By Bob Goemans
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HSA Protein Skimmer

Manufactured by: Marine Technical Concepts

A product review by Bob Goemans

HSA Protein Skimmer:

(Written 2003)

This month's article covers the Marine Technical Concept High Speed Aeration(HSA) Protein Skimmer. Until recently, the world championship for efficiency probably belonged to downdraft type skimmers. That may no longer be true! First, let me be right up front and say readers of this column over the past twelve years have grown accustom to seeing factual product reviews. Not reviews from paid help, but from someone who has been in the hobby for many years (now over fifty years) and has never been an employee of any aquarium product company. These reviews are based on close scrutiny of either in-depth reader feedback and/or personal experience with the product(s). If the product is leading edge and deserves your attention, yet may still have some small discrepancies, I'll voice them as I see fit and you'll see it here in print. If it's a product that is poorly designed, or has no positive value for the organisms, and/or valuable processes in our aquariums, the product will not appear in this column. It's that simple.

As for the Marine Technical Concept HSA Protein Skimmer, it deserves your attention, even though it may be too efficient for some applications. I'll explain more on that thought towards the end of this article. There are three models: HSA 500, 1000, and 2000. These are large, column-shaped skimmers, with the smallest standing 28 inches and the single column HSA 1000 and double column 2000 model standing 46 inches high. This means they will probably not fit in the space under your stand-mounted aquarium and that a remote, yet convenient location near the aquarium/sump will be required.

They consist of a Base Unit, which is an acrylic box with a footprint of 10 x 10 inches and stands 7 inches high. A supplied 1.5 inch gate valve connects to the side of the Base Unit and controls exiting water, which in turn controls water height in the skimmer column.

The HSA 500 has a one-piece Reaction Cylinder which attaches to the Base Unit. The 1000 & 2000 models have separate top and bottom Reaction Cylinders. The most upper portion of these Reaction Cylinders contains a Collection Cup. This fixed, that is to say, non-removal Collection Cup is equipped with a drain that connects to separate Waste Collector. The removable "top" of the Collection Cup has a small acrylic chamber on its top surface that houses the units Aeration Nozzle Assembly. An internal two-piece PVC Foam Delivery Tube connects to the Aeration Nozzle Assembly and directs its highly oxygenated water downward to a concave-shaped dish located at the bottom of the lower Reaction Cylinder.

Included in the price of an HSA is a separate Waste Collector. The Waste Collector is designed to automatically reduce the likelihood of a skimmer induced overflow. Marine Technical Concept recommends certain pumps for certain HSA models and their advice should be heeded. The HSA's efficiency depends upon adequate water flow and head pressure.

As for system flow, the water pump brings in water from the aquarium/sump and forces it through the top mounted Aeration Nozzle Assembly. The forced, downward flow of water through this device sucks in a 'huge' amount of air. The then highly oxygenated water flows downward through the Foam Delivery Tube and exits just above the concave dish at the base of the lower Reaction Cylinder. The exiting water bounces-off this concave surface and is forced outward and upwards into the Reaction Cylinder(s). The Aeration Nozzle Assembly produces extremely fine bubbles, and results in an excellent quality, dry foam at the top of the unit. Column water drains into the Base Unit where it flows through the gate valve and via gravity back to the aquarium/sump.

The amount of foam produced is in relation to the amount of air that enters through an adjustable air intake fitting located on the small acrylic chamber that houses the units Aeration Nozzle. In fact, these HSA's can draw so much air, that an audible sucking sound can be heard when the valve is wide-open!

When properly installed, the amount of foam produced is almost beyond belief! I doubt whether there is anything similar in size and uses the same, small amount of electrical energy that can match it.

Yet, as good as it can be, there are areas in design, set up, and operation that must either be lived with so to speak, and/or closely adhered to. I speak from experience on this subject as I set up the product review HSA 1000 on a test bench in front of my aquarium for three weeks while checking it out. In fact, pictures of it were displayed during my speaking engagement in New York earlier this year. I can still hear my wife's "statements" ringing in my ears on how messy my office looked with what she called a "big contraption" blocking the view of my 125 gallon reef system.

As for design, set up, and operation factors of interest, the following "learning curve" circumstances are presented for your enlightenment:

* Even though my aquarium system had a very good venturi protein skimmer in operation before hooking up the HSA skimmer, I was amazed by the consistency of the thick, dark foam the HSA was removing. I have a large Yellow Leather, Sarcophyton elegans, that had almost completed dividing itself into two separate organisms. For the first three days the HSA skimmer was in operation, this 8 - 10 inch Yellow Leather remained shrunken to a 5 inch specimen. On the forth day, it again fully opened and has remained so. What this pointed out was the HSA further reduced the nutrient load and therefore the amount of green band refractance increased, as opposed to red band absorption. This was clearly sensed by this coral and it took a few days for it to adjust itself to the better change in spectrum! The point here is that HSA efficiency can be far better than other, so-called efficient skimmers. Yet, as good as the HSA is, it may be too efficient for some systems. I say some systems because those who already have excellent sps systems may not want a further draw on organic carbon and/or trace elements. Of course, if equipped with a HSA, the skimmer operation could always be limited to certain time frames. Where most hobbyists are concerned, the HSA would provide major water quality improvements as it did in my system.

* Anything that is difficult or not easy to clean, gets cleaned less often then it should. Unfortunately, I find the HSA somewhat inconvenient to clean. My old venturi skimmer took about three minutes to empty the cup, wash it clean and reinstall it. I did that every few days, as it was not equipped with a separate waste collector. With the HSA, the skimmer pump must be shutdown before attempting to remove the Collection Cup cover. If the pump is not shutdown and the Collection Cup cover is loosened, additional air would be sucked into the system and cause the water/foam column to rise and quickly overflow the Collection Cup and fill the Waste Collector. If you want to take the Collection Cup cover to a sink to clean it, the incoming water supply must be disconnected from it. There is a quality made, 90° screw-on fitting that makes this little chore very easy. After the fitting is disconnected, 10 white nylon screws must be loosened enough to allow the Collection Cup cover to be slightly rotated and lifted off. In doing so, the outlet of the Aeration Nozzle Assembly is separated from the Foam Delivery Tube. The inside of the Collection Cup and a portion of the Reaction Cylinder(s) can be reached by hand and wiped clean depending upon the length of your arm. A large, long handled bottle brush could also be used inside the Reaction Cylinder(s). The Foam Delivery Tube can also be removed and cleaned. Having it out of the way makes cleaning the inside areas of the Reaction Cylinder(s) much easier. Once the areas are clean, simply reverse this procedure and turn on the pump. Somewhat time consuming, yet nothing difficult. If you want to accomplish a little better cleaning job, the upper Cylinder with the Collection Cup can be removed from the lower cylinder or Base Unit and cleaned as needed. Fortunately, I found only removing the Collection Cup cover necessary for my needs. Anytime the Reaction Cylinders are removed, salt creep at the black ETDM material gaskets can be a nuisance for a few days after restarting the unit. I have been advised that using talcum powder or the lubrication used on ice cream machines would prevent this seepage. Something I have yet to try, but I hear it works well.

* A separate, anti-siphon Waste Collector is included with each HSA system. It's connected via a length of plastic tubing to a drain connection in the bottom of the Collection Cup. How much tubing is needed, depends on where you want to place the Collector. The top of the Waste Collector is equipped with an anti-siphon assembly that uses a ping-pong-like ball. Should the collector fill with water, the ball will float to the top of the assembly and block any further flow into the collector, thereby effectively stopping any further flow of water into or out of the skimmer. Mounted above the anti-siphon device is an activated carbon air filter. All incoming skimmer air exits though the Waste Collector air filter. The Waste Collector cover can be removed while the skimmer pump is operating so that the container can be emptied as needed. Even though the HSA skimmer could be operated without the Waste Collector, I would advise against it. A siphon effect could happen, depending upon the location of the unit, when the system automatically restarts after a power failure. To be on the safe side, always use the Waste Collector.

* Because so much air is flowed through the HSA, overall system evaporation is much greater. My daily system evaporation increased by 25 to 50%. Anyone dosing Kalkwasser would be pleased with that. Otherwise, evaporation reservoirs should be closely monitored. Another possible benefit from increased evaporation, depending upon where you live, is the temperature drop associated with the increased evaporation rate. I found my system running 1 - 2° cooler.

* As for the units written instructions, I found details surrounding the initial adjustment of column water height and air control to be somewhat lacking. However, the folks at Marine Technical Concepts are always available and willing to speak with you.

* Aquarium sump capacity is a limiting factor. If the aquarium sump is too small, a power outage will allow most of the water in the skimmer to flow back into the sump and possibly cause an overflow. This is something to be thought of before purchasing an HSA and if in doubt, discuss it with the folks at Marine Technical Concepts.

* There is a connection on top of the Collection Cup cover to connect an ozonizer. The entire unit, including the gaskets are ozone-safe. If that is something you may want to do, remember to shut off the skimmer pump before taking the small cover off the ozone connector. The additional air that would be sucked into the skimmer through this connection will immediately raise skimmer water/foam height and overflow the Collection Cup. I learned the hard way, as it was one of the tests I wanted to perform on the unit. I should add, that small amounts of ozone are highly efficient in the HSA models because of its extremely efficient air/water mixture. So efficient, that activated carbon may not be needed to flow its effluent over!

In closing, Marine Technical Concept is known for heavy duty, quality constructed products. Their customer service has always been outstanding, and in keeping with their other quality products, they are reasonably priced. If you're in the market for a "highly efficient" protein skimmer, be sure to check it out. If you can access the Web, you can see the units at

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