DIY Dosing Pump Controller Atmega128

[liveforphysics]

Awake from your turkey binge and get cracking on your dosing controller!

I have a pair of tubing pumps, and they've given me nothing but hassle with tubing splitting and leaking every couple months. I hate leaks, or even knowing that something can start leaking in my system. I'm going to use your controller to run aqua-lifters. Super ghetto? You bet, but it's a pump that I've never had leak or fail on me in years of use. They are frequency synch'd and positive displacement. Not perfect, but good enough for an aquarium dosing situation where the ideal amount of dosing is both vague, and always changing from day to day.

 

[BeanAnimal]

My end game will still be to build my own positive displacment piston pumps for dosing. I have a lot of experience with such pumps, but not the tooling required to roll my own minature versions.

I am also somewhat leary of the peristaltic setup, but that is what I will be driving for now.

Cowboys won but I have a headache from a long day...

 

[therealfatman]

Unless you switch to PTFE pump surfaces you are not going to have long pump lives with pumping highly alkaline solutions. That basically means tubing changes or very expensive diaphragm pump heads. I have two PTFE diaphragm pump heads made for masterflex pumps. They sell new for just over $500 each. It took almost a year to find the two used pumps.

I personally gave up on automatic supplementation. I do daily automatic water changes. I adjust my instant ocean salt water when I mix it once per week. I use a single masterflex pump with two matching pump heads with matching tubing sizes. Automatic water changes are by timer and one pump head pumps new water in while one pump head pumps an equal amount of old water out. My ATO is run with a peristaltic pump. My entire culture system for phytoplankton and rotifers is set up with peristaltic pumps.

I probably own and use over 50 peristaltic pumps but I do not use them for calcium, alkalinity or magnesium supplementation. When or if they come out with a tubing that will last through a few thousand hours of pumping highly alkaline water I might try again, but I like the results I get with the automatic daily water changes more than the supplemental system and lesser water changes. My SPS corals have never looked better or grown faster than they do now.

 

[BeanAnimal]

The PharMed and Norprene are both listed as "B" (good) for use with Calcium Carbonate... So even if the 4000 hour pump life (with water) reduces down to 400 hours, that is a year or more worth of dosing at 100ml per day with a #35 tubing pump. When I get the time I will certainly move forward with my plan to build a positive displacement piston pump set. Simple design, a T-BAR and 3 pistons with double ball checks.

 

[therealfatman]

Most pump heads that come up for sell alot are not high-performance pumps but are instead precision pump heads. The largest precision pump tubing #18 pumps at the same rate as the #35 high performance pump head tubing. That is a flow rate of 3.8 to 2300 mL/min. That is a lot of supplement.

I would shoot for pumping a minute or more per dose and pumping several times per day and pick my pump head/tubing size based upon how much I would need to pump each cycle. I would not use large tubing and try to run the pump for only seconds at a time.

Mainly when I refered to problems with high alkaline fluid pumping it was mainly due to short tubing life span with pumping 4 to 5 gallons of kalkwasser every day at a slow rate so long pump hours (4 to 5 hours per day). That and trying to use silicones for carbonates two part solutions. If the tubing will withstand pumping alkaline solutions for 400 hours then; at 7 rpm it would take about 4 minutes per day to pump around 100 ml of solution (27 mL/min). That is over 16 years of tubing life. That should be tolerable tubing length for most people.

 

[BeanAnimal]

That is exactly what my controller is designed to handle.

The #35 head, at 6 RPM is listed at 23 ml/min. My average dose is 150ml/day or about 6.52 minutes.

The controller is capable of dosing in 1 second intervals for accuracy but the dose length and number of pulses is fully configurable.

Dosing Window = number of hours that the system can be dosed. Values are 1, 2, 4, 8, 12, 16, 24

Dosing Start time = The Time of day that the window opens.

Dosing Mode = The number of dosing intervals (pulses) that the full dose is split into. Values are 1, 2, 4, 8, 16, 32, 64, 128

The software is smart enough not to allow doses that are shorter than about 5 seconds to be configured and smart enough not to allow a dose volume setting that will not fit the dosing window.


So for a #35 persistaltic pump at 6 RPM:

Dosing window of 12 Hours
Dosing mode of 4 intervals
Dosing start time at 11:00 PM

I get a total dose time of 391 seconds
or (4) 98 second doses.

If I selected (8) intervals I would get (8) 49 second doses, still well within the resolution of the pump and the controller.

Even 16 or 32 doses would prove to be accurate enough for the pump size and our purposes

Will the tubing last a year or more (from a chemical standpoint) with 2-part solution? I guess that remains to be seen.

 

[therealfatman]

With that short of a running time you can easily use a tubing that is specifically made to handle high alkaline solutions and still get more than adequate life span. Tygon lab or Tygon LFL tubing is usually readily available from many sources and is rated for alkalines with a life span of 1000 hours, therefore over 20 years. Even at high retail such as from Cole Plamer Masterflex it is $3 per foot. That would equate to about $1.50 to $2.00 per foot from Omega or Saint Gobain or from ebay. But it is only retail in 50 foot lengths. Split between a few people though that would not be bad. Even precision tygon lab is rated at 800 hours with alkalines. Considering most tubing is typically cut to a standard 9 inches if furnished with a new pump, that makes for a lot of pieces of tubing.

It is very likely that all the Masterflexpump tubings with the exception of the peroxide and platinum cured silicine tubings would last at least a year if used just a few minutes per day if it is only mechanical wear that is an issue. However, the charts all relate to running time but fail to mention the effects of the solutions on the tubing when the solution is within the tubing but not actively being pumped.

Another advantage of a peristaltivc pump head is that they have a good suction lift. An average of around 20 feet. Therefore you can keep your pump above the storage tank and not worry about several gallons draining if the tubing does wear out. A simple ball check valve as a foot valve would keep your suction lift tube full of fluid between cycles.

 

[BeanAnimal]

I am not sure how many other folks have the #35 heads.

WW-06402-35
Norprene Food
50' $133

WW=06404-35
Norprene A60G
50' $102

WW-06409-35
Tygon Lab
50' $145

WW-06419-35
Tygon Food
50' $140

WW-06429-35
Tygon LFL
50' $140

WW-06508-35
Pharmed BPT
25' $128

The norprene A60G looks to be the best bang for the buck.

800 hours for tygon
4000 hours for norprene
So the big question is, what are the hours with constant exposure to calcium carbonate? Is the norprene still the best bang for the buck for the #35 pump. I don't suppose they will be willing to send me 9" samples of each, but I will ask.

 

[therealfatman]

I imagine Saint Gobain would send a few feet or even a box if you take advantage of your well known user name and talk to a Saint Gobain sells rep. Tell them what you plan on using it for and they will just google your name and their own company name occasionally. As long as anything you say is in the least bit favorable to them you will likely not ever need for products from them to test. Even disfavorable test results will provide them with field tested review to suply to potential customers. Field tests are a lot harder to come by than lab tests and are usually much more widely accepted by customers.

I have had several retailers and several small businesses tell me how many times I have mentioned their business or products on line in reef forums and I was not aware they were watching for such. I just liked their products, prices, and service so recommended them. I still recommend products and businesses that I like.

I am sure Randy has had offers to have equipment sent to him for free just for the testing. I know ever time Randy mentions a particular piece of lab equipment by model number in an article or a forum thread the prices for those particular items increase greatly on ebay. I very much doubt that is Randy's intent when he does so. He obviously just likes the product he owns and uses. But his reputation means his opinions sway the buying audience. I imagine he has the same influence on Reef aquarium chemical testing reagents and such other chemistry related products. This is a site with a huge viewing audience that spends many millions of dollars on reefing supplies.

Randy's articles and work have made a lot of money for a lot of people. How much money do you think are made by different small online retailers off of bulk two part supplements now. How much less would now be made if Randy had not written his two part articles or quit answering questions about their use on in the forums.

I think you would be doing a service to both other reefers for testing the different tubings under normal reef keeping conditions. I do not think there would be anything wrong in using tubing furnished free by the manafacturers. How much would your ethics allow you to skew the results for a few dollars worth of tubing. It is not like they are giving you a huge research grant to do research and you are not bound by a professional society code of ethics to not except such items for testing. I really can not see a possible breach in professional ethics to give a hobby aquarist tubing to test. After all your profession is electrician not a chemist. Especially if they were just sending a few feet of many different tubing types.

With almost 15,000 posts on RC I believe your name and reputation is pretty well known.

I very much doubt the more genearl retailers (like Cole Plamer and Omega) would send anything though. I would try Saint Gobain, Professional Plastics, US Plastic, or Industrial Plastic tubing. saint Gobain is --the-- major manafacturer and the others are the major distributers. Saint Gobain sells 500 to 1000 foot rolls for about what Cole Palmer sells about 100 feet to 200 feet of Masterflex tubing.

I have a lot of the different sizes and types of L/S tubing but the only I/P tubing I have is number 26 which is half the pumping capacity of number 73.

 

[bwilcox]

Quick question? Will your medication be higher or lower than the pump when your finished? How will you store the solutions to be pumped?

Thanks

 

[BeanAnimal]

The solutions will likely be lower than the pump so that split tubing does not allow the containers to drain. I have not picked out new containers yet but I am currently using 2.5 gallon polyethylene carboys.

 

[Bryan]

Any updates?