Needlewheel to Meshwheel skimmer mod

[Delphinus]

I modified my ASM G3 (Sedra 5000 pump) to a meshwheel skimmer this weekend. Here's what I did:

1) Cut off all "needles" from the impeller except for 4, 1 each at the "12:00", "3:00", "6:00", and "9:00" positions. (My thinking is that this will help prevent "slippage" of the mesh as the impeller turns.)

2) Cut a 3 squares of Enkamat PF4 mesh material, large enough to cover the impeller wheel. Each is 1 layer.

3) Trim the mesh down to the impeller wheel.

4) Weave some fishing line into the mesh to attach. (Some people use zip ties, I thought this might work a little better).

The impeller did not immediately want to start turning, which makes me think I may not have trimmed it back enough. However with some fiddling I was able to get the impeller to turn when the pump is powered on, so I left it. I wonder if 2 layers may have been better than 3 for this reason (well that and one other reason, more on that below the pictures).

http://members.shaw.ca/hobiesailor/aquaria/meshwheel/1.jpg

http://members.shaw.ca/hobiesailor/aquaria/meshwheel/2.jpg

http://members.shaw.ca/hobiesailor/aquaria/meshwheel/3.jpg

http://members.shaw.ca/hobiesailor/aquaria/meshwheel/4.jpg

http://members.shaw.ca/hobiesailor/aquaria/meshwheel/5.jpg


I can safely say that this mod does make the skimmer produce more foam, so I am pleased with the modification (and relieved that I didn't wreck an impeller for nothing - as replacements cost around $50). In 24 hours my skimmer has produced a full-on inch of skimmate, which is hands-down the best it's ever performed.

However, I did some before and after airflow measurements with a 0 to 25 lpm range airflow meter from Muis Controls, and the #'s don't show a difference. Before with the "stock" impeller I read about 5 lpm nominal (with spikes to 10 lpm), which is exactly the same readings as with the modified impeller. So I'm somewhat at a loss to explain why people on RC claim improvements from 5 to 12-18 lpm, however I suppose there are many factors/variables at play, such as venturi design, pump model, how the pump is plumbed, etc. Based solely on the visuals and not the measured airflow numbers, I know the skimmer is producing more foam than before, so I'm pleased with the mod.

However, I am left wondering if this may also be an argument to trying 2 layers over 3, perhaps the mesh density is a little too high to prevent an "even better" air suction.

Over time I may experiment with other air injection methods to see if I can improve on the air flow #'s, but for now I'll leave that as a project for another day. :mrgreen:

[SuperFudge]

Very nice work tony,


I think the real difference, and the reason for the more air claimed on the other threads... is now you should be able to inject the air you need without it cavitating prematurely, on its own i would have even expected a small drop in pull on air.

Now youll get a finer bubble, and more air.

Did you hone out the volute at all ? ( caution again...several people have gone through the housing.)
Doing this should also enable more air to be accepted without burping, while allowing more room for mesh to spin freely.

Is this a recirc version ?

Good job !

[kwirky]

egh, nice to see you had the guts to chop up your impeller without having a spare around ;)

[EmilyB]

egh, nice to see you had the guts to chop up your impeller without having a spare around ;)


:lol: No kidding, I'm hoarding my extra impellers from those bad pumps now....big money $$$:mrgreen:

[christyf5]

Wow Tony, you finally took the plunge! Thank God it worked eh? :biggrin:

One thing I noticed after doing the mod myself (without cutting the needles off the needlewheel cuz I'm a big chicken) was that if you don't have the enkamat trimmed back pretty well on the needlewheel the pump won't start up right away. Even after some generous trimming I find it takes a few seconds for the needlewheel to kick in. The bubbles are definitely finer and the skimmer produces more skimmate than before :biggrin:

This has given me more courage to cut the needles off but I'll still procrastinate some more till I do it :razz:

[Delphinus]

It took me a full on month after getting the enkamat to work up the courage to start cutting the impeller. Even after reading thread after thread, page after page of it on RC and other boards, I was still hesitant (because I find I always tend to be the one exception where things don't work as well as they do for others). I even ended up pulling the sump and reworking the baffles in an effort to procrastinate on the impeller mod. I finally convinced myself by making sure I could order a new impeller.

Marc, no I didn't grind out the volute. I totally envision myself screwing that part up :neutral: .. I'll have to do some reading and see some pictures of it being done before I'll get the nerve to try that. I can sort of see it being helpful, but I totally see me just finding out in the end that I just wrecked the pump.

Wait .. is the volute the cap that goes over the impeller or is it the part where the impeller sits in the pump itself? It occurs to me that I'm not even sure what a volute is. :redface:

And I didn't realize that people were pushing air into the skimmers. So is that a more common thing then? You were the first person I ever heard of who was directly pushing air in, but I thought it was because the skimmer and the pumps you're using are .. um .. well .. somewhat larger than average? ;)

Would any old airpump do? I suppose I could try experimenting with different pumps I've got lying around. I spent the money on the flow meter might as well try to get some use out of it. If I find anything out about how much air I can push, I will post some results in here.

[kwirky]

i remember when reading about building air driven skimmers you have to use non-diaphram air pumps. dunno if it'd be the same case for a force air venturi skimmer

[Delphinus]

The problem there is that the backpressure of pushing air through the wooden airstones is hard on the diaphrams and they stretch out and lose their effectiveness after a while. In this case you'd be pushing air into suction anyhow so it should be OK. Having said that though, I don't know what a typical air pump pushes in terms of litres per minute. It could be that you still need a spendy-ish air pump just to get the requisite volume of air moving into the skimmer. I don't know, but I can assure you I'm wasting my time here at work looking into this very thing as we speak :p

[Joe Reefer]

Tony if you dont mind me asking, How much did the airflow meter cost?

[Jaws]

I'm getting pretty close to doing this mod too so I'm just tagging along to hear everyone's experieces.

Can you use a dremel to cut the needles off or do you think a knife or blade is better?

Where's the best place to order a Sedra 5000 impeller just in case?

[christyf5]

Heh, I was just gonna use a pair of "wire clipping" pliers :razz:

OceanAquatics has replacement impellers in stock. I checked before Tony did his mod :wink:

[Chin_Lee]

Tony
find a drill bit that will make the venturi hole slightly larger but not enough to make it brittle and break. If it does break, push the air line through the hole. here is a pic from Kentrob11 on RC who created a venturi by plumbing a line through a pvc fitting. the narrowing of the water passage creates a venturi. Make sure the angle of the pipe cut is towards the pump's intake.
http://i123.photobucket.com/albums/o309/chin_lee/8543imagdne1.jpg

[fishface]

no pic there Chin...:mrgreen:

[BCOrchidGuy]

Pic worked for me, I have a question, maybe not a very good one but non the less here it goes. With finer bubbles and more skimmate, do you anticipate your salinity will drop as fresh water is topped off to compensate? I know your not taking a large amount of water out but I found my SG decreased when I set the skimmer for wet foam rather than dry foam.

Doug

[Delphinus]

Hey Chin, yeah, actually I went and bought some acrylic tubing a couple weeks ago to try that mod too. I just haven't done it yet because I might have to reconfigure the pump on the skimmer to accomodate the spacing. Basically I'll have to patch one hole and drill a new one.

It seems that most meshwheels have the venturi as vertical. I have my pump oriented that way but the venturi itself horizontal before a 90 degree elbow. I'm thinking that's suboptimal but it's what I could do at the moment.

Nevertheless I'm getting an inch of skimmate every 12 hours. This skimmer has never done so well !! It's a little weak though (think green tea colour instead of the desired Coca-cola colour). I might step my feed pump down to increase the recirculation contact time. Currently my feed pump is a MJ12 (before all this I was feeding it directly via the overflows, .. this seems to be an no-longer-recommended approach .. too difficult to adjust for a consistent foam production).

Doug, yes you're correct, skimming will work to reduce salinity. The effect is negligible though (well .. at least, easy to compensate with your regular water changes) unless you're pulling out significant volumes of water.

My other tank, between the salt creep and the skimming, will lose about a point or two per month. Easily fixed with an extra cup of salt in my makeup water though.

[Jaws]

Hey guys. Is the venturi mod only recommended for recirculating skimmers or would this improve on any pump that had the meshwheel mod?

Are you using this mod instead of pushing air with an air pump?

Where's the best place to buy the black screw fitting and the venturi nipple from?

Is the PVC in that picture just to show you how the mod works or do you attach that to the pump intake somehow? (probably a stupid question but just want to make sure)

Also I didn't see an answer from anyone if you think a dremel could be used to cut the needles of the needle wheel or if a blade would work better.

Sorry for all the questions. Thanks.

[Delphinus]

Depends on the impeller I think, in my case the blade worked fine. If it's stiffer/stronger plastic then maybe a dremel.

The pictured venturi is intended as a replacement of the "stock" venturi .. (yes it would go onto the pump intake :) ) I'm sure it's an improvement whether the skimmer is recirc or not .. the idea here is just to get more air into the skimmer.

I could be mistaken, but I get the impression that it's only the larger skimmer folks who are using an airpump to drive the air injection.

[Jaws]

So I finished the meshwheel mod about an hour ago on my Euro Reef CS8-3+, and everything went really well. This skimmer has two sedra 5000 pumps and is pretty much the same as the RS 250. There's definitely more bubbles except now it overflows. I've got the gate valve dialed all the way down too. Before, I tried to adjust the skimmer so the water line was just below the collection cup. Now it's right at the top of the collection cup just below where it overflows. Before I cleaned the collection cup neck the skimmer was producing skimmate but it was very wet. After I cleaned the collection cup the skimmer now just overflows clear water. There's still tons of bubbles in the neck but it's only producing clear water, no skimmate. Any ideas what I can do to help this?

[Delphinus]

I think it will get better as it settles in but you might want to think about slowing the feed pump maybe.

That's awesome you get such results, I didn't get anywhere near that kind of "my cup is overflowing like crazy" type results and I thought it was maybe because of the Sedra .. so you just proved that theory wrong.

Can you snap a picture of the pumps? I'd like to see how they sit on the skimmer itself, maybe I can change how I have mine and get some more improvement that way.

[Jaws]

I think it will get better as it settles in but you might want to think about slowing the feed pump maybe.

Can you snap a picture of the pumps? I'd like to see how they sit on the skimmer itself, maybe I can change how I have mine and get some more improvement that way.


It's not a recirlution skimmer so there are no feed pumps other than the actual pumps I did the mod to. I've been running one pump at a time for 8 hours each to try and help break them in. With only one pump turned on it sure generates a lot of foam at the top after a while but because there's only one pump on it's not enough to push the foam up the neck so it can overflow in to the collection cup. As soon as I turn the second pump on the water level goes right up to the top of the neck again and overflows wet, large bubbles in to the collection cup filling it up pretty quick. The bubbles overflowing are large because there isn't enough height to form a foam. I've also noticed quite a increase in turbulence in the skimmer including the neck and not all the bubbles are really fine. There are some bubbles the size of a tic tac hovering around in the neck too. I've also adjusted my auto-topoff so the water level in the sump drops which has always lowered the water level in the skimmer too. I'll see if that helps.

The pumps sit horizontally just like in this picture:

http://www.jlaquatics.com/phpstore/store_pages/details/skimmers.php?product_ID=ps-errs250

[Delphinus]

Huh - go figure - I had figured that all multiple pump skimmer designs were recirculation style. I.e, the pump draws water from the skimmer body and the water feed to the skimmer itself is independent of the needlewheel (meshwheel now) pumps.

I had to mod my ASM to be recirculation, basically all I did was drill a new 1.75" hole (the 1" uniseal requires a 1.75" hole same as for a 1" bulkhead) and hooked the pump in that way. For the last year I've been feeding the skimmer via a T off the overflows, now I'm feeding with a maxijet 600 (after trying a maxijet 1200 for the last week). I read on asmskimmer.com/octopusskimmer.com that for a recirc skimmer you want a feed pump about 1.5 times your tank volume (but I'm not sure if that number is just a WAG on their part - I don't know if there are any metrics applied to generate that factor value of 1.5).

Seems to me you might need to think about modding the skimmer itself. The problem is that the pumps are just pushing too much volume of the air/water mixture for the exit pipe to carry out fast enough. You could start by trying to raise the skimmer so that there is a larger height differential, but it sounds to me if you're racing water through the skimmer that it doesn't have a lot of contact time. So going towards a recirc mod on your skimmer might be something to look at.

I'm not sure what I'd do. Bear in mind this is all black magic to me, so don't just follow MY advice because I'm clueless!! :lol:

[Chin_Lee]

jason
try to control the amount of air entering the venturi with a small valve and it should decrease the bubble level. as the pump breaks in more, increase the air flow to raise the bubble level.

[Jaws]

It's actually already started to settle down and I got 2" of stuff in the first 24 hours. It's definitely not as dark as the old stuff but it used to take a week to make what the mod has done in 24 hours. So far I'm happy and look forward to seeing the long term effects of this. The water line is still almost right to the top but the skimmate is thicker and darker now than the wet bubbles that it started pumping out first.

[Delphinus]

It's definitely not as dark as the old stuff but it used to take a week to make what the mod has done in 24 hours.

This is exactly my results - in fact it can pull out more in 24 hours than it used to make in a week. But the skimmate is definitely lighter. I used to pull out "Coca-cola black" skimmate, now it's more like "green tea".

But I wonder if it's not unreasonable to expect a lighter skimmate than before, if you're pulling it out faster maybe there's less DOC to pull out?

Because that my airflow hasn't increased and it doesn't appear to be a more voluminous (is that a word?) foam (like what others are claiming on RC), I'm reluctant to try lowering my water level (by opening the gate valve) too much because I'm afraid it will hit a threshold and basically stop producing skimmate. I'm still planning on modding the venturi and maybe the volute to see if I can pull the air volume #'s up a tiny bit.

[Jaws]

For me I think the color and thickness of the skimmate has to do with the water level in my skimmer. When I only had one pump running at one time and the water level in the skimmer would fill the reaction chamber, there was a nice thick foam that formed on the top. The fact that the color is weaker only makes me think that given a longer skimmer neck the foam would be thicker but that still doesn't mean that it's not pulling out the same amount of crud with wetter foam. It just overflows sooner and doesn't have a chance to form that thick foam. I can't see this being a downfall but I could be wrong.

[Jaws]

Well, it's been four days and the collection cup is full of dark skimmate. I was expecting the skimmate to be clearer but it's still pretty dark. Not quite as dark as before but almost. I'm totally impressed. I'd recommend this mod to anyone.

[Skimmerking]

Well I have a Recirculating euroreef 250 that I'm going to do tha mod once Tony sends me the stuff. I have 2 pumps on mine :biggrin: .

here is a picture of my skimmer that i will mod again :mrgreen:


http://i38.photobucket.com/albums/e122/asmodeus338/235%20Gal%20REEF/Euro%20Reef%20CS%20250%20%20mod%20to%20RC/finalpic.jpg

[Doug]

Well I have a Recirculating euroreef 250 that I'm going to do tha mod once Tony sends me the stuff. I have 2 pumps on mine :biggrin: .

here is a picture of my skimmer that i will mod again :mrgreen:


What the heck ya doing to that skimmer now. :lol:

[crystalz]

this is looking like a pretty catchy mod... heres a little twist to it. I have a CSS 65 and the ASM obviously has a much superior needle wheel. I'm just wondering if it may be possible to improve on this model by using the same mod?

[Delphinus]

I'm so convinced of this mod, I think *any* needlewheel based skimmer would benefit from the mod.

I even think that this could breathe new life into older venturi model skimmers with a few extra mods. For example, those skimmers usually had the venturi between the pump and the skimmer (and just had a regular old impeller in the pump). Change it around so that the venturi is on the pump intake instead of the output, mod the impeller, and see what happens. In fact I regret unloading all my old venturi skimmers now because I really want to see what kind of difference it could make.

In fact, I'm now so convinced of this mod, that I'm considering unloading my two beckett skimmers. And I *love* my PM Bullet-1 skimmer, it has been an absolute workhorse for the last 5 years for me, it's been an incredible skimmer so to say I'm ready to consider selling it and going to all meshwheels should say how much I believe in this mod now. :) I feel silly for waiting so long to try it.

[christyf5]

this is looking like a pretty catchy mod... heres a little twist to it. I have a CSS 65 and the ASM obviously has a much superior needle wheel. I'm just wondering if it may be possible to improve on this model by using the same mod?

People have been doing this mod on every skimmer going I think :razz: I'm sure there is a thread on RC for the CSS. Darned search function is screwy though.

Here is what I found:

http://www.reefcentral.com/forums/showthread.php?threadid=1006566

[Delphinus]

Quick update, I finally found the skimmer not producing any bubbles yesterday and couldn't get it to restart. Usually if I had to switch the pump off I just had to blow into the airline to get it to restart but not this time.

I took apart the pump and the fishing line had worked its way loose. Soo .. I'm thinking, fishing line isn't a good way to attach the mesh.

I reattached the 3 layers using 2 zap straps and trimmed the mesh a little. Restarts on its own now, so that's good. :)

Since I had it apart anyhow, I decided to drill out the venturi a little. Wow, just one drillbit size up from the one that fit into the hole already and I can tell it's pulling way more air. Unfortunately I lent out my airmeter so I can't tell how much more but I wish I had done this weeks ago, it looks like it's skimming even better now.

[crystalz]

(in regards to the css mod) As soon as I seen the link I went and cut some line off my fishing rod. I havve to say that this worked AWESOME! My skimmer is producing the most and finest micro bubbles I've ever see it make. What a HUGE difference. Thanks for the info. I found you need a good knot to keep it on there. Once I tied my knot I put a tiny little dot of crazy glue on it for extra insurance. It's holding so far with no problems.

[Skimmerking]

I wouldnt use the fishing line go wit hthe zap ties...

[Delphinus]

I like the idea of krazy glue to hold the knot down. I really have a hard time with knots on fishing line and seem that even little miniature versions of knots that are supposed to not slip (figure 8's, bowlines, etc.) still slip because the line is so slippery. I'll try the krazy glue trick next time!!

What's weird, I don't know if it's because of the zap straps or the air intake hole is larger, but, the pump has a different sound to it now. It has a weird sort of "electrical buzz" sort of sound and if I block the airline it gets REALLY loud. Seems to be working just fine though, so I'm not too worried about it, but did just notice that the "operating noise" has gone up a little.

[cprowler]

I used gutter guard and reaming out the Venturi with a drill bit. I don't have a air flow metre to test the intake but I can see that it's working better producing skimmate immediately. I also used zap straps and it's been holding and starting fine.



http://zld.ca/reef/Mesh-mod-1.jpg

http://zld.ca/reef/Mesh-mod-2.jpg

[Jaws]

Since I've done the mod, it worked great for a week or two and now it's overflowing again. I'm not sure what else to do.

[Delphinus]

I think I'd be looking at modifying the pumps so that the intakes draw water from the skimmer, then use a separate pump or powerhead to feed the skimmer. The recommendation for recirc pumps seems to be 1.5 times the tank volume per hour. It has the benefit of increasing dwell time, for whatever that's worth, but it also gives you the benefit of controlling your level independent of your foam production.

If you're running this insump, see if you can find some uniseals, then all you'd have to do is jam some pipe through the uniseals, hook them up the pump intake, and then you're done. If you're running the skimmer externally, you'll need to do something like using a bushing for the next size up down to the size of your pump intake, use weldon to attach the bushing to the skimmer body, and then pump into that.

It should be pretty do-able. The downside is you'll need to take your skimmer offline for about a day to do it.

[fkshiu]

Did it this weekend (thanks to Delphinus for the Enkamat).

Works like a charm. There are definitely more and smaller bubbles and almost 2x the amount of skimmate that I normally have after 4 days. Not bad for a half hour's work involving a few pieces of mesh and a couple zip ties.

I was also fortunate enough not to have the skimmer overflow as others have experienced.

Note also that adding the mesh was all I did. I did not do anything to the venturi or even ream out the intake (my drill is currently down for the count). And I simply have a ER 6-2 w/a Sedra 5000 sitting in my sump. The only previous mod was adding a gate valve (i.e. no recirc, gravity feed, etc).

[christyf5]

I also did this mod on the weekend. I used 3 layers of enkamat and zap strapped it onto the impeller sans needles. I had some troubles restarting the pump after that and had to trim some of the enkamat down on the sides and top. Eventually it cranked up and I got even more bubbles than the previous mod I had done (which consisted of me putting a different type of enkamat on over the needles). Foam was nice and milky white but even with the gate valve fully open the foam was too high into the riser tube for my liking. I chopped about an inch and a half off of the gate valve pipe to lower it and the level in the riser was perfect. The skimmer was performing well when I left it but I'm not sure how much more skimmate it has made compared to before.

[fishface]

well, my experiment with this provided to be unfruitful and about a waste of at least an hour of my precious time:). i tried a combination of christy's and bill's attempts, by that i mean i used gutterguard cause i didn't have the enkamat and i just put the layers over top of the needles cause i was paranoid and didn't want to potentially kill an impeller.

end result was that the skimmer worked fine this way but there was in no way any improvement in performance or bubble production. just one persons experience here...i guess sometimes ya just have to go for it huh?

[Delphinus]

Yeah, I think you really need to do the dirty deed of cutting off the impellers.

If it helps, I resisted this for a long time too, finally decided to go for it, and .. I don't regret it one bit. It's by far the best thing you can do to your skimmer to "make it better."

I can send you some Enkamat if you want .. I have a roll of the friggin' stuff and I've sent pieces in the mail several times now. PM me if you want to go that route..

[tang daddy]

Yeah, I think you really need to do the dirty deed of cutting off the impellers.

If it helps, I resisted this for a long time too, finally decided to go for it, and .. I don't regret it one bit. It's by far the best thing you can do to your skimmer to "make it better."

I can send you some Enkamat if you want .. I have a roll of the friggin' stuff and I've sent pieces in the mail several times now. PM me if you want to go that route..

Tony, pls send me some enkamat if it's possible would like to see the difference between enkamat and gutterguard thx oh pls check pm.

[fishface]

so the results are in......i've just done the mod to a sedra 9000 and so far i can see that there's smaller bubbles but not anymore foam is being produced than what i was getting before. i guess time will tell with the resulting quality and amount of skimmate. we shall see...

ps. thanks again for the enkamat Tony.

[Delphinus]

Yeah, I found that I didn't reallt get "more overall air" into the skimmer but the bubbles were visibly smaller than before and I got a much better, and more consistent, skimmate production. Hope you find over a couple of days that it is better than "pre-mod". :)

[fishface]

well, after several days of trying this mod i have to say that overall i went back to gutterguard due to unreliable and very noisy starts. perhaps i did something wrong with the enkamat, but after going to gutterguard i seem to be getting pretty much the same results as what the impeller was before the mod. but like i mentioned, quieter and much more reliable restarts... oh well, can't say i never tried:mrgreen: .

[fishface]

update: i wanted to try the enkemat again so i gave it a shot today and i have to say, i gotta eat my words. i remounted this stuff and trimmed the edges more and i AM getting larger amounts of and smaller bubble production. i also noted that taking the valve off of the venturi line increased bubble by perhaps 10-15% as well. thanks again Tony, glad i revisited this mod!

[Chaloupa]

Old thread but very very useful.....I am going to mod my 2 Euroreefs and am sooo glad Christy pointed me to this thread.

Now to find some Enkamat!!!

[Tangman]

Hey if you find some Enkamat , let us know where you got it as i would like to try this mod aswell

[Delphinus]

I've pretty much run out of the stuff, I have a few little scraps of it left and that's about it. Otherwise I'd say I'd send you guys some, sorry ..

Here are some suggestions though, hope this helps!
If you want about 2 yards so you can set up other people with some, it's about $30:
http://www.aquaticeco.com/subcategories/3107/Enkamat-Nylon/enkamat/0
Make sure to contact them though to ask for USPS instead of the default UPS otherwise you'll get nailed with a brokerage fee.

Other options:
http://www.aquaticeco.com/subcategories/3107/Enkamat-Nylon/enkamat/0
$5 for a 12x12 piece, minus the shipping of course, but at least you could buy something else at the same time..

And sometimes it shows up on ebay:
http://shop.ebay.com/?_from=R40&_trksid=m38.l1313&_nkw=enkamat&_sacat=See-All-Categories

[Pescador]

I found this place as well, I'm going to give it a shot on a couple Sedra 5000's.
http://www.meshmod.net/