By Bob Goemans
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Sentry Dosing Pump

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A product review by Bob Goemans

Product Review - Sentry Dosing Pump

When Stan Furman, president of sent his 'Sentry' model dosing pump for review, it actually arrived about two years after we first met and began discussing his products. Even though we chatted numerous times about the capabilities of his various dosers, he always wanted to add another feature so as to be sure every possible aspect an aquarist might want would be available. He now feels sure he has accomplished that goal!

As with any aquarium equipment purchase, quality and dependability issues are all important. In fact, I took these issues much further than I would normally because there were rumors these dosing pumps were nothing more than used hospital equipment, which are of course extremely accurate and reliable dosing devices. First, let me say those rumors are untrue, however, some of the solid-state electronics is obtained from existing medical equipment in order to both lower production costs as well as to provide the highest quality equipment possible. Without this cost advantage, the price of these dosing pumps would be beyond that of most aquarists. And it should be noted that the electronic circuitry is upgraded to meet aquarists' specific needs, maintaining accuracy and dependability. This is then installed in a new, modified housing designed for aquarium use. Therefore, quality, accuracy and dependability of these dosers is unapproachable.

With those issues resolved, probably operational noise level would be another aspect to consider. Of course, no one wants a noisy dosing pump, and these units are practically noiseless. In fact, there is only one moving part! If you do hear anything, it's barely audible when the pump is operating. And that's a nice feature for aquarists that may have an aquarium in their bedroom!

As for dosing accuracy, these dosing pumps can supply as little as a few drops per day! At that rate, those drops would probably evaporate before they reached the aquarium! So the dosing rate can be as little as you desire, or up to about five gallons per day. And that should meet the need of most aquarists.

A large bright flat panel digital LED display having touch-sensitive moisture resistant switches is another feature. It only took me five minutes from the time I took it out of the box to get it up and running.

The distance it will draw water up from and then dispense to is another capability that should be known before buying a doser. All the models from are capable of drawing water from about three feet below the pump and dispensing it to at least fifteen feet above. So placement of the pump should be well within reach of all aquarist logistic needs. And I should note these peristaltic pumps experience no siphoning effect when not operating, which is an extremely important aspect. And this new Sentry model is powered by a 12VDC powered adapter, and contains an internal nickel cadmium battery that will keep the pump "running" for about one hour should there be a power failure. And since pump operation cycles as needed to pump the set dosage rate per hour, the longevity of the units overall battery power supply is far longer than one hour. And even if without any power, all settings remain locked in for at least 24 hours.

The above are important basics, and below are options that make these dosers even more functional.

First, and something that really interested me because I use a two-part pH and alkalinity buffer solution for my small 60 gallon reef tank, was that all dosers are capable of delivering an equal amount of each solution as needed. In other words, whatever amount the aquarium needs per day of each solution can be delivered using an optional inexpensive two-channel tubing set where one tube is placed in Part A and the other tube is placed in Part B. When the pump turns on at the user's digitally-selected rate, equal amount of Part A&B will be dispensed. That way, each is separately delivered to the aquarium, which simply does away with this morning chore in my everyday life! What a great optional feature for those of us using these type solutions!

Another optional feature is a 'Float Switch.' When plugged into the unit with the float placed in the aquarium or sump, should the water level ever rise too far for some reason, the float stops the motor while the pump maintains it's lit display and all user settings, preventing any further additions until the level drops.

The 'Darkness Sensor,' included with each Sentry, is another interesting option. For those reef aquarists that like to dose Kalkwasser during evening hours, the Darkness Sensor will 'turn-on' the dosing pump so it will only dispense during the time the sensor is in the dark. That's a quite novel approach to an old situation where the aquarist had to use a timer to begin and end delivery of Kalkwasser.

And if there's a need to control the doser and its float switch and/or light sensor through an A/C powered pH controller or computerized monitoring system, there's also an optional A/C Controller. So usage possibilities for these dosers are practically endless.

There's also a model with a built-in timer having 8 different on-off settings for each day of the week. So there are numerous different scheduling possibilities for makeup water, Kalkwasser, trace elements, etc. And these dosers are all quite small, about 6" long, 7" high and 5" deep, which is about the size of two playing cards side-by-side!

Were there any shortcomings? Good question and in all fairness only very minor ones. One was with the instruction manual as it needed to be revised and updated with the latest information on all the different models and newly available optional equipment. Also, none of the dosing pumps had a nameplate noting their model name. The only way to tell them apart was by the capabilities that existed within them. Nor was there an electrical data plate noting electrical usage, which by the way is only 5 watts when running. All are currently being corrected as I write this review.

All-in-all, these are high quality extremely accurate and reliable dosers guaranteed for one full year. They should meet all your aquarium system dosing needs. For specifics on all the different models, visit their website at

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