For decades all of our fresh and saltwater aquarium worked just fine with dumb, one speed AC water pumps so we still remember setting up our first ever controllable DC pump. We didn’t really understand what we would achieve with this Tunze Silence Controllable back in 2010 but in the intervening years we’ve really come to appreciate the ability to control water flow rates without a ball valve.
There’s three main reasons why we can’t live without controllable pumps anymore which include oversizing the pump for your tank, balancing the continuous siphon overflow with the return water, and fine tuning foam production in protein skimmers. Besides the obvious convenience of being able to adjust your return pump to your preferred flow rate, being able to purchase a larger pump than you need and then dialing it back so it’s not running at maximum speed will go a long way towards improving your return pump lifetime performance.
A larger pump running at 60-80% capacity will run much quieter, much cooler, and much gentler on its bearings increasing the lifetime of the pump and especially the impeller. The cooler running temperature of a pump that is throttled back will greatly reduce the buildup of lime and calcium deposits further reducing the wear and tear and increasing the intervals between cleaning this important component.
One other aspect of a controllable pump that has become increasingly important with various techniques for silencing the water draining down to the sump is balancing the drain with the feed water. Pretty much all discussion of Bean and continuous siphon overflows only mention adjusting the gate or diaphragm valve of the water draining down, but there’s nothing stopping us from using controllable pumps to do the same! If there’s a little too much water draining down you can just back off the pump, if there’s too little you can ramp it up a bit, and in fact we do precisely this on some of our drains where we use a simple constrictor instead of a full on valve to achieve silent reef tank Nirvana.
The third and equally important aspect to using a controllable pump is when they are equipped with a needle wheel impeller to power a protein skimmer. Just like the balance we achieve between the drain and feed water for our overflows, you can leverage some similar degrees of equilibrium with protein skimmers using controllable needle wheel pumps. We always had the ability to control the air intake and water level of all protein skimmers but now with a third parameter in the form of a controllable needle wheel pump, there’s much more flexibility in achieving a desired ratio between air and water volume, or wet and dry skimming, and likewise not running the pump at 100% will impart similar benefits to extending the lifetime and performance of the pump.
For this informative video we use the relatively newer Great White pump and Great White DC skimmer because they are part of the newest generation of controllable DC pumps, and it’s a perfect way to showcase basically the same pump running in either a centrifugal configuration for the return water, or with a needle wheel impeller powering a nice pipeless protein skimmer. We take for granted just how virtually all of the return pumps in the home reef aquarium market are controllable but we still see reefers not really leveraging their various benefits, so hopefully this primer will help to expand the understanding of how to make these pumps run cooler, quieter, and last a lot longer so you can spend more time with beloved marine fish and reef corals.