Large Tanks - Planning for Success

Building on last month’s topic of planning an in-wall tank, I want to expand on concerns with planning a large tank. Many, if not most large tanks are in-wall, so all the last month’s suggestions apply here as well. A big tank, however, has several “special” concerns in addition to the in-wall issues. Big is an obviously relative term that I’m going to leave undefined. I’ve set up two large tanks myself within the past year - my 450 gallon and a friend’s 400 gallon - and talked to numerous others on RC and other boards, and many similar themes and issues come up. Most of my suggestions will apply to anything around 180 gallons or more, but realize that the bigger you go, the more the following are concerns. Some of the obvious issues that most people think about and how to address them:

Weight: No doubt that this will take some planning. With a tank that is relatively small, your buddies can easily handle moving the task. When you get a large tank, however, this becomes an issue of both safety and logistics. The first questionis whether you want acrylic or glass. Acrylic will be much lighter and you probably will be able to move it with some local reefers help, even if it is very large. Acrylic, however, has some downsides. The main downside is that it’s easily scratched. Instead of getting into a debate of glass versus acrylic here, I’ll just say if you do plan a glass tank, much more planning will be involved. Be sure to measure, ensuring that it easily can go through all the turns, doorways, etc. If your tank is really large and glass, I would highly recommend you consider professional movers. While this will cost you a few hundred dollars, they will insure your tank against damage, and, being professionals, you will not have to be concerned with the safety of volunteer movers.

Cost: The bigger the tank, the more expensive it is. It’s really important in a big tank to plan. An inefficient pump is not too big a deal on a small tank, but when you’re burning 3 figures worth of electricity per month on your tank, you’ll usually find that efficient equipment will quickly pay for itself. Don’t buy a large tank and then figure out what you need (unless you have unlimited funds of course). Plan it out, add it up. If you can’t afford it, either downsize, wait, or figure out alternatives. The worst thing you can do is set up a big tank and then not be able to keep it properly maintained.

Plumbing : Again, there is nothing really special about the plumbing for a big tank, except that it just requires more planning. Are you going to run closed loops? What about remote sumps? A chiller? All of these things need to be decided and planned. I highly recommend you plan the placement of all your piping before gluing a single joint! Use unions everywhere that could possibly need one. A $20 1.5” union may seem pricey, but the ability to remove and replace things is worth it many times over. You may want to think about bypass loops and alternatives that let you clean the plumbing and pumps with muratic acid every so often, etc.

Chemical supplementation: This one is often overlooked. In a small tank, it’s very practical and costeffective to dose 2 part additives to maintain calcium and alkalinity. Alternatively many put kalkwasser in the topoff water. While it’s certainly possible to continue to do that in a larger tank, the time and long-run costs make a calcium reactor well worth it in most circumstances. This is money very well spent!

Access: When you have a small tank, it’s pretty easy to get in it. You reach over and can touch the bottom everywhere and there aren’t many issues. A large tank is an entirely different story. You have to plan here (Do you see a theme? A large tank takes more planning .). Once you start getting more than either 24” deep or wide, you will encounter challenges. Some prefer the look of deeper tanks, however, once you go 30” or more, you will really need to think about how to access the bottom of the tank. I’ve seen many people say that this isn’t important, but nothing is further from the truth. You’ll always have to rescue a fallen frag, remove a dead snail shell or all kinds of little stuff. You need that access. Anything over 30” from the access is problematic. In other words, if you have no front access, a tank wider than 30” will be very difficult to access the front. There are always ways around these issues. Some even have support racks over their tanks to lay on to access the whole tank. With proper planning though, this is only necessary in extremely large tanks, but access is extremely important and must be addressed in everything from canopy (if not in-wall) to room design (if it’s in-wall) to lighting support (possibly movable). A few other considerations that aren’t unique to big tanks, but that, again, become more challenging are lighting (deeper means more wattage, wider means more bulbs, etc), heat (do you need a chiller, what about type of heater, etc), filtration (skimmer, etc) circulation (closed loops, wave devices, power heads, etc), and auto-topoff (a must in a big tank).