The suction cup holds well, the Orb is easy to position, and most importantly, in my opinion it fits perfectly in my 30 l Nano Cube. The round shape makes it look good, and since it's relatively small, it doesn't look too intrusive either.

Refilling the checker fluid is absolutely easy! No dripping out! The suction cup holds well on the glass and the checker can be positioned nicely!

I think the Pico size is perfect for my nano aquarium and it looks good too! Very satisfied.

I like the minimalist design. Simply attached to the side glass. Excellent

I ordered it for my 25 liter shrimp tank and I have to say, it simply looks excellent. The drop checker is barely noticeable but still looks very stylish and high-quality. The color is also easy to read if you look at it from the right side, as seen in the picture.
For the price, a really nice piece that serves its purpose very well. A clear recommendation.

I prefer using the Orb Checker because it is much more compact than the classic drop checkers. Cleaning is a bit more difficult, but I'm happy to accept that, given that it's only a third of the size.

I bought this drop checker for a 45 P tank. The size is really perfect. At 2 cm, it's tiny compared to other drop checkers. Filling and emptying it works very well with a pipette. Highly recommend!!

For me the most beautiful one of all. I use it for my LIDO 200. It's very sturdy and has now been in use for 1 year without any problems.

The Orb Checker is well made and looks very good in small to medium-sized aquariums. You really don't have to hide it! The only thing is that the suction cup (like all transparent suction cups so far) turns milky white after a very short time. Fine with frosted-glass background film, bad with dark backgrounds. A black suction cup as an alternative option would be great!

So if you want a discreet checker, you can't go wrong with this one. Unfortunately, emptying and filling it is a bit tricky at first.

We now have this CO2 checker installed in all our tanks. Personally, I like the Nano version best. The suction cup has held up perfectly so far.

The Orb Checker is made of glass and is of absolutely top quality. I'm very satisfied with it. The color is super easy to read. Use a syringe to help with filling, then the whole thing is super easy.

Easy to fill with indicator fluid and attach in the tank. Shows the current CO2 saturation of the tank water quickly and without any fuss. Would buy again.

The Orb is very well made and doesn't give the impression that it will break any moment ;-)
Easy to fill, and thanks to its small size it's hardly noticeable in the tank.

I have both the Nano in a 110 l tank and the Normal in a 240 l tank.
First of all, they simply look good. Yes, the transparent suction cup turns cloudy, but unlike other suction cups it still holds very well.
I ordered 250 ml of CO₂ check fluid right along with it, ok, that was maybe a bit much. Surprisingly, I only replace the fluid every 4 weeks (even if just to be on the safe side). A plastic pipette for filling and emptying again is included.
So, 5 stars. It's going into my next tank, too.

I am very happy and very satisfied with the Glass Orb for CO2 tests. The design is very nice, it is very easy to fill it with the right dose of liquid for the CO2 test (I add 2 ml to the larger Orb model), and most importantly, finally a glass container for the CO2 test in which you can clearly see the color of the liquid !!!. I have always used Dennerle CO2 systems; previously I used the rather ugly balloon-shaped plastic container that came with the Dennerle CO2 kits; in this rather large plastic container it was relatively easy to see the color of the liquid. The newest models of the Dennerle Carbo Power CO2 systems come with a glass container for CO2 measurement. The glass is somewhat darkened, and with a colored suction cup...black! (Please give him a pirouette as a prize for the prodigious designer of this container ...). It was absolutely impossible to tell what color the CO2 test fluid was unless your eyes were equipped with super X-ray vision or the like ... an amazing fiasco. But with this Orb and the 20 mg CO2 test fluid from Aqua Rebell, you can clearly see the green color of the liquid in the Orb less than 2 hours after installation (if the amount of CO2 dissolved in the aquarium is right, of course). ). I installed it in a small tropical aquarium of 126 liters, with dark water from lots of tannins and humic substances, with floating plants (Limnobium laevigatum), and still the visibility of the CO2 test fluid is absolutely perfect. I would buy it a thousand times over without hesitation, it is absolutely recommended, both for the design, the Orb is very beautiful, the ease of use and the clarity of reading. Together with the 20 ml Aqua Rebell Check test fluid it is simply perfect

I'm a big fan of these little Orb Checkers and this one from Aqua Rebell serves its purpose very well!

already have 3 Orb Checkers by now ... it's simply inconspicuous & I'm more of a fan of little or no visible equipment in the tank ...
however, the transparent suction cup turns whitish after just a few days ... that's the drawback, and that's why only 4 stars ...

Have had the Orb Checker in the tank for 2 years now. It looks like new and, most importantly, the suction cup still holds rock solid to this day

I really like the look of it. Cleaning and filling are a bit awkward. But it's just a matter of practice. Has something about it somehow. OK

Just right for my ADA 45p. Small and unobtrusive. Fits perfectly. Very good build quality, and at an affordable price. Addendum: It's a bit fiddly to swap out the contents.

A very discreet little drop checker. I went with the Pico edition. Looks good, filling it is a bit tricky but it works. Satisfied,

Delivery was excellent as always!

I love this design, the glass looks high-quality. For the price you can't complain, but I would have preferred a transparent suction cup.

As you can already tell from the headline, I'm thrilled!
Compared to all the other drop checkers I own, this one is the smallest and most discreet (which is certainly not a disadvantage when aquascaping) and it is very reliable and easy to handle!

Only this one from now on!

It's easy to fill, looks good, and is really easy to read. I would buy it again anytime. And not too expensive.

I bought the Orb Checker in the Nano version and use it in my 30 l Nano Cube measuring 30x30x35.
The Orb Checker fits perfectly in my tank and doesn't look bulky at all. It's a perfect alternative to the bell-design drop checker, as it's much smaller and still works, which is really a given.
I find it a bit harder to fill than the bell-design drop checker, so I recommend using a pipette for filling. That was the only negative point I noticed in use.
In summary, the Aqua Rebell Orb Checker is a very, very good product that I would definitely recommend.

I ordered the large version and it really looks impressive. I personally prefer it to the curved tubes. Curious to see how it performs (filled with Aqua Rebell CO2 Check 30mg/L)

The Nano Orb does what it's supposed to do and looks good. Would buy it again. Not very noticeable in the 60 l cube.

Always happy to use it, and I have this product in all my aquariums because it just looks fantastic! The only drawback is cleaning the inside.

Blends well into the tank, installation was simple.
Let's see how it holds up over time, maybe an update will follow

We now have the Aqua Rebell Orb Checker in use in two tanks. The Normal size in the 375 l tank, the Pico in the 60 l tank.
It's well made and does what it's supposed to do. Unlike its predecessor, the suction cup holds well too. It should be clear to everyone that it doesn't stay as nicely transparent as when it was new.
Something to keep in mind is that you do need a neutral background. For us that's no problem in either tank thanks to the light background. If the tank is completely green, it could become problematic. Checkers that have a white surface built in are surely better suited for that.
Compared to the Pico, the size of the suction cup looks more harmonious on the Normal. But I'd rather have a slightly larger suction cup than test fluid in a small tank.
And the price is fair, too.

Very discreet and just beautiful. Filling is easy, too. Perfect for my 60P.
Super fast delivery from Aquasabi.

Just as good as any other vessel for a drop checker for the CO2 level in the water. I chose this one because I find it a bit more discreet. In the end, you should simply pick the one you like best. But I can absolutely recommend buying it.

By now, for me the most beautiful checker, the Pico especially is very unobtrusive but has a lovely design. Shipping was damn fast, as always

I use this CO2 checker in my MiniM as well as in several cubes. Nice, simple and compact look. For me, it's the only one.

A really nice and stylish CO2 drop checker.... And that's all there is to it.
Unfortunately it's hardly possible to read the test fluid accurately, since the checker is completely transparent. A white backing would be a big advantage. The product photo is very misleading in that respect, as it was photographed against a white background.

This little drop checker is absolutely well made and very sturdy, it has already survived a few falls. What I like best is that it's so nicely small and unobtrusive. Perfect for nano aquariums.

I ordered the Normal size. It's handy and could also be filled using a syringe with a short piece of thin tubing attached.
With a dark back wall the contrast is very low, but the yellow color is still the easiest to make out. A few plant bits drifted into the Orb, but the contact surface is easy to get to and easy to keep clear. My otherwise very curious fish ignored the Orb - probably precisely because it's completely transparent.

A very attractive CO2 drop checker! You can integrate it into a layout really well and it isn't visually too intrusive. The Orb Checker is superbly made and is easy to fill with the indicator fluid!

As always, very fast delivery. In my 30 C it's very unobtrusive and still easy to read. The suction cup turns white over time, like all clear rubber parts.
I would recommend the product anytime.

Nicely small and really unobtrusive. I can see the color well and the thing does what it's supposed to do. Really highly recommend.

I like the look of this Orb Checker much better than the drop checkers. I have the Nano version in an 80 l tank and the size is perfect.

An eye-catcher in any aquarium, absolutely high-quality in appearance and workmanship. Great product. Easy to fill, suction cup holds perfectly. Highly recommend!!

Beautiful look and properly made. I have the checker in three of my tanks right away because its look appealed to me so much.

the price and performance are right, easy to use and the thing does what it's supposed to do, there's not much more to say about it.

Super nice design, holds well on the glass, fills easily, I immediately ordered a really small one for my future small tank, absolutely excellent and cleanly made

Very unobtrusive but nicely shaped! I immediately ordered another one for my future other tank! Clean workmanship and classy in the tank

The Aquasabi Orb Checker looks great and serves its purpose.
I highly recommend the Orb Checker!
For my 200 l tank it's perfect!

Easy to handle and unobtrusive, I like the shape, so I can recommend it. What else should I write, everything has been said

Very nice design, I like it a lot, would buy it again
reliable indicator, checked with a pH meter. So that's my review H.J.E.

I have it hanging in my 30 l nano..
Great design and unobtrusive.. I put the Dennerle single-portion pack in it and that lasts very well.. Suction cup strong..

I deliberately bought the Pico version of this drop checker for my 20 l tank and am very satisfied.
It blends in wonderfully in small and medium-sized tanks, sticks rock solid, is easy to fill and, in my opinion, is above all visually the best option compared to the otherwise rather bulky-looking drop checkers. Excellent.

I have this one in my smallest tank. I love these things because they're unobtrusive and pretty. They hold great on the glass and reliably show whether the CO2 level is right.
Also simply nicer than the plastic ones.

I got one of these for my 60 liter cube. Wonderfully unobtrusive and easy to read. I would buy it again anytime.

Until now I had the Dennerle egg, but I didn't like its look. I'm completely satisfied with the Aquasabi Orb Checker and highly recommend it. The indicator fluid is also easy to read, i.e. the colors are easy to make out.

The Pico Orb checker looks really cute. It fits perfectly in a small nano tank, though. It's just that the suction cup is even bigger than the checker, maybe I can think of something better.

Perfect for a 40 l aquarium tank, small and unobtrusive :)) I'm thrilled! Looks great and the measurement is accurate and reliable.

A bit hard to read in less than optimal light! Otherwise superbly made and does exactly what it's supposed to do! Visually, of course, a real eye-catcher

I consider this Orb the best solution among CO2 checkers. Well made and not too conspicuous in the tank. Maybe the suction cup could be gray, like the ADA Grey Parts.

The Orb Checker Pico is really small and hardly stands out in the nano.
Filling it with a syringe is no problem.
I'm very satisfied.

... that's how the Orb Checker goes into the 60 liter tank. The Orb Checker has a nice size, it holds, the glass is transparent. Very satisfied.

Very good looking CO2 checker, doing what sopposed to do. Nothing else to add to this subject. Have a good day.

I had the Dennerle Profi-Line CO2 long-term test set, but the plastic checker didn't appeal to me at all visually... Here I got the smallest version of the Orb Checker for my 30 L Nano Cube and now run it with the small Dennerle CO2 Special Indicator tests. Works perfectly and looks great!

I have the Orb Checker in the sizes Pico and Nano. Totally satisfied. Small, functional and unobtrusive.
And, as always, fast delivery from Aquasabi within 24 hours.

Highly recommend!

It costs only 10 euros and looks better in the aquarium than my other one that cost almost 50. Shipping excellent, everything great with this retailer.

I had been looking for a long time for a permanent CO2 tester that doesn't dominate a nano aquarium so much and also looks good. I found the usual versions either ugly (Dennerle, JBL) or they stick out far (Orinoco).
This little "Orb Checker" (pico) blends in perfectly with the look.
The workmanship is perfect and the transparent suction cup is hardly noticeable, and it also holds firmly.
It can be filled with the Dennerle refill set, for example: with the single-use plastic capsule the "checker" is easy to fill; you should leave out 2-3 drops, otherwise it overflows.
The only drawback, if you want to see it that way: there is no white background built in. That would make it a little easier to read.

The Orb Checker works great and fits well in my tank.
Of course the shape is a matter of taste, but if you want an unobtrusive drop checker that, in my opinion, is also nice to look at and does what it's supposed to do, I can recommend the Orb Checker without reservation.

Very discreet and stylish. Easy to read when the water is clear, a bit harder when the water is slightly tinted by peat. Filling works without any problem with the included plastic pipette.

Compared to the usual plastic solutions (with seals etc.) from other manufacturers, probably indestructible, very stylish, and not more expensive either. Thumbs up.

You can't "measure" the CO² level any more easily. As long as the test fluid is green, everything is okay. The suction cup is soft enough that you can also attach it to slightly curved glass.

Perfect drop checker for my Nano aquarium. Small and discreet and easy to Install. Just the thing to monitor CO2 levels in a Small tank.

Ordered the CO2 drop checker 1x in Pico (for 54 L) and 1x in Normal (for 250 L). The Pico is very small, but still easy to read.
What I think is great is that it fills easily. I did it with a syringe (BRAUN 5 ml) and a veterinary cannula! Works great!
The test fluid can also be drawn off again easily that way. Before first use I rinsed the checker with the test fluid (filled it + drew it off again and then filled it)!
The suction cup also holds great, but it could be a lot smaller on the Pico.

I'm glad I bought this drop checker (I previously had the ISTA Angled Eye). The rubber ring (seal) on that one breaks quickly.

Ordered the CO2 drop checker 1x in Pico (for 54 L) and 1x in Normal (for 250 L). The Pico is very small, but still easy to read.
What I think is great is that it fills easily. I did it with a syringe (BRAUN 5 ml) and a veterinary cannula! Works great!
The test fluid can also be drawn off again easily that way. Before first use I rinsed the checker with the test fluid (filled it + drew it off again and then filled it)!
The suction cup also holds great, but it could be a lot smaller on the Pico.

I'm glad I bought this drop checker (I previously had the ISTA Angled Eye). The rubber ring (seal) on that one breaks quickly.

The drop checker looks good, is nicely small and, with the transparent suction cup, relatively unobtrusive. Highly recommend. For just under 10 euros, a great alternative to the high-priced products from ADA and co.

Delivered fast!
Accurate CO2 drop checker. Nice design and easy to integrate into the aquarium. At a glance you can see whether the CO2 level is good or bad.

The glass part itself is great. Superbly made and, in my opinion, so-so to read. Of course a unit with a white background is easier to read, but being so nicely small and clear it suits my tank! I haven't found a nicer and smaller drop checker.

Points off for the suction cup, which in my opinion is too big, it ruins the Pico look again. I considered sending the thing back because of it, but decided to look for a Pico suction cup and build my perfect Pico drop checker myself. This has to be improved!!!

As others have already described, it's a bit tricky to fill because of its shape. Visually, though, it makes quite an impression.
However, because of its size I would rather use it in larger tanks. It was actually meant for my 50 l scape and looks quite bulky there. That's why it was "relocated" to the 300 l tank.

Well made and the most beautiful CO2 checker so far. A bit fiddly to fill, but no problem with a small syringe and soft airline tubing.

I'm thrilled! Looks fantastic, easy to fill/mount and a great suction cup.
Simply perfect!!! I'll definitely buy another one.

I now have 2 of these nice, simple and unobtrusive Orb Checkers in my tanks and am, by and large, satisfied!

Two minor points of criticism: because of the clear glass, the color of the test fluid can be hard to read, especially when the water is slightly discolored by humic acids etc. It would have been nice if, for example, the filling tube had been painted opaque white, then you could see the color well there against the white background.
The second point is the somewhat awkward cleaning, because you can't simply drain the test fluid and the rinse water out of the glass sphere. No matter how you turn it, a bit always remains in the sphere. But you can help things along with a pipette and cotton swabs.

All in all - especially at this low price - a thoroughly worthwhile purchase!

Design-wise something different. I have 2 of them, one in each 30 cube. Size-wise it's at the limit in a 30 liter tank. In even smaller cubes it's surely oversized.
Fills well and is easy to read.

This Orb Checker not only looks good but is also easy to handle. Maybe not so recommended for small aquariums under 30 L, as it can look a bit big.

Very nice and elegant. Just right for a nano cube. Filling is very easy, too. Fast delivery and good quality, as always.

The shape differs a bit from the ADA knockoffs. I like that.
It works, looks nice, is easy to use and the included suction cup holds rock solid!
Very good product!

Well, what more is there to say, I think the value for money is great and I really like the little Orb Checker. Quality is right!

Visually something different from the usual CO2 checkers. I find that very pleasant. Filling the indicator fluid is a breeze with the right tools.

I toyed with the idea of buying the drop checker from Gush for a long time, but 25 euros was too much for me. Now it's here, the Orb Checker from Aquasabi.

- easy to read
- easy to fill
- great workmanship

Shipping very fast, as usual.