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Skimmer Mesh Mod

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  • Skimmer Mesh Mod

    I have a DIY 12" x 24" body skimmer with a 4" x 8" neck.
    It runs 2 x 3700 Ocean Runner pumps.
    Originally with the needle wheels, I was lucky to get 20scfh.

    I recently mesh modded both pumps and now I am getting 30 scfh from one and 37 scfh from the other. They will pull closer to 40scfh if I lower the water level in the skimmer way down, but I need it to be higher to get skimmate.

    I am using the Enkamat PF4 Flatback mesh. I left one needle wheel on each impeller and zip tied to that.

    It has been running now for about 3 weeks with excellent results. It really sucks the stuff right out of the fishes hind quarters.

    In the process I picked up a RMB-52 and a RMC-101-SSV. The RMC is a Tim Allen special, it is HUGE! and gives very good readings.
    They both read on a scale of 0-50 scfh, this covers most of the small to medium size pumps, but not the dart needle wheel and above.

    I only wish I could get both pumps to pull 37 scfh. They are using venturis based on gate valves so I can fine tune the water flow. The Barb fitting enters just after the gate valve plate on the side.
    I think I need to angle cut the one that is not pulling as much to see if that helps. As I recall, I had already done that a long time ago on the pump that is pulling more, but I don't recall for sure.
    Since it is running so well, I am hesitant to take it apart and look.

    Having been through all of the threads on Mesh Modding and experienced it myself, I have gained a fair amount of knowledge. So let me know if you have any questions.
    This is one way to really make a skimmer perform better without upgrading to a larger size.

  • #2
    Pics man! No good without pictures. No really it would be great to see what you have done.


    • #3
      Believe it or not, I did not take a single picture during the process.
      I do have my spare impeller meshed and can get some pictures of the mesh and the meters.

      The downside being, I did not get the meters until after I meshed, so I do not have any solid numbers with the needle wheels, except from back when I was in my apartment and had a different meter.

      On the upside, the foam head is much better and the smell is stronger. I have also noticed a very slight decline in some of my algae growth. Hopefully the decline continues.


      • #4
        I would love to see a pic of the backup mesh modded wheel!


        • #5
          So Ken, where did you get the mesh at?


          • #6
            The scariest part about this whole project is dissembling the needle wheel.
            I was using this same skimmer at my apartment and I measured it one time with a RMA7 to pull around 18-20 scfh. I have never been impressed with the bubble production.
            After reading a bunch of threads I decided to start with one of the two pumps since I had a backup impeller.
            I ordered the PF4 Flatback Mesh Group Buy kit from I have a bunch left over so PM me if you want some.
            I chose the flatback as one side has been fused with heat making it easier to secure on the impeller.
            since I am using Ocean Runner 3700, the needle wheels are attached with a small amount of glue and have two keys (notches), one on each side.

            You can see the notches in the lower needle wheel on the right and left.
            You can also see that I cut the mesh about 1/2" larger than the wheel to start with. You trim it down once it is all assembled.
            I removed the wheels using a table knife. Slide it gently between them and gently pry the wheel upward. Work your way around slowly.
            Patience is key here. I broke two wheels while removing them.
            If you want to reuse them you will want them in one piece.
            Although different impellers will require different methods.

            Here you can see the zip ties around the spokes of the last wheel. I left this wheel so I had somewhere to secure the mesh. some impellers may require a disc to be created to secure or the impeller blades to be ground down. One spoke broke, so I removed the one on the opposite side to try and keep it balanced.

            In most cases you will want the square zip tie piece on top as clearance on the bottom is typically tight. I left them long until I had everything positioned. Cranked them down tight to avoid shifting and then trimmed them flush.

            This impeller has 4 layers of mesh. This turned out to be too much and I will re-mesh it before using it again. Once the layers are secured, I trimmed the loose ends off as well as trimmed it down to within 1/8" of the end of the spokes. I tried leaving it larger but I had startup issues with the pump. One of my two pumps still has startup issues, but it is pulling 37scfh right now so I do not plan to mess with it.

            Here you can see the two meters. The RMB 52 on the left and RMC 101 SSV on the left. The valve is unnecessary for this purpose. The RMB tends to bounce more so it is hard to get a good reading. The RMC uses a larger ball and is more steady.

            I used four zip ties to secure the mesh. I tried to keep them close to the center to help balance things out and allow the mesh on the outside to flare out more.

            My pumps are rated at 65W. Right now the one pulling 30scfh is running 73W and the one pulling 37scfh is pulling 80W. The Sicce PSK 2500 can pull 30scfh at 22W, but that is a $120 pump.
            I have noted if I drop the water level down the watts go down and the scfh goes up as high as 40. so head pressure definitely impacts performance.


            • #7
              As a general rule, wattage shouldn't go up. You might want to try a layer less or trimming slightly.


              • #8
                I did not put the kill-a-watt on the unmodified needle wheel, so I do not know what my starting wattage was.

                I do know that the pumps are running cooler to the touch than before.

                65W is what the pump is rated, so I am running above the rating, but it may be less than before.

                The comment about wattage going up was related to head pressure.
                At about 18" water depth in the reaction chamber, the wattage is only 40W and air draw is 40scfh.
                As I raise the water level to the desired level (bottom of riser tube or 26" height) the wattage increases to 74W and air draw drops to around 30scfh.

                In other words the efficiency of the mod is somewhat diminished by the design of my skimmer. I could get more air in the skimmer if the overall skimmer height was less.
                Or put another way, your numbers may not match mine even for the same pump as the skimmer size and shape can affect both wattage and air draw.

                With 4 layers of mesh at the same water height, the wattage draw was 110W and air draw was still 30scfh.
                I ended up wit 2 layers in this pump and 3 layers in the other pump.

                I could probably trim the mesh a little more and get it right down to spec, but I am OK with over driving the pump by 20% or less. Especially since I suspect I was running higher with the needle wheel based on the heat.


                • #9
                  Gotcha. Yes, its very possibly (likely even) that your pumps were pulling more than claimed wattage. If they're running cooler, you almost have to assume that it's running at less watts now.


                  • #10
                    Another thing to try is using fishing line instead of zip ties. You are decreasing the rotating mass quit a bit this way and i've had much better success ie, lower watts more air switching to line, its a little bit more time consuming but it's worked very well on sedras and ocean runners that i've done.


                    • #11
                      Good stuff Ken. I decided to try this, all be it, a lame excuse for my attempt on a mesh mod and have it running now. Skimming on a Sicce/Xtreme 200 and the foam head is much more substantial in structure compared to the original pinwheel with larger bubbles. No idea on SCFH or skimmate as of now but a worthwhile improvement. Thanks


                      • #12
                        Do you have any noise issues on that Sicce pump? I recently purchased an MSX200 and the thing makes a racket when I put the mesh wheel in. I'm thinking it's the zip ties rubbing. I talked to marine solutions and they said to just let it run for 2 weeks while it "breaks in". I assume that means while the zip ties get ground down. They swear it won't hurt the pump or if it does they'll replace it. I'm interested to hear if you had this problem with your own mesh modded wheel...


                        • #13
                          I did not have any excess noise, just problems with start up, which has been a nuisance since I have had it even with original pinwheel. I just ditched the red bushing.
                          Is your pinwheel shaft still in one piece? I do not think the pump would be affected. This mesh mod is the last resort to forking out money for the purple pinwheel so let me know how you like yours as well.


                          • #14
                            I did not want to use fishing line as the clearance between the wheel and the pump housing on the bottom is very tight.
                            I had heard more than one person say it wore through quickly.

                            The wattage draw is not bad, especially with only two layers.

                            I do have startup issues sometimes, but I never shut it off, even when cleaning the cup.

                            If you have excess noise, check to see if it is balanced. An unbalanced impeller can cause excess noise. It does not take much to throw it off.

                            To check it, tie a piece of fishing line to a pencil and thread the line up through the center with the mesh at the top. It should not lean too much to any side. Try to orient the pencil so one of the square sides is flush with the bottom of the impeller.

                            Personally I think the whole "break in" related to mesh wheels statements are bogus. It will either work straight off or it wont. If it make too much noise, something is off.


                            • #15
                              Mesh modding pumps is a great thing. I have been modding my pumps like this for several years now. Currently I am running a Laguna 1500 meshed with 4 layers. Before that I had meshed gen-x 6000's and sedra 5000's and everyone gainned a large amout of air flow and the bubble size in the necks of the skimmer became much smaller. Mavgi on RC was a huge help in spreading the word on mesh modding, he was even sending out samples of the enkmat 4. I am pretty sure he is the main reason it caught on so well with hobbiest since he sent so many samples out and tests so many different pumps. I know he helped me several times on skimmer related things. One thing about the mesh is you have to find a venturi for your pump that works well with the amout of airflow the impeller can draw. If not it will hurt your performance more than helping it and be very loud.