Eheim Wet and Dry Filters Guide
Modus Operandi
The float is the only mechanism which changes the water flow from the spray bar. The pump motor runs at Full Speed : ALL THE TIME.
When newly installed the filter will fill in about one minute or less. Check this time and make a note : as time goes by and filter starts to get clogged with detritus, this time will increase. When filling time reaches 3-4 minutes then cleaning should be carried out.
Filter Positioning
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 absolutely vital to guarantee the correct rhythmic functioning of the wet & dry filter
Feed and Return Hoses
Ensure that the two hoses are same length (cut to adjust if necessary) and they are laid out smoothly with no kinks. During use it is also important to regularly check the hoses for furring up. Any restrictions here can affect the functioning of the wet & dry cycle.
Breather Hose
The breather hose must be positioned in the tank with the outlet un-obstructed and clear of the water's surface. Ensure 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.
Hose Fittings Supplied
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.
Filter Media
Use of incorrect filter media, extra fine foams or filter wool, or the correct filter media packed too tightly or if it is clogged with detritus : all these will affect the wet & dry cycle.
Loud 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. Filling time should be adjusted to approx 30 seconds.
Filter will not fill with water
The pump empties the filter - the float drops - but filter will not refill. Usually a sign of clogged hoses or media. 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 : Filter will not Empty
Pump may also be very noisy. Possible that solid rod has 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
Replacing Spray Bar with Diffuser : likely to cause increase of back pressure on outlet hose, which produces a reduced suction to the float which allows it to rise with only 2 inches of water in the filter.
Reducing curve on shepherds crook inlet pipe : causing a kink in pipe and reducing flow by up to 70% : so float rises with only 1 inch of water in the filter.