Skimmer and Venturis 

©   1996, Allen Rogers 
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I have not been very happy with most of the commercially available venturi skimmers. They just don't produce the bubble volume and bubble size required for efficient skimming. In order to create the quantity and quality of bubbles needed, you need to use a good venturi valve. IMO, the Mazzei valve is the only one currently available to handle this task. 

Most commercially available units don't use this valve although some are now becoming available. In addition to this, they require a very high pressure pump in order to produce the quantity and quality of bubbles. This leads to the next problem with most commercially produced venturi skimmers. When using a Mazzei valve and a good high pressure pump, an enormous amount of air will be drawn into the skimmer column. 

The neck in these skimmers needs to be wider and longer than most commercially manufactured skimmers. Otherwise you just collect gallons and gallons of wet foam with very little pollutant in it. Sure, if you tank has a lot of dissolved organics most of the commercially available units will seem to work fine, but when trying get those levels even lower the same unit will essentially shut down. They simply can't remove lower concentrations of organics. 

I have used a popular venturi skimmer using an even larger pump than was recommended by the manufacturer. It still didn't produce the bubble size or volume to be efficient. After about a month there were almost no bubbles in the skimmer at all. I have heard good reviews about the ETS but have not seen it in operation. 

This may or may not be a lot of marketing hype. I would sure want to see it in operation before I pay the bill on that unit. Until someone can convince me otherwise (show me don't tell me) I would stick with a counter current style skimmer that uses a pump to direct a large volume of water through the skimmer column and a limewood air stone to generate the bubbles. Although the initial price tag and maintenance is a little more, it is well worth it in the long run. 

Contributed by Allen Rogers . Click to send him email. Thanks. 
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