What Do You Need To Do To Successfully Start A Saltwater Aquarium?


As with any aquarium, starting a salt tank is all about researching, and researching loads!

You want the biggest aquarium you have the space and money for, and ideally, you will have a tank with a sump. A sump is a separate tank that sits underneath the display tank. The sump houses all of the filter media, live rock rubble, skimmers, heaters and reactors, etc. And the tank water passes through the sump at the rate of 10+ times an hour, keeping the water pristine and clean.

You will also need a good quality protein skimmer. The protein skimmer quite literally works 24 hours a day and skims the water for any protein. It collects uneaten food and detritus at a constant rate.

You may need a reactor (or various reactors). A reactor lives in the sump and keeps phosphate and / or nitrate levels in check by ways of various media. Low phosphates and nitrates are a must in a saltwater tank in order to keep nuisance algae to a minimum, and corals healthy. You could also have a refugium in the sump for this purpose, a fuge (refugium) is a space to grow macro algaes and seaweeds, etc. This also helps the battle against phosphates and nitrates as various algae, seaweed, and plants will consume them in your sump. However, you’d need a small T5 light in the sump for this.

Do you want corals or FOWLR? (Fish only with live rock)

Corals: If you want corals, you’ll need either high output T5s or good quality LED lighting. Soft corals are relatively easy to keep but lps and sps can be a little bit trickier and require specific elements dosed into the tank, at specific times, for food, etc. If you’re thinking about any corals, again, research, research, research! I wouldn’t advise adding corals until you see signs or coraline algae, this is the pink and purple hard algae found in established tanks and is a good sign of your tank being ready for corals.

Live rock: You’ll need a good amount of live rock, or a man made equivalent, about 1kg per 10 litres of water is good. Live rock will become a big part your filtration as it is highly porous and will house huge amounts of nitrifying bacteria that will help keep your water clean. The live rock will work in tandem with some wave makers.

You’ll need at least 2 wave makers, but possibly more depending on your tank size. These will stop any dead spots, which will help prevent cyanobacteria settling in the tank. They will also keep the water flowing through the live rock, which, in turn, will keep the tank water free from harmful toxins as these are consumed by the nitrifying bacteria deep within the live rock.

You’ll also need a good substrate, substrate made up of crushed coral and ocean sand is great as it also helps keep the pH a little higher. A pH of about 8.2 - 8.4 is ideal for saltwater.

A good quality salt, or pre-made saltwater will also be needed. It doesn’t matter if you buy mixed or you make it yourself. Either way, you will have to change about 15 - 20% of the water every 10 days to two weeks to keep the trace elements In the water topped up and the tank healthy.

A source of rodi water is also needed. Salt water evaporates faster than fresh water, but the salt itself doesn’t. Once you find your sweet spot in the tank, a level where the salinity / specific gravity are all spot on, you can either mark the tank and top up to that line daily or get an auto top up to top up for you. Without doing these regular top ups, the salinity would get too high and put the tank at risk.

You’ll also need a refractometer so you an keep an eye on the salinity and specific gravity. I would always check this daily. A FOWLR tank would be fine at about 1.021 specific gravity. A tank that houses inverts, like shrimp, crabs and snails, would need 1.023 - 1.026 and corals need 1.026. Fish are fine at 1.026 also, so its not a case of either or.

You’ll need a good quality salt specific test kit so you can monitor your water regularly.

It can be tricky but you can also run a tank on live rock, wave makers, and a hang on skimmer alone. To do this successfully, you would need 1kg of live rock per 10 liters of water and you would need to stock fairly lightly. The hardest thing about doing it this way is ensuring that you have enough flow and no dead spots in the tank. Several wave makers would be needed to keep all of the water flowing through the live rock (natural filter).

Canisters can also be used, but these can be nitrate factories and in a lot of cases so they require alot maintenance. All this being said, If you have a tank with a sump, you’ll be in the best position. Not only is a sump the most efficient way to filter a saltwater tank, but you get to keep all of your mechanics hidden away underneath, leaving your display tank free of clutter.

You’ll have to make sure that you have a well established nitrogen cycle in place before adding any fish, Ive previously cycled a salt tank with a raw prawn to about 4ppm of ammonia. You have to remember that it’s not like fresh water where daily, or even thrice daily water changes are an option. If you have a problem, salt water is expensive so you don’t need to be making any mistakes that would lead to several water changes. It’s also not so good for the tank as its a finer balance with salt and easier to knock things out of sync.

It seems like a lot to take in, and I have probably missed bits still but there’s a lot that goes into making a successful salt tank, and more still for a living reef. I’ve probably said it a few times In this blog but the most important thing is research, research, and research some more!

So... what do you think? Please leave me a comment.


  • Christi: Excellent information! Its understandable why saltwater tanks are so intimidating.
  • Paul Roney: Thanks Christi!
    I don’t mind doing blogs and love to help where I can, my downfall occasionally is my written English! I can talk plenty but putting it down in text is sometimes a struggle!
  • FishObsessed: It took me about 2 years to finally take the plunge, so far so good. :-) I have gone "old school" using canister filters filled with man made reef, a lot of man made reef in the tank as well, a gyre wave maker, hang on skimmer.
    The lights are all singing all dancing and they should really make me a cup of coffee every morning with the amount they cost.........
  • Paul Roney: Haha! Mines 1 sugar and milk!
    Canisters do work but they can be nitrate factories without proper maintainence.
    I’m looking at an aquaone mini reef 120 in the spring, some of the bits you get with it are a little bit budget I can change them over time, it’s all there for a start though and I like extra space for a fuge. All all I’ll have in my sump is sponge / floss, rock rubble, a skimmer, heaters and a nice little fuge... the fuge excites me the most! Lol Such a great, natural way of keeping phosphates and nitrates at pretty much at 0.
  • FishObsessed: All the filter media that came with the canisters was taken out and they were filled with Real Reef that was bashed with a hammer to turn it into rubble, that was fun :-) only sliced my finger open twice :-(
  • Vale: This is a very helpful blog! I would love to have a saltwater tank one day... when I have the place, time and money for it :D
  • Paul Roney: Thanks Vale! It’s certainly not a cheap side of the hobby, but something I’m looking forward to having another go at in the spring!😊
  • Vale: Good luck :)
  • Paul Roney: Thanks!
    I’ll be sure to log my progress on here! A living reef is, for me, as good as it gets!
    It was only a forced house move that forced me to step back in 2015, not a choice 😊
  • Vale: I look forward to seeing it :D
  • big_sw2000: Brilliant blog. I’m too going to delve in to salt water. After diving the red sea I imagine something similar in my lounge lol. I know it’s a dream at the moment. But one day a live reef setup will happen
  • Kev: Its also a dream for me to have a saltwater aquarium.
    Excellent blog, Paul.
  • Paul Roney:

    Thanks Steve, and Kev! You really should venture into this side of the hobby when the time is right for you! There is a lot to learn, but in principle it’s not too different from fresh, its all about looking after water!!

  • Fully_koalafied:

    Amazing blog Paul! I remember this blog helping me loads when I first started out. Good stuff :)


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