Beware These 5 Pitfalls When Buying Used Equipment for Your Marine Aquarium

Used saltwater aquarium equipment can be found on a plethora of websites

Used saltwater aquarium equipment can be found on a plethora of websites

There’s no question that setting up a saltwater aquarium can be a costly proposition. One way to help defray those initial expenses is to buy used equipment and materials when possible. There’s always someone upgrading to a new system, moving to another town, or taking a hiatus from the hobby who has gear to part with—and usually at a substantially lower price than you’d expect to pay for these items new.

Indeed, shopping for used equipment can turn up some terrific deals. However, it’s important to enter any used transactions with your eyes wide open. If you aren’t careful to avoid the following 5 pitfalls, your “bargain” investments could easily end up costing you much more in the long run than you anticipated.

#1 The fixer-upper tank

So much is riding on the structural integrity of an aquarium that you might want to pass by any used tank that needs seam work (unless you’re really confident in your skill with silicone) or other repairs. Certainly, a cracked or chipped glass pane should be considered a deal breaker—otherwise, it may eventually become a tank breaker that dumps gallons of water all over your floor, doing untold dollars worth of damage.

#2 The incomplete puzzle

This describes that irresistible used device, such as a protein skimmer or calcium reactor, that turns out to be missing a tube, valve, clamp, nozzle, gasket, or other gadget or doohickey vital to operation. You might be able to track down a replacement part—but then again, you might not.

#3 The functional antique

This piece of equipment comes complete with all the necessary accoutrements and does the job it’s purported to do. The only trouble is, it’s obsolete and better products are now available on the market. You may find you’re disappointed with its performance and the fact that replacement parts, if needed, are difficult or impossible to come by.

#4 Medication contamination

Our fourth pitfall can be a major concern with rocks, substrate materials, and other calcareous hardscape items acquired used. Certain medications, particularly copper-based ones, tend to bond with these calcareous materials and can end up leaching back into your aquarium. In a system containing corals or other invertebrates, this can prove deadly.

#5 The DIY disaster

Some hobbyists are extremely competent do-it-yourselfers and can successfully “MacGyver” just about any aquarium component out of bubblegum and duct tape. Then there are those who would probably be better off leaving the manufacturing to professionals but enjoy dabbling in DIY projects nonetheless. Unless you’re absolutely certain that DIY aquarium stand or reef-lighting fixture was crafted by one of the MacGyver types, you’d be well advised to spend a little more for a commercially manufactured model.

What have you bought used?
So, fellow salties, if you’ve ever bought used aquarium gear, we’d love to hear how it turned out. Share your story, good or bad, in the comment section below.


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About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. I have bought a used protein skimmer, LED light unit and System controller with all working 100%. It helps to know the person or source you are buying from. Many Pet stores sell used items and are good as long as they stand behind such product.

    • Jeff Kurtz says

      You’re so right, Tony! It definitely helps when you know the seller is reputable and stands behind used items.

  2. I love used equipment. However, it’s buyer beware. It’s especially helpful to know a lot about what it is you’re purchasing, and that you trust the seller. I recently bought a GEO Ca Rx for about half of what George gets for one that hasn’t seen water. It needed a bit of elbow grease, but it came from someone I know as a reputable hobbyist in a club I’m a member of. One time I bought a Vortech MP40 at he Cleveland spring time swap for $80, and later swapped it for 3 used Tunze 6100s and a controller that I now control with an Apex I bought used… You get the idea!

    Know your equipment, ask a lot of questions, and follow the rules laid out above and I’d absolutely recommend used equipment. Buy that tank you need to reseal and you’re on your own!

  3. I bought a used protein skimmer. when i turned it on it sounded like a engine. Had to replace the impeller. With the cost of the used skimmer and new impeller, i could have spend $20 more for a brand new skimmer. Lesson learned.

    • Jeff Kurtz says

      Sorry about your misfortune, Jon! No doubt other readers will benefit from the wisdom of your experience though.

  4. Bought a used corner fish tank and the seller claimed everything works. We went to see the tank and we agreed to buy it. Went home grab some money and went back the seller pack everything up and have it ready to put in car. How convenient? (Red flag) We didnt get a chance test the light. So we got home plug in the light unit guess what? It didnt turn on. My partner hope it was a fuse. So he changed and didnt even do flick. We texted the seller and told her that the light wont turn on and we want a refund. She replied and argued that the light was still working when she last tested. We even sent her the pictures of the bulbs. It was all corroded. She didnt even reply anymore after that . So we took it to one aquatic shop to have it tested and they were nice enough to do it for us. Yup a dead light unit. And to replaced it will cost over 100.
    So my adivce is TEST TEST TEST and make sure everything work before you give them the money.

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