How I Dealt With Oversized Skimmer

Brewtoszek · Oct 7, 2022

After listening to the recent Reef Therapy podcast about protein skimmers i thought i should share with you all what i did to make my protein skimmer more efficient for my setup.

I was having a hard time adjusting the water level so that the skimmer would generate skimate without risking random overflows, it seemed like i was walking a fine line, i suspect because the skimmer is probably too large for my system/load.

I made an insert I could drop in from the top which reduces the volume in the skimmer neck area which has been forcing substantially more skimate into the cup. I've been running this setup since about May of this year and have been really happy with the results. This is not an optimized design, the tube diameter/length was a total shot in the dark, im sure i could tweak these parameters to get further improvement.

Here is a cross section showing how it goes together (Its shown with an o-ring groove on the bottom but i have not been using it - keeping it simple and works fine). Its also kind of nice because i can pull the insert out and clean it without needing to remove the whole cup from the skimmer.

Here are a few pictures of the insert along with a video of the skimmer in operation.

ajjw0828 · Oct 7, 2022

dang man, that is sweet! You should start selling these for the high selling brands! Hell I don't even need one but want one now, lol. Thanks for sharing!

Brewtoszek · Oct 11, 2022

ajjw0828 said:
dang man, that is sweet! You should start selling these for the high selling brands! Hell I don't even need one but want one now, lol. Thanks for sharing!

Thanks! I do have some extra tube leftover, possible enough for 2 more if anyone has a Reef Octopus Classic 202-S or equivalent and wants to give it a try.

burban94 · Oct 13, 2022

Pretty cool, I've done this before in the past using pvc pipe as the insert and some epdm rubber gasket to make up the difference in skimmer neck and pvc diameters.

dmsc2fs · Oct 13, 2022

Very nice!

YOYOYOReefer · Oct 13, 2022

Looks great ... wonder why whoever makes your skimmer used such a wide neck in the first place.
in general big wide necks need big big pumps and big bodies below them to keep a stable foam head on top.

i have turned my old ATB needwheel cone skimmer into a dual mazzei skimmer and reduce the neck size when the pumps failed, it works at least as good as it did with the 2 askol pumps on it.

AlexG · Oct 14, 2022

Another great idea. Thanks for sharing. I used a different approach with my DIY skimmer using a PVC insert so restrict the skimmer neck to increase upflow air pressure. Similar results with a different method.

YOYOYOReefer · Oct 17, 2022

the rk2 skimmer i have has basically and acrylic x inside the cone that helps the foam rise up properly .
thread definately shows there are tweaks to get preformance out of most any skimmer.

Crustaceon · Oct 17, 2022

Cool invention! A trick I used to do to boost dry skimmate output on a small skimmer was to take a small ball valve and place it on the air supply line. I have a pretty extensive automotive background and understand how air volume and velocity is affected by pressure on the other side of a restriction, which is important to getting proper atomization of fuel within a engine. Closing the ball valve on the skimmer line increases the velocity of the air drawn through the tubing, which visibly results in smaller bubbles being created and an increase in the foam "head". My theory is this higher velocity air is being drawn into the skimmer impeller more uniformly and with more energy, which allows it to be more easily "smacked" into smaller bubbles by the impeller fingers. I'm curious how this works on a larger skimmer. Someone should give it a shot.

YOYOYOReefer · Oct 17, 2022

Crustaceon said:
Cool invention! A trick I used to do to boost dry skimmate output on a small skimmer was to take a small ball valve and place it on the air supply line. I have a pretty extensive automotive background and understand how air volume and velocity is affected by pressure on the other side of a restriction, which is important to getting proper atomization of fuel within a engine. Closing the ball valve on the skimmer line increases the velocity of the air drawn through the tubing, which visibly results in smaller bubbles being created and an increase in the foam "head". My theory is this higher velocity air is being drawn into the skimmer impeller more uniformly and with more energy, which allows it to be more easily "smacked" into smaller bubbles by the impeller fingers. I'm curious how this works on a larger skimmer. Someone should give it a sho

YOYOYOReefer · Oct 17, 2022

Its how my 90s quad beckett mrc is, the air inlets are all 1/4 gate valves for precise control it mainly sets the bubble size, all skimmers work like this.. if your pump can keep the solid steady pressure is where it works the best... Iwaki/Pan world type pumps can , and the sequence external type pumps.. not too many dc pumps are that great with pressure.

Crustaceon · Oct 17, 2022

YOYOYOReefer said:
Its how my 90s quad beckett mrc is, the air inlets are all 1/4 gate valves for precise control it mainly sets the bubble size, all skimmers work like this.. if your pump can keep the solid steady pressure is where it works the best... Iwaki/Pan world type pumps can , and the sequence external type pumps.. not too many dc pumps are that great with pressure.

It's rad to hear that. I always assumed there was some room for tuning as far as airflow goes.

Budare · Feb 2, 2023

Brewtoszek said:
Thanks! I do have some extra tube leftover, possible enough for 2 more if anyone has a Reef Octopus Classic 202-S or equivalent and wants to give it a try.

Nice insert,

I have been looking for one for My Classic 152-s. It has a 3.15” neck and I probably need to bring it down to 2”. Can you make more?

Brewtoszek · Feb 2, 2023

Budare said:
Nice insert,

I have been looking for one for My Classic 152-s. It has a 3.15” neck and I probably need to bring it down to 2”. Can you make more?

Thanks! I probably could, i'd need some good measurments of the ID and the thickness of the neck wall(or ID/OD). Do you have calipers you could use to take those measurements?

theatrus · Feb 2, 2023

Pretty nice idea, makes me want to reduce my skimmer neck as well due to low bioloads.

acrojunkie · Apr 8, 2023

Brewtoszek said:
After listening to the recent Reef Therapy podcast about protein skimmers i thought i should share with you all what i did to make my protein skimmer more efficient for my setup.

I was having a hard time adjusting the water level so that the skimmer would generate skimate without risking random overflows, it seemed like i was walking a fine line, i suspect because the skimmer is probably too large for my system/load.

I made an insert I could drop in from the top which reduces the volume in the skimmer neck area which has been forcing substantially more skimate into the cup. I've been running this setup since about May of this year and have been really happy with the results. This is not an optimized design, the tube diameter/length was a total shot in the dark, im sure i could tweak these parameters to get further improvement.

Here is a cross section showing how it goes together (Its shown with an o-ring groove on the bottom but i have not been using it - keeping it simple and works fine). Its also kind of nice because i can pull the insert out and clean it without needing to remove the whole cup from the skimmer.

Here are a few pictures of the insert along with a video of the skimmer in operation.

Do you have an STL file for this? Thank you

Srfnhooker · Jul 10, 2023

I have the classic 202-s and I think the reducer may be right up my alley. I bought a 120g with 40g sump along with skimmer, and lights but have since purchased the IM 75g with sump and stand. About 105g total volume. The 202-s is oversized but I'm wondering if your reducer would allow me to keep and use it. I don't want to buy another skimmer. Any thoughts? Price for making a reducer for me? Plan to start the cycle this weekend if if I can find someone to help get the tank on the stand.