We have never tested such a powerful skimmer yet! We measured over 1.300 l/h of sucked air, never happened before this ATB Medium Size of 25 cm of diameter.
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First of all we want to remember, in particular to those who don’t know, that ATB is the acronymous for Aquarium Technik Burian, an Austrian company and its head quarter is Czech Republic. It produces accessories for marine aquarium since 2001. We tested the skimmer in a 600 liters aquarium specifically dedicated to hard corals with small polyps, in particular Acropora. The aquarium is Jonathan’s beautiful one, that you will have the chance to see as aquarium of the month in these pages… and a glimpse in this very article.
As usual we tried the ATB Medium Size 25 for several months, so that we could know every pros and cons. We can affirm that, even thanks to the provided accessories, the skimmer really amazed us. The automatic cleaning is addictive right from the start, and the power of the skimmer is simply incredible.
Speaking of the assembling the skimmer doesn’t hide its artisanal origin. Beautiful, well built, but it doesn’t shine compared to other skimmers we’ve recently seen (Ultra Reef, Red Sea, Vertex, Nyos for example). The declared sucked air is 1.500 l/h while the treated water 2.500 l/h, for a air/water relationship of 0,6 with the Askoll pump.
Technical characteristics of the ATB Medium Size
| ATB with pump Airstair | ATB with pump Askoll | |
| Treated water volume | 2.800 l/h | 2.500 l/h |
| Treated air volume | 1.500 l/h | 1.500 l/h |
| Pump consumption | 38 w | 38 w |
| Dimensions | 390x340x560 mm | 390x340x560 mm |
| Water height in sump | 18-19 cm | 18-19 cm |
| Warranty | 24 months | 24 months |
| Price | 980 euro | 980 euro |
Construction
The construction is very well done, there are minor flaws, but nothing that could affect the yield. Even though there’s a little detail… but we will discuss about it later, because it regards the cleaning accessory and not the skimmer itself.
About the functioning, we have an old style set that suits more the powerful pump that these diameters requires. In fact the pump is external, so there’s more space for the bubbles in the body of the skimmer. The pump pushes inside the central body where the water and the air mixed together are pushed through the perforated diffusion plate. The central body is conical. The pump in question is an Askoll that draws at many cm from the bottom of the sump.
The body of the skimmer had a diameter of 25 cm and it’s almost 56 cm of height glass included.
One of the added value of this skimmer is the possibility to buy an automatic cleaning system, built with a little brush implanted on a pivot, that is activated via a timer (not provided) that keeps the neck of the glass perfectly clean. Thanks to this you only have to empty the glass through the inferior cap and… that’s it, without ever disassembling the glass.
The assembling system of the skimmer ATB Medium Size is very simple and it allows to be disassembled in a short time. This also thanks to its dimensions and because the pump is external.
Given the dimensions, the glass is pretty heavy even it sticks perfectly in the base where it has to be placed and pushed a bit. The holding is assured also by a red gasket. At the base of the glass there’s the classic through hole, from which begins the PVC curve closed by a silicon end and a stopper.
The provided pump with the ATB medium size 25 is a Airstair, an adjustable pump of 2.800 l/h of treated water and 1.500 l/h of treated air. In our test conditions there was a second non-adjustable pump by Askoll, to be purchased separately, or to order from Askoll itself, of 2.500 l/h of water and always 1.500 l/h of water. The second should be more quite and with less vibrations. Even if we were thrilled by the double possibility we had to adapt to the dimensions of our sump, so we couldn’t help but try the skimmer with only the Askoll, that is the only pump that could fit the room available.
Being a monopump configuration we don’t have to manage the water entering the skimmer and the water/air relationship because they’ve already been decided in our place. The suggested level in sump should be about 20 cm, managing heights between 18 and 24 cm, as the builder designed.
The functioning scheme is, as we’ve said, simple and linear, even more compared with other skimmers we’ve recently reviewed. Moreover, this ATB has an external pump that allows to use more volume of the body of the skimmer, rather than in configurations with internal pump, increasing also the contac time inside the cylinder. The comfort of the external pump is given when it’s time for cleaning. Water and air are mixed together and, from below, they enter directly in the body of the skimmer. From here they pass through the classic perforated plate.
The only way to intervene on the calibration of the skimmer is to rotate the drain pipe, which adjusts the slider that determines the level of water inside the body.
Set up
The set up is pretty complex, it doesn’t depend on the skimmer itself but on the various accessories, that anyway have to be purchased separaterly. The brush inside the glass has to be assembled, the float inside the glass has to be connected to an external controller that will then switch off the skimming pump when the level in the glass is dangerously high.
The article continues on page two with the functioning, the performances and our measurements on field.
