Skimming Problems

The skimmer is not working as it should: 1. The skimmer produces too much foam and water. 2. The skimmer does not produce foam. 3. Bubbles come out of the outlet or around the venturi.

Introduction

1. Is it a pump problem? The problem causing excessive or insufficient skimming is almost never related to the pump. 2. Is the skimmer broken? No. If the pump is working and is drawing in air and water, it is not broken. Skimmers are strongly affected by the surface tension of the water. Any variation interferes with the quantity and type of bubbles formed inside the chamber. Water conditions are influenced by many factors, and finding the cause of the problem requires patience and time. 3. Is the pump rotating backwards? Absolutely not. The pump rotates in both directions and, by design, can never operate backwards. 4. Is it a pump problem? The bubbles that appear to come out of the venturi actually come out from the open area between the venturi and the acrylic chamber. 5. After an adjustment or a change in the aquarium conditions, it is normal for the skimmer to release many microbubbles. This is a temporary effect, aesthetically annoying but not dangerous for the animals. Install a level baffle in the skimmer compartment of the sump to prevent the microbubbles from reaching the return pump, or rotate the skimmer outlet so that it does not direct the bubbles straight toward the pump.

Low Salinity

The skimmer cannot operate in freshwater. Even salinity that is too low compromises the formation of the bubbles required for foam fractionation. In addition, adding top-off water too quickly or too close to the skimmer can destabilize its operation for several hours. Solution: Add top-off water after the skimmer and maintain the salinity between 33 and 36 ‰ (parts per thousand).

Lack of Patience

If the aquarium has just been set up, is in the maturation phase, or if recent operations have been carried out (moving rocks, cleaning sediments), it is normal for the skimmer not to work consistently. The same applies if the aquarium is too clean, still without animals, or if it is undersized compared to the installed skimmer. Solution: Patience is required. Do not carry out modifications, cleaning, or adjustments: wait for the aquarium to reach a stable equilibrium. This process may require several weeks.

Mechanical Problem

If the venturi is clogged, insufficient air enters, causing an imbalance between air and water inside the skimmer chamber. Solution: Thoroughly clean the venturi and the entire air intake system, making sure that the air passage hole is free from deposits or debris.

Water Contamination

Many substances can inhibit or alter foam production. Solution: Clean the equipment and use activated carbon for a few weeks to remove the unwanted substance from the water. The contamination may be caused by: 1. Use of cements or adhesives. 2. Use of new plumbing, especially for the inlet and drain lines. 3. Installation of new pumps, chillers, or other equipment. 4. Use of sponges, filter socks, or filter media, including roller mats. 5. Painting work in the room, creams on hands, or cleaning products. 6. Candles or air fresheners. 7. Dosing bacteria, bacteria, or bacteria! 8. Food (including frozen food), supplements, or specific salt mixes. 9. Dosing buffers, salts, supplements, amino acids, or treatments.