Wolfgang Weidl - is the man behind the Deltec Brand and has spent the last 20 + years developing a range of the most efficient protein skimmers in the world.
If you ask him the 5 most important considerations when developing a protein skimmer he will tell you:
- Air volume
- Bubble size
- Air volume
- Contact time
- Air volume
Air Volume - Skimming works by attracting protein and waste molecules to the air/water interface at the surface of air bubbles in the water. Therefore the more bubbles, the larger the surface area for attraction and the more efficient the skimming action.
Deltec, after years of testing, strongly believe that for every 1000 Ltrs of water in the aquarium you should have 400 - 500 Ltrs of air per hour to achieve efficient skimming on systems with a heavy stocking load.
For example with 200 lts of air, the MC500 protein skimmer we believe is suitable for 360 Ltrs (80 UK gallons) on a heavily stocked fish system or 550 Ltrs (120 UK gallons) on a normally stocked reef aquarium.
All of the Deltec protein skimmers use this quantitative approach to determining the recommended aquarium size and therefore if we say it is suitable for twice the tank volume then you can guarantee that it has twice the air volume and twice the performance. (see the article "skimmer specifications")
Our tests show that many other manufacturers use at least 2 - 4 times less air on skimmers which are claimed to be suitable for comparable water volumes.
This means that either Deltec massively understate their recommended tank size, which we do not believe is the case, or other companies are happy to give guidelines which allow you the end user to accept a lower quality of water.
Bubble size is also important for the same reasons as the smaller the bubble the larger the relative surface area for attraction of the waste molecules.
Example - 1 lt of air would form 1.9 million bubbles of 1mm diameter and with a surface area of 6 sq. m whereas with a diameter of 0.5mm the same volume would form 15 million bubbles and have a surface area of 12 sq. m.
If you halve the bubble size for the same volume of air you will double the surface area.
Contact Time - tests in Germany have shown that attraction at the air/water interface is very fast and therefore contact time only really becomes an important issue when you are low on air volume and therefore each bubble must have a chance to become fully loaded with waste.