# Automatic Continuous Water-Change, Dosing and Water Analysis System



## KhuliLoachFan (Mar 8, 2008)

I am musing over an idea for an automatic water changing, dosing, and colorimetric water analysis system. This would be a colorimetric analyzer that uses the cheap manual color-based chemistry water test systems, and a peristaltic pump, and a low-cost laptop (like an ASUS EEE PC) and some custom hardware controls and software (designed by me). It would be useful not only for slow water changes, but also for gradually shifting a brackish water tank's salinity upwards, and being able to monitor the tank water opacity and color. I should be able to detect color cast in the tank water much more accurately using a camera/sensor, and keep a tank history. This could be useful for a tonne of different things. Need to check every two hours for some kind of tank chemistry crash? Just drop in an inkjet-cartridge type thing full of some $8 solution, and off you go. You come back 24 hours later and you've got 24 one hour samples already analyzed. You can keep it going for weeks or months without any maintenance. 

Has anyone else ever considered something like this? Does something like this already exist? I'm a professional software geek, with a tonne of control systems and analytical chemistry experience, so I think I could pull about 50% of this off myself, and I would need a little help with the metal-work and enclosure. I'm thinking this would sit on feet, above your tank hood or lighting, and on top of that, a little EEE PC.

I've done the napkin sketch, and I know I have a workable design. Valve and peristaltic pump motor control will be done via a low cost PLC. Total parts cost is going to be about $1000 for the prototype. I would think a commercial system like this I could probably sell for anywhere between 10K and 20K. 

I'm talking crazy talk, right? 

W


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## twoheadedfish (May 10, 2008)

you're talking gibberish to me, but the idea sounds amazing. i hope you can pull it off / maybe sell the contraption/plans?

i'm really curious as to how this is going to turn out.


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## ameekplec. (May 1, 2008)

Automatic water changes and such sound dandy to me. I don't know what other systems run off of, but I'd imagine theirs are also automatic or somewhat continuous.
What would you have the drop checker for? They have pH units that generally are around 250 new that use a pH meter, which is more sensitive than colorimetric sensors which are going to be much less accurate unless you can somehow make the whole sensor enclosed so that you can get a better reading. You could link these to the computer to control wc's I suppose.
Would you develop a sensor/drop checker for some other parameter (ie nitrate, ammonia, etc etc)? I'd have to imagine that some of the other parameters would be somewhat difficult to monitor real time (there are ways, but I'm sure for these applications they are either impractical or too costly). The only other one I can think of that would be a decent way to monitor water quality might to be monitor the conductivity (TDS) of the water and base the water changing on that. You could probably get a decent meter for not too much too.

With your expertise you can probably pull it off. I'm sure this is definitely a system that you could market or at least sell the idea/prototypes for and make a pretty profit. Can't wait to see what you come with!


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## KhuliLoachFan (Mar 8, 2008)

The colorimetric sensors would be reading the cheap chemisty-test-kit reagents. This would be cheaper in use than having one sensor for PH, a different sensor for Nitrite, and another for Nitrate, and another for Ammonia. 
My current napkin design has four "inkjet cartridge" injectors that would use an inkjet like piezo electric pumping system to do its own internal test-tube stuff, as well as additions (the outflow from the reactor/testtube can be directed to a waste bin, or back into the tank, which would be useful for medications.

The color sensing would be quite accurate because I have thought of a low cost self calibrating highly accurate color reading system that I think is quite ingeneous. The chamber would be completely enclosed (dark) and internally lit. 

W


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## ameekplec. (May 1, 2008)

Ah, I had though that you were testing inside the tank. The self-testing 'box' would be quite ingenious and would certainly be something to see. I'm guessing something like an automated dispenser and some servos to agitate tubes. The drop dispensing part would be something to see too. All something that can be done, but it will be interesting to see it done on the hobby-level.

I suppose the only thing you would have to do really is refill test solutions and empty the waste container.

good luck with this DIY!


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## KhuliLoachFan (Mar 8, 2008)

The proof of concept will be just the photo/colorimetric analysis software. If I can make that work (100% software and off the shelf imaging components) then I'll build the various pump, valve, and metering components. 

W


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## Shattered (Feb 13, 2008)

All I have to say is "You Crazy" (meant in a very good way). If it works you'll be taking DIY to a whole new level. 



I wish I could help, but it's all way out of my league. All I know is woodworking and custom computer hardware.


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## Cory (May 2, 2008)

Continuous drip systems already exist, as do all forms of automated water changers and dosing equipment. Sounds like the difference with yours would be the laptop monitoring which is really scientific and cool sounding (although maybe commercial sites also already have this). A bit more than a hobbyist requires certainly, but I take it that being a techy person it's more of a fun project than something you feel you need. I'd be very interested to see how it all turns out although unfortunately, I cannot offer any advice on the setup or help with the metalwork either lol. 

What sort of setup will you be using this with or is the idea just to try and sell it for commercial use? I don't mean to be a killjoy but if your plan is to sell this you will have a lot of stiff competition already in place. Similar, if not identical systems are already available and in use at places like Wal*Mart and many commercial fisheries and the units wal*mart has have 30 tanks included and sell for 3 - 4k. 

Whatever the case, best of luck and keep us updated!


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## KhuliLoachFan (Mar 8, 2008)

*funs!*

For starters, it's just a DIY techno-toy.  It's not a business idea, just for fun.

Right now I'm playing with the concept and doing research. If anybody runs across a unit that does all this, for any price, please send me links so I can read up.

W


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## Chris S (Dec 19, 2007)

http://www.automatedaquariums.com/

Interesting article: http://ww.pennnet.com/display_artic...or-spot-DO,-pH-measurements-courtesy-of-Hach/

I'm sure many things exist, especially in the ecotoxicological area of research. I imagine most LARGE aquariums (Seaworld for example) use something (check out the article above).

To make an affordable, household use version would make you some money. Aside from that...I dunno!


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## ameekplec. (May 1, 2008)

I agree with Chris...realistically, a unit for around 600 - 1000 bucks would be in the hobby range still and be affordable enough that people could actually buy it, but still expensive enough that it's a definite luxury item to be drooled over.

And, yes, systems like this do exist for research grade applications, but are very expensive, and usually in place in large scale systems.

good luck, and if it's around 500 bucks, sign me up


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## KhuliLoachFan (Mar 8, 2008)

*aquatronica*

The BigAls in scarborough has the Aquatronica controller system on one of their reef SW tanks. They look SUPER COOL. But not what I want.

I have been unable to find a continuous colorimetric system for the hobby market as of yet. The boiler/industrial world has colorimeters for various industrial users. It must work, or they wouldn't do that. 

W


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