My DIY Drop Checker

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loaches r cool

Snail Terminator
Original poster
Feb 15, 2006
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Gahanna, Ohio
tristan.homelinux.net
Well, I decided to see what I could make for free (or there abouts) with stuff around the house. The main two parts of this design are a funnel and a very small baby food jar. From there all you need is a method of placement in the tank, I used a leftover bracket from a powerhead that goes over the tank rim and is adjustable, then just took a scrap piece of clear plastic to connect the two (I used polycarbonate since I have a ton of scraps, but of course acrylic would be the common choice).

Here are some pics (click them for bigger ones):

Baby food jar (free as a side effect from feeding a baby :)), and a funnel that came in a 3 piece set for $1.99 from the local super store. I cut the hole with a step drill bit but my bit wasnt quite big enough so I used a dremel to enlarge it to the right size. The funnel I cut with a band saw.


The finished product with a bracket from an old powerhead and a strip of plastic. Everything attached with aquarium grade silicone.


The funnel could have been trimmed more flush but I chose to leave the funnel extend a bit lower thinking that it would give me a little extra air/water surface contact area.


This shows just about everything used, except for the tube of silicone, baking soda, and the cutting tools. I made a batch of 4* test solution with a gallon jug of distilled water. I put the rest of the solution in another normal size glass jar, I hope it will keep some time because its a PITA to make. I use a graduated syringe and put 20ml of solution in the drop checker. Probably would look a little better with some more fluid, maybe like half full. That would probably be ~30ml or so I would guess.


In the tank. I just stuck it in the corner, its such a forest in there you cant really see it from the front. I'll soon be moving it to a sump anyhow.


And now green, the next morning. I wanted to time how long it took to change, but I didnt get it in the tank till late the previous night and in under two hours when the lights went off it hadnt really changed much from blue yet. This is how it looked the next morning after lights on.


The white color of the funnel helps a bit in seeing the color of the fluid it little more clearly.

Overall I'd have to rate this project very easy, just make sure the silicone seals completely around the funnel to the jar end.

I'm not entirely sure what kind of finish the baby food jar metal top is, I suppose thats the only questionable part of this. I'll keep my eye on it and if it starts to oxidize or corrode then I'll pull it.
 

loaches r cool

Snail Terminator
Original poster
Feb 15, 2006
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Gahanna, Ohio
tristan.homelinux.net
Not really sure, it wasnt very much but I did it here and there. Maybe 10-15 minutes to cut the funnel and cut the hole in the lid, then a few minutes to silicone the funnel into the lid, and the jar onto the plastic support. Then after a day I siliconed the support onto the bracket. After letting all the silicone cure for the better part of the next week I made the test solution and put it in. The test solution probably took 20 minutes or so to get the KH set and was by far the most tedious part of the whole thing (but still no big deal really).

FWIW I think drop checkers are still only ballpark to get close to a desired co2 level, but probably the best method other than letting a pH controller do it all for you).
 

legendaryfrog

Tactical Refreshment Action
Nov 25, 2006
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arlington heights - hoffman estates, IL
It looks cool... I have to admit some ignorance though.... what is it testing, and how?
yeah....I'd like to know that aswell. Im thinking it has something to do with co2, but I dont see it hooked up to anything.
 

Mgamer20o0

BobsTropicalPlants.com
Staff member
Jun 4, 2003
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short answer is the funnel traps the co2 gas rising in the water. there is a air bubble in there along with the trapped liquid. as the co2 builds up it reacts with chemicals. the change of color indicates co2 levels.

loaches r cool there are places online to get them for $10. now that you did it do you think it would have been better to buy or make it? i been thinking about buying a couple for my tanks. i am unsure right now if i would rather try to make one or just buy one.
 

necigrad

AC Members
Feb 7, 2007
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Las Vegas, NV
It looks like it's only a few bucks, but he also had some stuff lying around. I'm going to guess that it's probably worth it to just pop for the premade ones, especially if you need to make several.
 

loaches r cool

Snail Terminator
Original poster
Feb 15, 2006
1,830
0
0
Gahanna, Ohio
tristan.homelinux.net
It looks cool... I have to admit some ignorance though.... what is it testing, and how?
Sorry! Yeah it measures CO2 for planted tanks. Basically blue = to little co2, green is just right. Its basically using the pH/KH/CO2 relation except with a solution of distilled water at a set KH. A KH of 4* in the drop checker will turn green around 30ppm.

Mgamer-Yeah I actually have one I bought. If I remember right it was made by Red Sea but it doesnt look like the ones they have now, and when I originally bought it it was closer to $20. It works ok, my diy one has a couple advantages though. The ADA glass ones are nice lookin, ebay has some knockoffs. On other forums many have built DIY crop checkers and atleast one guy actually sells his diy ones. So it was just an idea I had for a while, no biggie really.
 
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