Aquariums - Is there a difference in tank configuration between freshwater and saltwater?
I'm an amateur fish keeper who is looking at buying a new 4ft tank setup.
While on the hunt for a nice looking cabinet and tank combination, I've noticed that most freshwater setups are designed for a canister/ hang on back / in tank filter, whereas saltwater is almost always designed as a sump configuration despite the same physical tank size and capacity.
Is there a reason freshwater tank setups are less likely to be sold in a sump configuration? Does salt benefit more from an overflow style of filtration then freshwater does? Should freshwater be pulling water for filtration from lower in the tank because there's likely slower water movement and therefore debris will settle on the substrate?
As a quick example, AquaOne have a "freshwater" range, and a "marine" range. They are available in comparable physical sizes, but the freshwater tanks are not drilled for sumps whereas the marine are. No matter how fancy / big you go in the freshwater configuration, you never have the option of a sump.
Freshwater list: https://aquaone.com.au/2015-04-16-04-47-04/2015-04-16-06-00-17/coldwater-tropical
Marine list: https://www.aquaone.com.au/2015-04-16-04-47-04/2015-04-16-06-00-17/marine-aquariums
Caveat: I'm quite a novice and have only kept freshwater setups.
From what I understand, saltwater tanks need extra equipment like protein skimmers as well as more tweaking and adjustment of water chemistry than freshwater. The sump provides a convenient space to do this without taking up space in your display. It's also where beneficial but perhaps unaesthetic saltwater tank components like live rock can be kept as well.
I haven’t had aquariums in years but I think this is on the right track. Also, with saltwater the larger the tank the more stable it’s going to be - so if you have maybe a 30 gallon tank with 10 gallon sump under, you are technically working with about 40 gallons, so there’s more wiggle room.
This is true of freshwater as well. More water means more stable temps, slower shifts in chemical balances.
There's definitely plenty of sump users in freshwater but canister filters are just easier so most people use them. Unlike salt water tanks which /u/Flocculencio said need way more stuff that would take over a lot of internal space and look ugly in a larger setup.
I know someone that has a rather large and very mature coral reef tank. He has a refugium (what you refer to as a sump) full of live rock, snails, shrimp, etc, critters that clean the water. He has a protein skimmer. UV sterilizer. Impeller pumps to simulate waves. He has to do weekly 55 gallon water changes every weekend to keep the level of water quality he wants. He uses very specific (read expensive) lighting to help deter the wrong kinds of algae growth and keep the corals believing they're actually in an ocean. Invasive pests, mineral and pH balance, it's an ongoing bio experiment.
He sells coral to kind of help with the costs, and regularly hears about people killing their entire tank. He even gives them his old water to try and help innoculate thier tanks. It's aquarium hard mode. Just doing fish wouldn't be quite as touchy, but close.
For my 30 gallon freshwater tank, I've found that live plants + snails + a piece of driftwood is a great combo for a stable tank. Admittedly this is ez mode compared to a coral tank, which I think is about as hard as they get, except possibly jellyfish.
We've got our full 30 inchs of fish (tetras and catfish), and we've gone as long as 7 weeks without a water change.
For us, we found keeping the algea at bay is striking the balance of light and air correctly. Too much or little keeps the plants from growing properly and frees the excess for algea to grow.
Everyone comments how immaculate our tank is, but it really just boils down to that plus an at-least-monthly 50% water change.
I used to run 6 planted tanks at home, and have a fair amount of experience even though its many years in my past. Sumps are hugely more common on saltwater setups - you can run them on freshwater but they're very rare.
I'm biased but I'd wholeheartedly encourage you to do a lot of reading on planted tropical tanks before you decide anything. For me they're by far the most beautiful setups, and although there's a fair amount of work to get one up and running, the established ecosystem of plants, community fish and also specific clean-up crew makes for a much easier maintenance life.
I'm in the UK so UKAPS was my forum of choice back in those years, but I imagine wherever in the world you are there's a more locally based forum.
Best of luck with your adventure!
As others noted, a sump is less common in freshwater because there’s less of a need for ancillary equipment in freshwater vs saltwater setups. But a sump can be nice for a freshwater display.
But sumps are also really important for water quality in a SW setup because they increase the system volume to create more stability in the system. They hedge evaporation, increase the bio capacity and oxygenation/ gas exchange.
You can use all kinds of substrates you wouldn’t necessarily want in your display, which could be really cool for a freshwater system, playing with different substrates in reactors and such.
I've got a few 4ft tanks with canisters, and a 6ft with a sump (repurposed ex-marine tank with a full length wier and combo Herbie and Durso overflow etc).
To my mind, sumps are hugely beneficial to both fresh and salt... But manufacturers don't seem interested in providing a freshwater sump option at all.
Obviously you can use a "marine" tank as a freshwater tank, but it got me questioning why there's an emphasis on canisters and HOBs for fresh when the marine tanks in the same size are only fractionally more expensive to have a sump. Why not push the sump in the freshwater categories too?
I was starting to wonder if I'd missed something. Noticed marine tanks always overflow whereas canisters pull from a lower level in the tank and thought that may be something important.