Let's Tune Your Reef Tank's New AC or DC Protein Skimmer!

The vast majority of reefers don't know exactly how to tune the protein skimmer. So, here's the guide.

No matter the skimmer, there are only three things that you can control:

The water height of the sump

By changing the water inside your sump, you are subtly changing the pump's head pressure o the pump, which in turn affects the quality of the bubble.

Typically, you want to set the sump water height based on the skimmer factory's recommendation and only change it if necessary. 

Water Height Inside the skimmer body

All skimmers have some water height adjustment valves. When it is wide open, the water pulled in via the pump can easily escape, so it keeps the water height low, but as you restrict the Flow of the water, not all of it can escape easily. So the water is forced upwards in the reaction chamber.

Changing the water height inside the skimmer chamber only raises or lowers the size of the bubbles, but it doesn't change their consistency. 

The amount of air

Changing the number of air changes bubble sizes. Less air means smaller bubbles that hold their structure better and don't pop, called dry skim.

On the other hand, more air means more giant bubbles that tend to pop, and we can do that as a wet skim.

Tuning Your Skimmer

Well, the answer's a little bit different depending on your skimmer, but our overall goal is to create a medium skim, not too wet or dry, that can generally overflow into the collection cup. So with that in mind, let's start with a standard AC-powered protein skimmer.


Start by checking the water height inside your sump. Then, double-check to make sure that it's within the factory recommendations. 

Egg crake works well if you need to raise the skimmer to lower the water height. 

Next, turn your water height adjuster, so it is right in the middle. This way, you'll be able to adjust the water height inside your skimmer in either direction if necessary. Finally, plug your skimmer in; if it's brand new, it can take a week to break in properly.

It'll act erratically up and down during this time, and it will be impossible to tune. So just let it do its things, even if it starts overflowing. 

After the first week, most of the oil sand residues from the manufacturing process will disappear, and it's ready to tune.

Focus on getting the right consistency of the bubble. This can be challenging with any AC-powered skimmer. When the skimmer sits don't at the bottom of the sump, and the water height adjuster is wide open, the water level inside the skimmer and in the sump is the same. 

This wouldn't leave your pump with much head pressure so it can draw in a lot of air through the venturi. However, if your skimmer is sitting on the bottom of the sump and bubbles are constantly overflowing through the collection cup, that's probably a sign that you will need to raise your skimmer up. 

By raising the skimmer and adjusting the water height inside the chamber, you will have a larger size inside the skimmer and a lower sump. This will create more head pressure on the pump since it has to push the water up higher, which will, in turn, mean less air, smaller bubbles, and hence a dryer skim. But you can only take this so far.

Eventually, microbubbles will start escaping out the bottom, and these will end up clouding your water. If your AC skimmer will only produce a wet skim, no matter what you do, and it constantly overflows into the collection cup, that is a good sign that your protein skimmer is too big.

Then it's time to buy a smaller skimmer. Or you can also add a sort of valve to the airline. All the way will create giant bubbles, and all the way closed creates tiny, dry bubbles. Adjust whatever valve you start until you get the right size bubbles.

After a few hours, you'll see the organic line. This will be the point that your bubbles have settled it. If the line is too low, you'll see a dark ring of gunk in the neck, and it would be great if your gunk made its way up a little higher into the collection cup. So close the water height adjuster slowly and push the bubble head higher.

But if you have the budget and want to stay away from all discussed above, you can upgrade to a DC-powered protein skimmer.

Tuning in the DC Skimmer

If the sump is at the correct level, break in your skimmer. Then, open the water height adjustment valve again to keep the bubbles as low as possible.

Next, we're going to find that perfect size bubble, but this time, you have to adjust the power level on your DC pump. Now, change the water height until the organic line approaches the top of the collection cup.


No matter what skimmer you have, remember these two things, the amount of air controls the size of the bubbles and determines if you have a wet skim or a dry skim.

The water height adjuster merely raises or lowers the height of the bubbles, and that's it.

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