Aquarium sump: what is it and what is it for?

A sump for an aquarium is a kind of set of equipment for maintaining the required parameters of the aquatic environment. Its difference from the well-known set of aquarium devices (spray-aerator, filter, heater) is that it combines all the useful properties of these devices.

This external device, often called a technical aquarium, completely frees the internal volume of the aquarium from any technical elements, which significantly increases the usable volume, does not interfere with observing the inhabitants and, of course, significantly increases the decorative properties of the artificial reservoir. The sump also allows you to increase the actual volume of the aquarium without any visible increase in size, as it constantly receives water from the main tank. Outwardly, this device is a smaller aquarium with several partitions.

The operation of this complex device is actually simple.

• Water intake from the aquarium through a branch pipe equipped with a nozzle with a pre-filter mesh, which prevents parts of plants or animals (for example, fry) from entering the sump.
• Mechanical filtration is carried out in the first compartment using porous materials (foam rubber, mineral wool, synthetic winterizer, etc.) and allows you to separate coarse dirt that creates turbidity (dusty soil particles, the smallest silt, etc.).
• In the next compartment, biological treatment takes place with the help of bacteria developing in porous materials (expanded clay, pumice, etc.).
• The purified water is then heated to the desired temperature using an aquarium heater.
• In the last compartment there is a pump that pumps the purified water back into the aquarium.
• The water drain is equipped with an aeration system, the water is saturated with atmospheric gases (oxygen and carbon dioxide).

The scheme is even more complicated, for example, a so-called foam column can be added to trap organic residues in the form of foam. It is also possible to equip a compartment with adsorbent material, in which various toxins are neutralized, including nitrogen-containing organic decomposition products. For deeper cleaning, you can add an ultraviolet lamp to the circuit, designed to destroy bacteria. The deepest cleaning, of course, can be achieved in the large multi-section sump typically found for aquariums larger than 500 liters.

The water level in the sump is maintained thanks to a control valve installed on the supply hose. Water from the main reservoir is supplied by gravity, which is why the device is placed under the aquarium.

The weak link in the structure is the gravity flow of water. In the event of a power outage, the pump stops working. Then some of the water from the aquarium can completely drain through the sump. This moment is regulated by a slight immersion of the supply hose to a depth of no more than 1 cm. In this case, when the pump is turned off, relatively little water will flow out.

One of the options for solving the problem is the rear technical aquarium, connected to the main one by the principle of communicating vessels. Place it behind the main body of water, so that it is hidden from the eyes of observers. If there is enough space behind the main body of water, and access to this space is not difficult, this arrangement can be considered optimal.

The flow of water from compartment to compartment occurs due to the special arrangement of the partitions. From the first compartment to the second, water pours from the bottom, from the second to the third from above, and so on. Drilling the glass allows you to change the pattern by arranging the water supply to the first compartment from the bottom, this will help create more efficient filtration.

Calculating the size and volume of a technical aquarium is not that difficult. It should hold at least 10% of the water in the main aquarium, this will avoid overfilling the tank when the pump is turned off and the aquarium is overfilled when the pre-filter mesh of the supply hose is clogged. The system compartments should not be filled more than half in working order.

The efficiency of the sump system largely depends not so much on the volume as on the rate of water exchange, that is, on the power of the pump. However, we must not forget that pumping a large volume of water through a small amount of active elements, their effectiveness will soon be lost. A normally operating sump has to be cleaned from accumulated dirt about once every six months. This is the optimal operating mode for the device. After deep cleaning and replacement of active elements, at least a month must pass to start all biochemical processes for which an external cleaning system is being created.

If the additional volume of the cabinet is limited, or the aquarium is very large, some of its volume can be diverted under the built-in sump. This solution may be simpler, since there is no need to regulate the rate of supply and pumping of water. For such a system, it is necessary to separate at least 10 cm of the width of the aquarium.

Companies specializing in aquarium equipment, of course, did not disregard such effective devices as sump. The capabilities of off-the-shelf devices are often limited to filtration, biological treatment and aeration. However, the equipment produced by these companies makes it possible to supplement the set of functions of the sump, for example, with heated water or chemical filters. A fairly wide selection of such products of relatively small volume is offered by Chinese manufacturers.

In large pet stores specializing in aquarium accessories, you can purchase technical aquariums from renowned European manufacturers.

Some Russian firms make custom-made technical aquariums for both marine and freshwater aquariums. Their specialists can also recommend device layout options. The size of the can is selected in accordance with the wishes of the customer. Ready-made aquariums with pedestals and sump systems are offered by the company Aquarium systems and Arcadia... Technical aquariums are designed and manufactured by a St. Petersburg company Coralreef-aqua, specializing in marine aquariums.

Like many equipment, hobbyists often make their own sump. In this case, the most difficult operation is considered the need to drill glass for the installation of branch pipes... If you have no experience in this matter, you can spoil more than one glass. You need to drill with a special diamond nozzle, at low drill speeds, constantly wetting the drilling site with water and observing the perpendicular position of the drill in relation to the glass.

You can use a ready-made aquarium to make a sump. In it, with the help of a special aquarium silicone sealant, transparent glass partitions are arranged, the task of which is to divide the technical aquarium into compartments.

It must be remembered that reducing the width of the compartments to less than 10 cm is undesirable; this can become the main limitation when installing the sump in a finished aquarium. The partitions should be mounted gradually, one after the other, until the sealant has completely dried. If a technical aquarium is made on purpose, then one of the limiting factors may be the size of the cabinet or rack where it is planned to be installed. Filling the compartments of a finished sump is usually straightforward, as all the components are readily available and can be purchased at the appropriate stores.

Next, see how to make a do-it-yourself sump.