The wet/dry technology of this external canister filter series fills and empties the filter canister regularly. As a result the biological filter material and the useful purification bacteria come into contact with a high level of oxygen. The bacteria work more intensively thus effectuating extremely efficient decomposition of pollutants.

Eheim call it a “breathing“ change-over contact which is regulated by a reliably functioning wet/dry floater compartment. After filtering only cleaned water with high oxygen content returns into the aquarium. These filters come complete with EHEIM substrat pro and are suitable for aquariums with a large stocking and for sea water tanks (sea waterproof as a thermo version as optional equipment).

Operation and Installation

The float is the only mechanism that changes the water flow from the spray bar. The pump motor runs constantly at full speed. When new the filter will fill in about one minute or less. After time when the filter starts to get clogged with detritus this time will increase. When filling time reaches 3-4 minutes then cleaning should be carried out.

The filter should be positioned below the aquarium. The distance between the aquarium water surface and the bottom of the filter must be within 100 - 120cm. This installation height is vital to guarantee the correct rhythmic functioning of the wet & dry filter. Ensure that the two hoses are same length and that there are no kinks. The hoses should be regularly checked to ensure they are clear as this will affect performance of the filter.

The breather hose must be positioned in the tank with the outlet un-obstructed and clear of the water's surface. Ensure the outlet end of breather pipe is not sitting on any aquarium stress support strips. If the outlet is restricted in any way the wet & dry cycle will be affected.  If the filter flow rate is altered by the addition of valves, taps etc, or extra holes drilled in spray bar, the wet & dry cycle is likely to be affected.

Trouble Shooting

Gurgling Sound from Breather Hose. As the filter refills with water the air in the canister is exhausted via the breather hose. If the top area of the filter floods due to partly clogged media water can be carried up the breather hose by the force of the exhausting air, causing a loud noise. Check installation height - if above 120cm the water flow into the canister is so powerful that the top area of the filter floods. Partly closing the intake tap when gurgling is heard should overcome this problem in the short term.

Filter will not fill with water. The pump empties the filter and the float drops but filter will not refill. This is usually a sign of clogged hoses or media, and the pump is pumping the water out as fast as its coming in. The water should always flow into the filter continuously. It does not slow down at any time during the wet & dry cycle, so if the filter does not fill the water supply is restricted.

Float is up and the filter will not empty. The pump may also be very noisy. The solid rod may have dropped out of the ring under the impeller. This allows air from the breather hose to mix with water in the impeller causing the noise. Refit the rigid rod into the ring under the impeller. Also check that the cleaning plug is in place in the pump head.

Effects of Modifications.  1) Replacing the spray bar with a diffuser is likely to cause increase of back pressure on the outlet hose which will produce a reduced suction to the float allowing it to rise with only 2 inches of water in the filter. 2)  If reducing the curve on shepherds crook inlet pipe causes a kink in pipe, the flow rate can be reduced by up to 70%, and the float will rise with only 1 inch of water in the filter.