Our in depth review of the skimmer LGMAquari Lgs 850

skimmer lgmaquari lgs 850 reviewThe skimmer LGMAquari Lgs 850 is one of the latest offers of LGMAquari in the field of mono-pump skimmers. This skimmer is suitable for saltwater aquariums containing up to 900 liters.

Iquitos - mangimi tropicali - Colombo


The Lgs 850 is built with high quality materials; the construction level has been improved, reaching excellent level of craftsmanship. There are no evident flaws and coupling between white, grey PVC and acrylic is really very pleasant.

skimmer lgmaquari lgs 850 review

The operating scheme is classic monopump skimmer style: external submerged pump picking from the bottom of sump with a brush impeller. The scheme is classic, I’d say, and very well field tested. The skimmer body has 15 cm diameter, 62 cm tall, including glass, for an approx total volume of 8 liters. skimmer lgmaquari lgs 850 review impeller

The cup diameter is larger than the body, being 18 cm, with internal cylinder 10 cm wide. The operative filling height is 12,5 cm, so the cup volume capacity is 2.2 liters, very generous. It’s almost impossibile to fill the skimmer cup, because before reaching the filling level, the cup would gather so much skimmate to impair skimming operation.

skimmer lgmaquari lgs 850 review

The cup fits into skimmers’ body by o-ring coupler. It’ not easy to insert, and it must be pushed in but, mostly, is very difficult to remove, unless you don’t use siliconyc lubricant, not supplied with the skimmer. In this case, the operativity is very smooth and simple. However, tolerances are perfect with no flaws and hydraulic tightness is assured.

skimmer lgmaquari lgs 850 review

On the top of the generously dimensioned cup, there is a closing lid with four air discharge. There is no unwanted leakage, also thanks to the lid’s weight. A nice touch would have been the inclusion of a valve to be fitted to an external discharge system eventually placed close to the aquarium or linked to a little canister, in case of prolonged absence.

skimmer lgmaquari lgs 850 review

The supplied pump is a SICCE PSK 1000, very reliable and used in a huge range of skimmers nowadays. Noteworthy is the air – water mixing system adopted by LGMAquari.The top of the pump is fitted a white pvc extension which lowers the aspiration point towards the bottom of the sump. In the meantime, the air tube is fitted and a practical screw, in white PVC, is used to regulate the waterflow intake. At the beginning, you may want to rotate pump aspiration, first to avoid picking water from the sump bottom and then to better pick from the surface, where nutrients to be skimmed are supposed to be but the builder discourages this practice, because the pump is powerful enough to flawlessly work and in sump there is enough turbulence to be sure that water picked up from the bottom is not noteworthy different from the water in surface. Being a single pump configuration, we don’t need to worry to deal with the water intake in the skimmer and air / water ratio, just pre-configured. The advised level to be kept in sump is more or less 20 cm, with tolerances between 18 and 22 cm.

skimmer lgmaquari lgs 850 review

Despite the lack of dampening under its base and considering the generous pump, the LGMAquari LGS850 skimmer is extremely silent.


Installation is simple, considering the fixed skimmer scheme. The inlet and outlet water tube are fixed and angled by 90° from each other. Normally, this is not a problem, but it’s advised to check your sump before purchase.

skimmer lgmaquari lgs 850 review

As you can see from the picture, the top exit is free. This may normally cause a serious issue with noise, because of water discharge. Then, we have two choices: the first one is to put in contact the outlet with the sump edge, if tall enough, so the glass panel can insulate the water noise. Although it may seem stupid, it really works. Otherwise, we can only buy two pieces of PVC tubes and a curve to insert into the outlet, in order to bring the spill-over slightly under the sump water level. I adopted this solution, as you can see in the following picture. Water level in skimmer’s body can be controlled positioning outlet tube more or less on top of vertical tube. In order to have a good skimming, water level should be slightly over the cup’s base.

skimmer lgmaquari lgs 850 review

It’s also possible to get a more wet skimming by raising the level or more dry by lowering it.


LGMAquari Lgs 850 skimmer has been extensively tested in my 400 liters tank, heavily filled with sps and with many fish (about 35), few of them medium – large sized. I also recently heavily reduced the amount of corals, however, the skimmer has always been very efficient.

skimmer lgmaquari lgs 850 review

The skimmer started working immediately after being inserted in sump. The bubbles are medium – small sized and this is optimum for skimming process and nutrient removal. The supplied SICCE PSK 1000 pump is every powerful and, from an optical point of view, skimming seems optimum.

skimmer lgmaquari lgs 850 review

The manufacturer advises to use the skimmer within a sump level from 18 and 22 cm, even if the skimmer doesn’t appear to be sensitive to the level. Keeping a level of 20 cm improves the efficiency, but in my thank I’ve always worked with a 18,5 cm level, due to construction problem.

skimmer lgmaquari lgs 850 review

The skimmer has been inserted in my tank during a critical situation. The nitrate level was beyond 25 ppm. Phosphate level was around 0.4 ppm. The skimmer, however, has been very reactive, keeping water so clean to reach a paradoxal situation to have nitrates and phosphate in tank but very few nutrients, thanks to the excellent skimming capability of LGS 850.

skimmer lgmaquari lgs 850 review

The usage of this skimmer rapidly and efficiently brought to a marked water cleanliness, absence of particles and more transparency. In order to give you a better idea of the skimming process, I prepared a 48 hours time–lapse, from 9.00 pm of the first day to 9.00 pm of the thirth day. During this timeframe, I gave plenty of food, as usual. Nitrates level were 0,5 ppm and phosphates 0,2 ppm at the moment of the time lapse.

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As you can see, the foam is very soapy and, although skimmer’s level is very high in order to get a wet skimming, the foam quantity is very low, considering also the number of fish in tank (35), their feeding (5-6 spn of ELOS SVM 2) and nocturnal coral feeding witn 6 ml H&O Corals by Sicce and 3 spoon of Sicce Calanus). During feeding, there is a marked change in foaming level, as you can see. Skimmer is very silent, especially after submerging the outlet. I made 3 measurements, all of them 1 meter away from tank and sump, getting the following results: DSC_2723 Acoustic noise at one meter distance with all tank pumps turned on and cabinet closed: 41,5 dB DSC_2722 Acoustic noise at one meter with only return pump turned on and cabinet open: 43,8 dB DSC_2721 Acoustic pressure at one meter with return pump and skimmer on: 45,3 dB. The difference in acoustic pressure with skimmer turned on and off is about 1,5 dB. This value is very low and Lgs 850 is very comfortable from an acoustic point of view. The device used is the usual VOLTCRAFT 320, IEC 651 digital phonometer, type II, very precise. Due to noise nature, dampening curve dBA has been applied.

Performance and measurements

Skimmer’s performance declared by manifacturer is about 900 l/h with air capacity 800 l/h. These values depend from many other variables (height of water in sump: 20 cm) and variations of skimmer’s water column. Air/water ratio is 0,89. In my sump, the water height is 18,5 cm (1,5 cm less than the ones requested by manufacturer), in order to get maximum efficiency, and outlet level is extremely high, in order to get the highest possible water level in the glass to skim as wet as possible.

skimmer lgmaquari lgs 850 review

To estimate processed water, we measured the filling time of an empty container. Five measurements have been made and then an average value has been calculated. Then, we got a processed water capacity of 679 l/h. In order to measure air capacity, we used a Sander fluxymeter, able to measure air from a minimum of a 100 l/h to a max of 1000 l/h. Estimated value are increased by 10% to compensate losses from the device itself.As you can see in the following video, air is sucked in a very irregular way and so, in order to get the final value, we took misuration for each second, calculated the average value and then added 10%.

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The processed air capacity is therefore 494 l/h The resulting air/water ratio was of 0,73 The difference between real and declared values is quite high. Air aspiration decreased by 39%; processed water level decreased by 25%. Despite minding these differences, we remember that skimmer’s settings can heavily affect performances, as we have previously stated.

Maintenance costs

PSK 1000 pump by default has a notable consumption of 57 watt with normal impeller but, with brush impeller and on a monopump skimmer, the estimated consumption is 25 watt, 219 kwh/year, with an estimated manteinance cost of 57 euro based on the price of 0,26 euro/kwh. A very acceptable maintenance cost of less than 5 euro/month.

skimmer lgmaquari lgs 850 review


LGMAquari Lgs 850 is an extremely valid, very well built skimmer, offered at a quite notable retail price (840 euro) but widely justified by its performances. The usage was very regular, efficient, very simple to set and very silent. One little criticism, as we have already noted: you have to find a way to silence the drain and the lack of lubricant. Skimming is very regular, bubbles enough small and the device can flawlessly manage a complex tank like mine with full-size corals and 35 fish, which leads to massively feed. Also, the tank contained a high level of nutrients but the skimmer was able to manage the situation without any problem. We also have to underline that the skimmer, properly and carefully set, can be even more efficient. In my opinion, the device is suitable for a densely populated tank with sps corals and fish (around 400 l) but can be pushed to be used even with larger tanks (500 l) and (in case of tanks populated by fish only or soft corals) even on the edge of 1000 l.

skimmer lgmaquari lgs 850 review
Many thanks to LGMAquari for providing the skimmer tested.

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