Modifing the Coralife Super Skimmer CSS

Saltwater Skimmer – Coralife Super Skimmer

I have created this page to make it easier for people to find fixes and mods for their Coralife Super Skimmers. I went thru all of the Reef Central post, and took out sections that I thought were useful. I have moved the pictures to be hosted off my server since I cant direct link to RC Gallery pics.

Here is how I have mine setup for about a week, while I finish my sump.

Skimmate @ 36hrs

Model: Needlewheel-up 65gal w/ pump
Size: Skimmer is 4 1/2″ x 5 1/2″ x 20 3/4″ high.

Model: Needlewheel-up 125gal w/ pump
Size: Skimmer is 5″ x 7 1/4″ x 24 1/2″ high.

Model: Needlewheel-up 220gal w/ pump
Size: Skimmer is 6″ x 8″ x 25 1/2″ high.

Model: Venturi-Up to 220 gallons pump not included
Size: Skimmer is 6″ x 8″ x 25 1/2″ high.

User Manual / Installation Guide (8.2MB Acrobat File)

For all you people with extra microbubbles or collection cup overflows, a fellow Canadian reefer emailed Coralife about their problem. Here is their response, which might be helpful. I found that this was my problem when I setup my 220.

Thank you, for your most recent purchase of our Coralife Super Skimmer. We are sorry to hear about your experience with our product. It does sound like the skimmer is not set up properly though. The way you wrote your email I understand that you are probably having water come out the air vent on top of the output tubing. If this is the case it sounds as if the bubble trap is not set up properly. You will want to make sure that the top of the bubble trap is at the same level as your water line of the aquarium or 1/16″ above. Make sure your black sponge is on top and the white sponge is on the bottom. Then make sure the end of your outlet tubing is no more than 1/2″ to 1″ in the black sponge (you may have to cut the tubing). What was happening is the skimmer had back pressure on the outlet hose. Since protein skimmers are not pressurized system the only way for water to get out is through the collection cup. That is probably why you where having problems. The other item we include with the model 65 Super Skimmer is a flow control valve. If the outlet is set up properly and you are still having problems attach the flow valve to the outlet of the water pump and valve it back a little. Is your output tubing under water? If so that could be some of the problem. The only way for water to go into the collection cup is because the output has back pressure on it and its not able to get rid of the water going in the unit. The only other problem I can think of is if you do not have the tubing going out and down right away this will also cause back pressure. The output tubing can not run horizontally. Otherwise if none of this is the problem then you can either return it to the company you bought it from or return it to us for a replacement.

Yes cut the tube and place the pump as near to the surface as possible. Everything deeper than 2 inch is too deep. I bet that the waterlevel in you tank is very high?? Only about 1-2 inch below where the skimmer is mounted. Keep in mind that the minimum waterlevel inside the skimmer is at least at same hight as in your tank no matter how open the valve is. If your skimmer is still overflowing when you set up the pump, try to reduce the pump by placing a small pvc fitting inside the tube of the pump. I guess that you have a RIO 1500 or so running on that skimmer?? This pump is too strong when you have very high waterlevel in your tank even if you open the valve completly it is not enough to drain the skimmer.

Ive done away with the flex tube on mine and added a gate valve and bigger vent on the output this seemed to help greatly skims more consistant!

here is a mod I did to the vent to help it get more air works great!!! way better than the plastic hose with a pinhole in the top of it

In a venturi the air is sucked in after the pump(via a venturi valve), in a needlewheel the air is actually sucked into the pump intake, and the “needles” of the needlewheels impeller chop up the bubbles into much finer bubbles. Finer bubbles= more surface area = more protein can stick to each bubble = more effiecient.

Wet or dry skimming is preference I think. Most folks with barebottom tanks generally wet skim. The skimmate is lighter in color, not as smelly but you get a lot of it. Dry skimming will produce dark, foul smelling skimmate. But less of it.

Wet skimming is generally considered to be better in that you are taking more out in the long run at a faster rate, however you are also wasting a little more water as the skimmate is not as thick and condensed.

I did cut the flexible output tube a bit so it can fit a little better in the bubble diffuser box. Try not to have that output tube go below the water line. If you do that, it will make the skimmer level pulse or cavitate a bit. I did replace that white filter with some of that blue cut to size filter pad that you can get at Petsmart. The white filter clogs up easily and causes to make the water level in the bubble diffuser to overflow. I also drilled out that little hole on the output tube a little bigger. As of last week, I put some carbon in the diffuser box to see if this was going to be a problem. It has been working great so far. So, the bubble diffuser box is a good place to put carbon in.

I also put airline hose over the nipple- so it got rid of the sound immediatly

Several people, including Anthony Calfo, suggest keeping the skimmer pump as close to the surface as possible.

I got my pump about 2 inches below the sump waterline directly under the overflow hose output. This is were I get the darkest, nastiest skim I can get out of the CSS.

I normally leave my foam level about 1 to 1 1/2 above the base of the cup.

Since the skimmer is an up, over and down feed, try to have the pump as high to the sump surface level as you can. I have my pump about 2 inches from the water line.

I have been reading and getting some pms from you CSS users about the splashing noise and microbubbles in the tank. SO, i thought about it and did some minor mods to the CSS. The result did reduce the splashing noise and microbubbles, BUT NOT 100%. Its pretty significant though. Heres what you need.
1″ PVC TEE slipxslipxslip
1″ PVC (about a foot should do it)
1″ PVC slip cap
Mag 2 to 7 pre filter sponge.(or equivalent of it)


If you cut all your pvc straight(or should I say square), you shouldnt need any glue. I didnt get any exact measurments since theres different setups among us.


Also what is not pictured is on the pvc slip cap, there is a 1/4 inch hole. You WILL need the cap or it will be really loud.


So not only it reduce SOME noise and bubbles, it also eliminated that big diffuser box that everybody loves. Ive only got this setup for 1 hour so I am not sure how performance will affect it.

one thing i haven’t seen mentioned yet, is details on the pump used on the 125 – the 65 uses a rio 1100, and the 220 uses an unlabeled taiwanese pump, but can anybody confirm anything regarding the 125’s pump?

Only thing I added was airline tubing by the return.

I noticed that the venturi had collected quite a bit of calcium. Cleaned it out and the skimmer started working wonderfully again.

I got a 1 inch cpvc female adpter and put it in place of the flexable hose it goes on tight but it went on mine great then i use 2 one inch 45 to make a 90 turn short pice of pipe one inch couping the i got a pre filer spounge and put it on the coupling it worked very well after the skimmer broke in tho i have very little bubbles any whey i also had leaking when i had my water level up into the neck mine was leaking from the collection cup around the grey ring i ran some # 33 acrylic glue around that ring and i have no leaks now. Later i did a gate vale mod on mine made adjusting much easier let me know if are interested in how i did that and i will let you know.

I would move that pump to about 1 inch from the water surface to the intake.

return hose 1/4″ from water.

I also changed out the filter media that come with the diffuser and replace it with a black sponge that is a just little finer (not fine) and it solve the microbubble issue and an airline where the little knob at the return at and it stopped the sucking sound.

ItemFirst, your skimmer really will need some time to break in properly. The manufacturing oils left on the plastic are detrimental to the operation of the skimmer and need to be dissolved before it will start operating properly. Under normal operation this can take 24-48 hours. You can reduce this time by running it through the dishwasher (not the pump!!) to remove the oils.
ItemIf you are running your skimmer in HOT (hang-on-tank) mode, the instructions tell you to submerge the pump 8″ below the waterline. This is far too deep to get proper bubble production. Cut the plastic tubing so that the pump is only 2-3″ below the water’s surface. This will cause more air to be drawn into the venturi and increase bubble production.
ItemThis tip can solve THREE common problems that I have seen with this skimmer: Excessive microbubbles escaping into the tank, water leaking/shooting out of the output tube vent hole, and irritating water level fluctuations resulting in inconsistant skimmerate production. Cut the flexible output tube so that it is NOT submerged in the water. The stock tube is too long and it reaches it all the way to the bottom of the diffuser box, causing massive backpressure and tons of bubbles to flow into the tank. Cut it so the end extends just into the bubble diffuser sponge (which should be slightly above the waterline anyway).
ItemPull the black sponge in the diffuser box so it is about 1/4″ above the edge of the box itself. Along with tip #3, your output tube should extend into the sponge, but not below the water level in the center hole. This will prevent bubbles from flowing over the top of the sponge and into the tank.
ItemGot backpressure problems or water litterally shooting out of the output vent hole? Drill out the hole so that more air can escape from the tube. You can also slice the nub off entirely and drill out the hole that way. Though depending on how much return flow you have, this may cause a bit of splashing/spray from your hole.
ItemBe PATIENT! This is a great skimmer for the cost, but it does require some attention to get it working properly. Make small adjustments to the red knob and wait and see how your adjustments affect skimmerate production.

Somemore tips that I believe maximize performance for sump use:

ItemHave the skimmer pump as high as you can. About 2 to 3 ” should do it.
ItemSomebody correct me if Im wrong, but try to maximize flow in the main tank. I think increasing flow helps push up all that gunk up into the overflow and sucked up by the skimmer.
ItemHave your skimmer pump as close as you can to the overflow output.
ItemOkay, next tip is not a sump use tip. If used as a HOT, try to maintain the water level in the main tank constant. During the summer days, evaporation rate is gonna be pretty high. An auto top off can cure that. Also having a sump leaves the water level in the main tank constant(just make sure you check the water level in the sump daily)

I had these problems when I added my sump (already had been using CSS Hang On Tank).

Itemthe new water added from the sump increased the total volume of water in the system which in a way simulatea a huge water change. Give it a while to settle down could be 2 weeks.
ItemHave the skimmer pump about 2-3 inches below water. I have mine right next to the overflow intake and it is skimming some really dark nasty stuff.
Itemmake sure the skimmer is level. I had mine unleveled and it leaked at the adjustment knob and didnt skim. I then made sure it was level hanging off the back of the sump. If you have it in sump mabye try to have it hang off the back. it seems to work better that way.

The valve fits between the pump and the clean tubing but is not necessary unless you are getting too much flow from the return. and if u want the return to fit better in the bubble diffuser you can move the part that hooks on to your tank on the main body of the skimmer down a bit so it sits higher on your tank.

If you just installed it, set the foam level really low for a couple of days. It could take up to 48 hours depending how well you rinsed it. Once you see some skimmate, raise the level a bit. Keep doing this daily till you are satisfied with the skimmate it is producing.

Tried the sponge pad (supplied with the skimmer) underneath the diffuser sponge – that resulted in inconsistent bubble level in the riser tube. Tried putting some floss underneath the same sponge – that produced bigger bubbles coming out of the bubble diffuser box and inconsistent bubble level.

This is what eliminated the micro bubbles – I placed the grey sponge vertically in the diffuser box with the return tube resting on top of it (I had to cut some more of it off). Virtually no noise, consistent bubble level in the riser tube and very few micro bubbles (just a few in immediate vicinity of the diffuser box) and some nasty smelling skimmate . BTW, the edge of the diffuser box is about a 1/4″ from the water surface.


Skimmer pumps are better up higher. The protein or scum that a protein skimmer skims is actually lighter than water so it floats to the top. Having the pump 2 to 3 inches below the water line helps suck in that gunk since its higher up. This is especially important on skimmers that are used as a HOT.

47 thoughts on “Modifing the Coralife Super Skimmer CSS

  1. Hey, I recently purchased the 65 gallon model of the Coralife Super Skimmer and am not having much luck with it. :( My only problem is that as soon as I turn it on, foam rapidly starts to over flow into the collection cup. The water level in the skimmer body is as low as it can go and it is still overflowing. the only thing the red adjustment knob seems to do make it do right now is… overflow a lot… or overflow even more lol. I’ve had it running for a couple days now and i’ve been making the clear perfectly clean water it has been producing run back into the tank with the drain tube.
    There are only 20 pounds of pretty well cured rock in the 46 gallon tank that i set up a week ago i don’t really think that there are too many impuritys in the water (my ammonia is 0 so i don’t think it has started to cycle yet). To make maters worse, the skimmer came to me without the adjustment valve that hooks up to the pump that is sosposed to be used to the break in period. I am wondering if I really do need this as it seems there is just to much water flow running through the skimmer. I have already done what I can from this site but any more help would be great as nothing is seeming to help my problem right now

    thanks alot – Jared D.

  2. To Jared,
    Your tank is so full of impurities that the skimmer is going crazy. Keep the red water adjustment level set as low as possible for now and put you clear over flow tube in a 1 or 2 gallon pail to catch all of the skimmate. The skimmer will calm dowmn in a day or two then you can adjust the red water level up higher. Eventually you will not need the pail to catch the skimmate and the skimmer will work as designed.

  3. I have been running the 65 gallon super skimmer on a 45 gallon tank in the H.O.T. mode for about two months. Last week the skimmer started to overflow out of the vent hole, I had make several adjustments and it has since overflown twice. On all occasions the collect cup was less that a 1/6 full the night before and had not been touched in a couple of days.

    Hopefully the problem was the the collection cup was mounted more than the recommended height of 1/4″ above the water level and causing a high back pressure.

    Personally after these problems I would not suggest this skimmer in the H.O.T. mode, as any evaporation in your tank or other problems could cost you a lot of money in floor repairs etc.

  4. Jared,

    You may hav already found a solution since it has been a couple of months. I thought I would post for others.

    I also purchased the 65 model, I moved the grey ring down several inches away from the collection cup, this changes the water level in the skimmer (I didn’t want to lower the water in the tank). Now my knob will adjust the proper way. I can minimize the flow enough to keep running even when I remove the cup for cleaning. It is a great skimmer, With the additional oxygen in the tank, it relieved my fishes stress so much that they were able to fight back against ich, my fish were completely covered.

  5. So I’ve had the same problems people were mentioning with the 65. I have had it for several months and had the initial overflow problems, even with the red adjustment valve closed. For whatever reason it started working–no problem. Then, every time I shut things down for a water change, it would go back to massive overflowing. I checked everything, and the one thing I discovered, if I cover the “vent hole” from the drain elbow, it completely worked fine. Has anyone had this problem and if so, what would happen if I just put a rubber cap over the “vent hole”? My setup is in sump with the output going into my collection chamber. Thanks in advance.

  6. Hello,

    I have just installed this skimmer for the 65 gal. on my 20 gal. I currently don’t have fish, but I do have blue legged hermit crabs. I have tried everything mentioned, but nothing works. It’s set on the lowest setting, lots of bubbles in the collection chamber, noisy, diffuser (pretty much cut as much off as I could) sends out tons of bubbles and overflowed, I also have the clear tube sent in box attached to the drain valve draining back into my tank as to keep the collection cup from overflowing. I don[t want to turn it off and hinder the break in, but I can’t help but think there’s something I can do. Yes, I do have the water level in my tank fairly high as I just topped it off when adding the skimmer. However, everything on the skimmer is as high to the top as I can get it. The water/bubbles in the collection cup is also clear. Any help or thoughts would be greatly appreciated as I’m having hand surgery next week and won’t be able to get my hand wet for 2 weeks after that and want to have this fixed before my surgery.

  7. Hey, I recently purchased the 65 gallon model of the Coralife Super Skimmer and am not having much luck with it. :( My only problem is that as soon as I turn it on, foam rapidly starts to over flow into the collection cup. The water level in the skimmer body is as low as it can go and it is still overflowing. the only thing the red adjustment knob seems to do make it do right now is… overflow a lot… or overflow even more lol ..,yes i got the same problem as Jared.. can u please jelp me thanks.

  8. Due to space constraints I am considering placing my 125 skimmer in the return compartment of my sump. I would put a longer tube connecting the powerhead to the skimmer to extend it into the inlet compartment. This tube would be 30ish inches long. What is this going to do to the performance of the skimmer?

  9. it seems i’m actually having quite the opposite problem with my skimmer… i have had my skimmer for a few years now and it has been working flawlessly up until just recently. i recently bought a aqueon proflex sump and got it running about a week ago. my problem is not that its over flowing, its actually not pumping enough… the valve off my pump is open %100 and my adjustment valve is about %95 open and the micro bubbles are just making it inside the cone. i find that the bubbles will also fluctuate in level from time to time. im not sure if this may be caused by the flexible tubing length or perhaps the water level in my sump. my goal is to have the micro bubbles at a comfortable level without having the adjustment valve maxed out. any help would be greatly appreciated, thanks in advance.


  10. Follow the air tube down to the airtube intake where the air gets sucked into the skimmer pump intake. That little hole can become clogged with rock hard calcifications. I had to carefully drill it out and even widened it a little. Also drilled out the two holes on the silencer a little bigger so they could suck more air. It works great now.

  11. yeah that was the first thing i checked but still now luck. Not to sure which Silencer your talking about?? or the two holes on it..

  12. I am having the same problem with the newer version 65 where the collection cup just fills with bubbles and overflows. I am at my wits end I ended up dumping out close to 5 gallons of water last night and still as soon as I turn it on it overflows. the red valve no matter how much I adjust it the foam keeps coming through clear and overflowing the collection cup. Please if anyone can help it would be greatly appreciated, before I throw this thing out of the window.

  13. Thank you Tyler,
    Your research is by far the best and most efficient in the whole web, even better than Coralife itself.
    By using the smaller hose for the pump and cutting down the return hose to no more than 1/2 inch into the black sponge. i was able to eliminate (ALL) the bubbles and the overflowing of my collection cup.

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  15. Quite a set up you have their. I currently don’t use a skimmer as I use a reverse osmosis system for my tank, and rarely have to do anything to maintain my tank. Love that convenience.

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  17. I have model 65 a nd can not the micro bubbles to stop filling my. I havr tried new white titers new bcd filters. Now i’m down to floss in-between each flyer working the best so far ,but not happy. could i get more pics of your fliter modification? And any ideas you may hav for me tammy.

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