Used and Abused: TMC Reef-Skim 500 Skimmer


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TMC REEF-Skim PRO 500 Skimmer

Tested by: Gabor Horvath

Duration: 2 months

Price: £229.99 


Reef tank keepers know very well that a reliable skimmer is a must for maintaining a healthy marine aquarium. There’s an ongoing debate about the best skimmers available and one brand’s name keeps popping up quite frequently.

I took it upon myself to check out what the hype’s all about so I put a TMC REEF-Skim PRO 500 DC protein skimmer under a rigorous test and took it apart (literally) to pieces. Here’s what I found.

Protein skimmers went through a serious development in the past few decades, especially given the way that modern saltwater aquarists expect a lot from their equipment. They don’t want operations that are too complicated, but a good skimmer still has to provide adequate controllability for the users to generate the desired skimmate quality. This in turn is achieved by incorporating both water- and air-flow adjustments. A decent skimmer needs to produce sufficient amounts of very fine bubbles and allow long contact time for efficient protein binding. It shouldn’t take too much space nor be expensive to run. And it needs to be easy to clean.

I can confidently write that the TMC REEF-Skim PRO 500 has solutions to all of these, but before going into detail let me begin with my first impressions. Upon opening the box, I was greeted by a lonely collection cup, but under the cup I found a fully assembled skimmer, which was ready to use straight out of the box — no assembly is required, which will be a considerable relief to the less DIY-enthusiastic aquarists. 

Still, I personally find it quite enjoyable to put together new equipment, as it helps me to better understand the operation of it and makes any future maintenance much easier. Therefore, I took everything apart, so I could get into the ‘soul’ of this skimmer. 

Disassembly is remarkably easy: there are four plastic screws (which you can easily unwind by hand) fixing the conical body to the base plate. Some critics may find these screws to be a bit ‘plasticky’ (well, they are) and cheap-looking compared to the fancy metal screws in some other skimmers, but not needing a tool to unscrew them counts for more to me. 

After detaching the piping from the pump unit, the skimmer body can be lifted straight up, which gives you access to the unique double diffusion plate, which is there to disperse microfine bubbles. 

The whole assembly can be easily removed by sliding the pump unit off the base-plate. With a small twist the rotor house can be taken off, giving you access to the heart of the skimmer: the bright red needle wheel tasked with mixing the water with air to create the fine bubbles. 

The wheel is powered by a reliable TMC DC Reef-pump, which I’m familiar with from an earlier review. The pump in this particular skimmer can churn out 1000l/h (max flow) for only 14W electricity consumption, so it’s quite efficient. Running at a low voltage on 24v makes it safe as well, which is reassuring given saltwater’s ‘knack’ for creeping up electrical cables. 

As the DC pump is easily controllable the aquarist can set the optimal flow rate and then adjust it later when it’s necessary. 

The pump also has a ‘feeding function’, allowing you to turn it off for a while when feeding the fish, safe in the knowledge that it’ll automatically turn it back on after a set time (a very useful feature if you’re as forgetful as me).

After reassembling the skimmer, I installed the REEF-Skim PRO 500 in the sump under my marine tank to see how it performed. It took a bit of time for the skimmer to break-in (everyone with a marine tank is familiar with the adjusting period for new skimmers) but after a few days I was able to achieve the required quality skimmate — whether it was dry or wet — by playing with the various settings.

The REEF-Skim PRO 500 allows the user to precisely adjust the air-flow coming through an air-intake, which in turn is fitted with a silencer for quiet operation. The amount of water getting into the body is regulated by a geared control knob, while the optimal flow rate is ensured by the above-mentioned DC pump controller.

The large collection cup is also easily removable for cleaning, but if you’re generating lots of wet skimmate, a hose (supplied) can be attached to it for continuous draining. The maintenance is relatively painless; I can take the skimmer apart, clean the rotor and the cup and reassemble it within less than ten minutes.


Overall I’m particularly satisfied with the TMC skimmer. It works well, has a relatively small footprint, and it’s a solid performer with great adaptability. Purchasing one doesn’t cost an arm and a leg and the low running costs ensure good value for your money. Oh, and I like the blue colour, too!

Ease of use: ****

Features:  ***** 

Value:  ***** 

Overall:  *****