Setting Deltec skimmer pump speed | D-D The Aquarium Solution
Hi Tony, wondered if i could ask you a quick question in regards to the 600i skimmer.
I have a Reefer 250 and not sure what effect the controller has.
The manual states to use the 3rd speed setting for the 600i
Can you advise what effect the speed setting has?
I currently have it on the 5th setting and the water lever is set on min for a dry skim. I'm currently getting a very dark thick skim.
I tried the 3rd setting but a few days went by with only a tiny amount in the cup.
Tank is lightly stocked with some GSP & a small torch, 1 diamond goby, 1 purple fire fish, 2x baby clowns, 2x cleaner shrimp & 4 red legged hermit crabs.
Many thanks
Dear Chris
Deltec generally advise on a speed setting 3 when setting up the skimmer for the first time to help prevent initial flooding when breaking in . After a week one can fine tune the to meet the requirements of your aquarium.
The speed of the pump will increase water flow into the body of the skimmer but will also increase the amount of air by ratio, this happens due to a higher negative pressure being formed at the venturi stub as the higher velocity of water passes by it thus pulling in more air. 
At each adjustment of the speed setting the ratio of air to water will remain more or less constant but the higher the pump speed setting the more water and air will be introduced into the body of the skimmer.
Once you have set the speed of the pump you then need to set the water level inside the body/neck for your desired skim , either dry or wet depending on the bubble break level height. Each time you change the speed of the pump you will need to adjust the water level back to the previous height in the neck if you wish the dry/wet skim to remain the same as the previous pump setting. 
The reason for the different pump speeds relates to the nutrient loading of the tank, when using the skimmer on a tank with lower stocking one would set a lower speed, the lower speed would equate to a longer dwell time within the body and increase the efficacy of low nutrient removal. In a higher nutrient system the dwell time wouldn’t be so important as the higher nutrients would be more available to the skimmer/easier to skim out so one would favour bulk through put over dwell time.
In each situation the water level would be a final adjusment for your prefered wet or dry skim however as already mentioned regardless of the pump speed set. 
Hope the helps Tony