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:

drill the venturi
 

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/o...43imagdne1.jpg

no pic there Chin...:mrgreen:

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

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.

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.

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.

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?

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.

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/s..._ID=ps-errs250