Custom machined venturis for PSK-2500

As part of the upcoming launch of the CS1 Cone Skimmer Kit, we are releasing our newly developed venturi and modified volute for the Sicce PSK-2500 pinwheel pump, which is an optional component of the kit. This custom venturi was designed by us in-house, optimized for the cone body that comes with the kit, and made of polished acrylic. It’s interesting to watch the interaction of the air and water as it mixes upon contact with the pinwheel. Airflow and waterflow details coming soon.

Custom Swabbies ready to ship

For those of you who got in on the initial run of custom sized Swabbies, you’ll be happy to know they shipped yesterday!  Pictured are some of this week’s shipment.  Thanks for your support and may your skimmers be forever clean and productive!

For the inaugural post of our “Captain’s Blog”, I am going to detail the construction of a large ozone reactor that Dan and I built for my aquaculture greenhouse.  With a total system capacity of about 5000 gallons, I needed something more than simply bubbling ozone into a skimmer.  There are very few quality ozone reactors on the market, and none at the scale I need and a price within reach.  I also wanted to use a design that uses a misting nozzle to spray the seawater into ozonated air in order to maximize reaction surface area, minimizing the total amount of ozone needed.  This meant as large a chamber as realistically possible, with as little water as possible.  Dan and I did some calculations based on the equations in P.R. Escobal’s Aquatic Systems Engineering.  In order to ozonate 99.99% of the water each day (9.2 purity coefficient), we need to push about 1500gph through the reactor and still have a 30 second dwell time.  Since we had some 14″ diameter tubing handy, this meant keeping about 20″ of water in the bottom, or about 13 gallons.

In order to make the body assembly relatively simple, I decided to use off-the-shelf flange fittings from an industrial plastic supplier:

Connecting the 14" flanges

These fittings are only 3/16″ wall thickness, not strong enough to hold back the desired working pressure of 3-4 PSI.  Next step was cutting a matched flange and lid from 3/4″ acrylic, and bonding that to the PVC flange:

Gluing the 3/4" acrylic flange to the PVC body

Getting the body glued together was the hardest part of the entire build.  I wanted to get it bonded cleanly with minimal drips and bubbles, and never having done this size lid in a PVC to acrylic joint before made the process interesting.  After that, doing the simple plumbing on the lid was relatively straightforward.  I used a 2″ input pipe which reduces into the 3/4″ spray nozzle, a Bete 316SS TF32.  The output is simply a bulkhead which reduces into a run of 1/2″ PVC pipe back to the carbon postfilter.  This narrow effluent line creates the necessary backpressure without needing an expensive ozone-safe gate valve.  I can vary the working pressure in the reactor by controlling water input at the inbound gate valve.  The tiny 1/4″ tubing is the pressure relief system, which regulates the water level inside the reactor by allowing a small amount of air to burp out of the reactor as the air pump forces ozone into the chamber.  Finally, since this is an experimental unit, a nice 316SS pressure gauge lets me know what’s going on inside with the air.

Lid of ozone reactor

I opted to use 316SS bolts to secure the lid in case of accidental pressure increase.

Pumping in ozonated air is accomplished by means of a vacuum pump with all stainless and teflon components.  It draws ozonated air from a Clearwater Tech CD10/AD ozone generator.  This model provides approximately 1.3g/hr and has a built-in regenerative air dryer, so I don’t have to mess around with cooking beads in the oven every few days.

Here is a photo sort of showing the spray nozzle in action.  It makes water droplets all over the inside of the lid very quickly so it was hard to get a good shot.

Lid showing the spray nozzle in action

So far, this reactor has been running for a couple of months at approximately 30% of peak ozone output.  Water clarity is perfect; a “yellow bucket test” gives water that is visually indistinguishable from newly mixed seawater.  I have noticed a general improvement in coral polyp extension now that the ORP level stays in the 300’s all the time.

Dan and I are currently working on scaling this design down to a 4″ diameter reactor which will be available in kit or prebuilt form and suitable for tanks 75-200 gallons.  A 6″ diameter body designed for tanks in the 200-500 gallon range is not far behind.  The beauty of these reactors is their simplicty; no moving parts to fail, and we’ve eliminated the costly components like the pressure gauge and SS spray nozzle in order to keep them affordable.