One fun aspect of the saltwater aquarium hobby is that it is constantly evolving. Back when I started my first saltwater tank in the late 1980’s, live rock was virtually unheard of and protein skimmers were all air stone driven and very pricey.
Fast forward to modern day and the latest “breakthrough” in protein skimming has arrived: DC powered protein skimmer pumps.
Before I dive into why I think DC powered skimmer pumps are worth about 10 seconds of your time (at most), you need to understand why these pumps are being touted as the next best thing for protein skimmers.
Control
A DC pump gives you the option of variable speed control which mean you can now control how much water is entering your skimmer via the pump. An AC powered skimmer pump is either on 100% or off and the only way to control flow through the skimmer is by restricting the water leaving the skimmer through the output pipe.
The controllability of these DC pumps often includes a built-in feed timer that will shut off the pump for a number of minutes in anticipation of your sump filling with water. (Unless you are running a recirculating skimmer, a significant rise in water level in your sump can cause your skimmer to overflow).
Finally for controllability, a DC pump also can do a “soft start” meaning the pump starts at a low rpm and ramps up to full speed, potentially reducing broken impellers.
Efficiency
DC pumps are more efficient than AC pumps. In other words, it takes less electricity to get more performance out of the pump.
Sounds great right?
Combining the controllability and added efficiency of these DC skimmer pumps, why am I clearly not a fan of them? Because more isn’t always better.
First, I’ll clearly go on record saying that the added efficiency of these pumps is a good thing. Granted that the potential carbon footprint gain is very likely negated by the production and shipping of these pumps, trying to at least reduce the electricity consumption of our tanks can’t hurt.
That being said, one truth when it comes to saltwater tank hobbyists is that we love to fiddle with everything. We will over analyze, tweak, plan and re-plan to the point where some of us never get the tank started. Furthermore, the gains from these tweaks and analyzations are usually negligible at best. This fact is especially true with a DC skimmer pump.
Given that an AC powered skimmer pump is either on 100% on or off, the only gain out of the variable water flow of a DC powered skimmer pump is that you can turn it down.
Do I believe for a moment that if you dial back the setting on the pump that your skimmer will create large amounts of more or better skimmate?
No.
And if a manufacturer knew that less flow through the skimmer meant better skimmate production, don’t you think they’d just use that setting for the pump? Or go with a smaller pump all together? Why would they leave themselves open to a bad customer experience when they could give the customer what they want (good skimmate in an easy to use package) right out of the box?
Furthermore, introducing a variable speed pump into the already existing equation of variable air intake and variable water output from the skimmer, the number of potential combination of settings just went up – way up.
More combinations means less chance you’ll actually hit the “perfect” combination of air flow, water flow and water output – assuming this perfect combination even exists. Sure you reef junkies will relish the fact that you can spend days of your life trying to find that perfect setting. And I have no doubt that you’ll bask in the glory of announcing to the reef keeping world on your favorite forum that you’ve unlocked the puzzle of the perfect air and flow combination and now your SPS growth has doubled…overnight. For everyone else, you’ll likely try a setting or two, then leave the skimmer on full blast and go on with your life.
But how would you ever know that you hit that perfect combination? I highly doubt a significant increase in skimmate is going to happen by stumbling across the perfect setting. What’s more likely going to happen is that you’ll turn the skimmer pump down too far and skimmate production will drop because there isn’t enough water flow through the skimmer! Just because something is controllable, that doesn’t mean it’s performance will be significantly improved due to the controllability.
From a control standpoint, the feed timer feature of these DC pumps is nice for those of you that don’t have a controller, but I wouldn’t spend any money swapping out the pump on your existing skimmer for a DC pump. Instead, put that money towards the cost of a controller that can control not only the skimmer, but also the rest of your tank.
I will say the soft start feature is nice as impellers for pumps can be pricey and sometimes hard to find. Is the soft start feature important enough to me to want to switch to a DC powered skimmer pump?
No. Mainly because I’ve only ever had to replace 3 skimmer impellers or shafts throughout my whole saltwater career.
Finally, If I was shopping for a new skimmer would I add a DC driven skimmer to my list?
The only reason I’d consider a DC powered skimmer is if I couldn’t find a AC powered skimmer that fit my needs.
I love new toys for my saltwater tank, but I’m not interested in, nor do I recommend you paying much attention to this DC powered protein skimmer fad.
Strike protein skimmers are off your list for where to use a DC powered pump, and add a DC powered pump to this place