Sorry Scott, I know you've mentioned this before, but can you define what the following actions/functions below do?
Pump
Increase watts/percentage = ???
Decrease watts/percentage = ???
Body (Wedge pipe)
open = ???
close = ???
Is the wedge pipe just to raise the water level of the skimmer? How would I decide between increasing/decreasing the wattage vs. opening/closing the wedge pipe?
How do I "wet skim"? (settings, etc.)
How do I "dry skim"?
Pump
Increase watts/percentage = increases water and air flow into the skimmer. This decreases contact time and increases bubble size. Increasing the pump speed will also raise the water level inside the skimmer.
Decrease watts/percentage = Increases contact time by decreasing flow through the skimmer and also decreases bubble size. Decreasing the pump speed will also decrease the water level inside the skimmer.
Increased contact time coupled with decreased bubble size results in more efficient DOC removal. There is a point of deminishing return with this and every model skimmer is different however each sized skimmer has it's sweet spot range in terms of pump speed.
250 sized skimmers seem to perform best between 36 and 38 watts.
200 sized skimmers seem to perform best between 27 & 30 watts.
180 sized skimmers seem to perform best between 22 & 24 watts.
Much of that depends on the amount of DOC's. Less DOC's typically require higher water levels inside the skimmer to keep the foam head up higher in the neck in order to keep the skimmer producing consistently.
Body (Wedge pipe)
open = reduces water level inside the skimmer lowering the foam head.
close = increases water level inside the skimmer by restricting it's flow out of the skimmer and raises the foam head.
I prefer to use sump level to fine tune the water level as much as possible so that the point of where the bubbles transition to slower moving foam is at the base of neck with the wedge pipe wide open. Then do the real fine tuning with the wedge pipe so that I only have to close the wedge pipe slightly.
To wet skim, first find the best pump speed to create the most solid foam head possible. The raise the water level inside the skimmer either via the sump level or by closing the wedge pipe to lighten the skimmate color. The higher the level in the neck where bubbles transition to foam, the wetter the skim. By raising the level, you are essentially thinning the skimmate. Wetter skim results in increased skimmate production.
To dry skim, find the best pump level to get the most solid foam head and lower the level inside the skimmer to darken the skimmate. The lower the level where bubbles transition to foam in the neck, the drier/darker/thicker the skim. It really is a visual thing as far as what you see in the collection cup. These skimmers are very efficient in the speed at which they remove solids from the water. As such, the DOC's are removed, adjustments may need to be made to compensate for the reduced DOC's. That typically would mean raising the level inside the skimmer slightly s that the point that the bubbles change to foam are higher up in the neck. This adjustment typically requires a very slight adjustment to the wedge pipe by closing it ever so slightly. Drier skim results in decreased skimmate production.
The amount of DOC's in the water has a direct impact on ideal settings. The lighter the load in relation to the skimmer size, the more difficult it is to tune a skimmer dry and keep it consistent. In the absence of enough DOC's for the size skimmer, you end up with bubbles that tend to burst faster at the surface instead of generating thick foam. This is because the DOC's provide the proteins necessary to make the bubbles stick together to form consistent foam. The larger the skimmer, the larger the neck diameter and the more DOC's needed to fill that neck with foam. This is one reason why sizing one of these skimmer correctly is important. It allows you to have more control over the skimmer performance and allows it to produce consistently both wet and dry. If the skimmer is oversized or if there aren't much in the way of DOC's for the size skimmer, consistently maintaining a good foam head is difficult. This necessitates the need to wet skim in order to maintain consistency.