There are two venturis...
http://www.sgreefclub.com/forum/index.php?showtopic=51002&st=0
http://www.zeovit.com/forums/showthread.php?t=8204
From the second one, the venturi inlet is listed as 15mm.
I made my venturi 5/8" ID, which is the diameter of 1/2" PVC, which is 15.875mm. Then I have the adjustable ball valve further up the line so I can match the restriction of a 13mm intake if I need to. I have tried this, and no greater intake has happened. FWIW, I played with a couple venturis (ball valve only venturis, a beckett, etc) and they came up the same. I shouldnt have to tap the threaded neck of the intake, I know that. If you look at how the venturi works, where you have the air inlet is not critical. Really, all a venturi is on a pump like this is a restrictor.... thats it. I can actually take out the 1/2" restriction part, lengthen the airline into the pump's intake, and use the ball valve to get the exact same results. A venturi on an asperating skimmer is not very technical... it does not act as a flow eductor like on a venturi that goes on an outlet of a pump. I just wanted to mimic the ATI version for kicks so the ball valve would allow me the most fine tuning ability. There is also that other version that shows that this is not important if you look at the first link. IME, the venturi is not flawed. Being that every version I have of it is giving me the exact same results, Im thinking its the pump. The recirc mounting doesnt change anything either. For those who read all my details, I am testing the pump by dropping it in the tank first as well... so back pressure due to depth doesnt change much. My back pressure should be the same, if not better than a bubblemaster actually. The pump is mounted 20" from the top of the skimmer, 10" below the waterline. This is about the same, if not better, than an ATI bubblemaster, which places the pump at the bottom of a 20-22" tall skimmer... non-recirculating. From the details, you may have read that I can actually get the pump to 'pulse' (it actually jumps up to 40-50 scfh when it does this) if I dont restrict the air intake some. So the venturi is plenty effective & free-flowing.
Oh, and why bother with a Laguna? Well, a Laguna 2400 does 120scfh, or 57lpm... at almost 3' of depth. These ATIs will choke on more than 2' of depth, if that. And they will do it for less than 90 watts.
But on the PSK here... what are you guys seeing as far as the mesh goes? is it too tight? Too thin (3/8"?), or too narrow? Its got to be something along these lines. It seems like the zip-ties are rubbing on the backside of the impeller well in my case because the plastic on the pump looks like it (I have no basis for comparison, but this might be why my pumps seems to hum a bit more than I expected). Even though I dont see ATI's being any smaller, perhaps because my holes are towards the center more...???
Just curious, can I get just the impellers from anyone? Smjtkj or Jayson? I would like to buy a couple as backup for just water pumps if nothing else.?
i want to show you that it is possible to pick more it's just the way of the mod and i did it quick after the last post i made . i am sure the performance even can be better but need to work on it ....
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