Hello to you salt water enthusiasts

As a result of a posting on Reef Central web site, this page was added on March 5, 2003.

Perhaps you know the benefits of eductors in your tank -- Solution eductors mounted on the discharge pump piping will increase the flow agitation provided by your current pump by 2 to 3 times while your pump draws less current.

Penductors are mounted on the discharge side of the pump and must be submerged to move (educt) additional liquid - once you get close to the "best efficiency" point of 10 PSI (or 23 feet if looking a pump performance curve) you can pump about 7 GPM and educt about 28 GPM to produce a movement of 35 GPM per eductor.  Penductors can be used with pressures as low as 3.5 PSI (8 feet) with reduced flows. 

The flows above are using a Penductor.  This eductor uses an orifice (round hole) of .3" diameter.  This restriction causes a pressure drop of the solution - the energy is transferred into solution velocity.  This velocity is transferred back into pressure that drags (educts) additional solution through the bell shaped nozzle of the eductor.  (If you followed all of that good for you - if not - think of it as magic.)

  for 2005.  Penductors are now available in a black color polypropylene material with 3/4" male or female threads.  Please specify as BLACK to avoid the standard blue color.  1" is not available in black until October 2005. 
 for 2005.  Penductors are now available with .375 orifice for higher flow rates.  Same short profile as the standard .30" orifice.  Only 3 7/8" long.

Now, the question - how many eductors do I use?

Answer - depends upon your pump - The bigger the pump, the more eductors you can use.

Now my question - If  your pump came with a performance curve, look at the flow in "gallons per minute" when the pump is producing 23 feet (same as 10 PSI) and divide this number by 7 - (the ideal flow rate is 7 GPM at 10 PSI) - THIS IS THE MINIMUM NUMBER OF EDUCTORS .  We have however experienced very good results with lower pressures.

For you Iwaki guys, I have the (top secret) performance curves and will do the math you.  Also listed are the horsepower of each pump.  (HP x .75 = kW) 

MD (or WMD) 6, 20, 20RZT - Give this pump to your kids - not big enough.

30RZT or 30 RXT - (1/16 HP) - you will notice improvement with one eductor however you are still on the small side.  

40 RXT - (1/12 HP) - maybe two - however you are on the low pressure side but will see solution movement improvement. 

55RT -  ( 1/9 HP) - definitely you would really charge one - you might what to distribute the wealth and use two.

70RT - (1/4 HP) - you will drive two or three eductors. v

70RZ - (1/4 HP) - use two - the pump runs out of flow beyond 10 GPM - This however is a really good pump to utilize the eductor principle because it produces high pressure at low flow. With two .30" orifice eductors, the pump will go from moving 11 GPM to 50 GPM.

100RT - (1/3 HP) definitely three will get very excited - four would probably be best to prevent too much in one area.  

For the above pumps I would suggest installing a ball valve between the pump and the eductor (probably just one if you are using two or more) just as a control device to maybe slow things down if the eductors / Penductors work too good.

What if I don't have "a pressure rated pump" or 10 PSI - will they still work?   Yes, however the fan angle will decrease and the extra solution educted will also decrease but amazing results will still be realized. Low pressure chart.  (All pumps produce pressure otherwise they wouldn't be able to move liquid through the pipe - let's call them a low pressure pump, OK?)

What kind of results should I expect from Penductors ?  You should normally see an increase of solution movement of 2 to 3 times compared to open flow return pipe outlets.  This does however assume a flow rate of 4 1/2 to 10 GPM for each Penductor.  Knowing the pressure and using the flow charts will assure these results. 

What about all of the other devices on the discharge of my pump - filter, strainers, Sea Swirls?  The water will need to be restricted through these other devices to allow pressure for the eductors.  Use control (ball) valves to provide the additional backpressure that will be required to provide adequate pressure for the eductors.  Using Penductors on return lines with filters and strainers is OK but I would avoid using on the discharge of a Sea Swirl.  (Sea Swirl is not designed to be used with a down stream pressure device such as a Penductor.)

A word to the wise:

Almost all pumps are also rated in maximum GPH.  This flow will only be achieved with near zero pressure.  Do Not use this number to determine the amount of flow that you will push through the eductor.

Question - What eductors do I buy - The material of choice is polypropylene. 3/4" and 1" threads are now available in a black color.  All Penductors are standard with the .3" orifice so it is your choice as connection size between

PE 3/4 FB - 3/4" female threads 
PE 3/4 MB - 3/4" male threads
PE 1 MB - 1" male threads - (now available in black)

All are the same price.  Please specify if .375 orifice or black color is desired.

How much do they cost - $ 29.00 each  - free shipping to US or Ca for four or more.  Quantity discounts are available for 10 or more for clubs or retail locations.

Can I make my own?  Home made version

How do I order - e-mail your order (or fax) to KTH Sales, Inc and include your shipping address and daytime phone number.  We will give you a phone call to confirm, advise shipping time (usually the same day), and get your Visa or MasterCard card number.  Or you can call us at 800-235-3604 or 219-736-0060.  Shipping is via  UPS - $ 1.50 plus actual UPS charges - UPS collect is OK if you provide us with your account number.

Penductors are now available at retail locations:

My Reef Creations - Lawrenceville, GA 30045  - Phone: (678) 407-3773 -  www.myreefcreations.com

All Seas Marine - Torrance, CA - Phone:  (310) 532-7769 - www.allseasmarineinc.com

Custom Aquatics - Oceanside, CA - Phone: (760) 277-6128 or info@customaquatic.com

Dirk’s (Griffin) - Red Wing MN - Phone: (651) 388-7319 or  Reefgrip@hotmail.com

Premium Aquatics - Indianapolis, IN - Phone: (317) 895-9005 or  sales@premiumaquatics.com

KTH Home Page     e-mail: Ken@KTHSales.com    

phone 800-235-3604   Fax: 219-769-0263

 Revised 4-21-2006.