrdZ1QQcmdZViewItem ) and fit to the 3 rpm motor you have and put a timer on that? ------------- Jon https://www.youtube.com/channel/UC6y_EzjI_ljbIwf2n5uNzTw" rel="nofollow - What I've been doing... |
Posted By: Mark Peterson
Date Posted: November 14 2006 at 12:19am
Reinventing the wheel is just so much fun.
But I agree with Jon. We have drilled there already and we found that it was a dry hole.
 I use my peristaltic pump for dosing Kalkwassser at night. It's almost 100% of my topoff water. The pump is plugged into the same timer that turns on the RDP light. ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member 
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Posted By: Kevin
Date Posted: November 14 2006 at 10:05am
Why is it I can search for stuff for two weeks and in one day Jon can always show me where to find it in one day  .
I don't know if I am ready to give up just yet. But thanks for the info. |
Posted By: dnellans
Date Posted: November 14 2006 at 10:30am
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mark, how quickly does your tubing become too stiff/brittle dosing kalk via this method? i've thought about dosing kalk as you are but figured that without some sort of chem resistant tubing the tube might become brittle and need replacing quickly, on the order of weeks at most... -dwn ------------- http://david.nellans.org |
Posted By: Mark Peterson
Date Posted: November 15 2006 at 3:30am
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It's been going for >2 years. I use silicone tubing for the dosing pump. Lately, I could hear a change during operation, like it was getting stiff. Replaced the rest of the tubing in the process, a combination of vinyl and John Guest tubing, both showing signs of terminal brittleness. ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member
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Posted By: Kevin
Date Posted: May 02 2007 at 2:01pm
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Thought I would give an update on this -- It half worked, and half didn't work.
The calcium portion worked just fine and I am sure if I still had it up and running it would continue to work. Unfortunatly the alk side did not stand the test of time. The problem is that the wants to precipitate out of solution onto everything. Well it did this inside of the one way valve and prevented it from doing its job, so the solution was sucked into the syringe, and then pushed back from where it came from instead of going up the tube. I recently saw another post about using an air pump as a doser and I may play with that some more before I give in and do the peristaltic pump. |
Posted By: Mike Savage
Date Posted: May 02 2007 at 5:57pm
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Kevin, too bad it didn't work but thanks for the update.
Mike -------------  |
Posted By: gateb
Date Posted: May 02 2007 at 9:48pm
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I messed around with several pumps and check valve schemes to pump water from my reservoir though my kalk reactor to the sump. It's switched on and off by a solenoid operated auto top off device. It's working fine now, but It would have been cheaper and I would have had a lot fewer mishaps if would have just bought a peristaltic pump in the first place. My kalk reactor is 3 ft tall and the main problems I had were: 1. The checkvalves not preventing backflow resulting in the contents of the reactor draining back int the sump. I tried the airline ones and a brass swing type from Home Depot. Then I did some research and found out the RO/DI water corrodes brass so I ended up with a 3/4 inch PVC checkvalve from Home Depot with adapters to fit it to my tubing. It has still backflowed a couple of times until I ran the feed line all the way up to the ceiling. Arr! I really need to just order the peristaltic pump and be done with it.
2. Water continuing to flow into the sump after the pump shut off resulting in the entire reservoir siphoning into the tank. I won't go into the reasons here as I've probably babbled enough already.
Anyway, if you want to save yourself lots of headaches and aggravation, just get the peristaltic pump and be done with it. ------------- 120 Gal RR 2 Pan World 100PX return pumps AquaC EV-180 w\Mag 9 40 + 13 Gal refugia 2 175w Iwasaki Aqua2 MH 4 48" URI Super Actinic VHO IceCap MH and VHO Ballasts Ogden, UT |
