The Salty Side: Saltwater Aquariums for Beginners

How Easy is a Saltwater Aquarium to Maintain?

saltwater tank

If you are wondering how easy it is to maintain a saltwater aquarium, you’ll hopefully find this article helpful.  

I’ve given each section a star rating as to how easy, or difficult, each task can be.

The best advice I can give anyone who is wanting to go from freshwater to saltwater fishkeeping, is to read, read and then read some more!  The more you read about the hobby, the more you’ll understand it, making it easier once you start.  Forums are great too, although everyone does things a bit differently.  This is why I started this site.    

On The Salty Side, I’ve tried to make things as easy to understand as possible.  I’m constantly adding articles and information that might help anyone get started.  It truly is an amazing hobby, even if it can be very frustrating at times.  

So, is it easy to maintain a saltwater tank?  Let’s find out! 

Alternatively, for a far more in-depth look at starting you first saltwater tank, click here to download our ebook.

Mixing Water

The very first task any marine keeper will have to do is learn how to mix the right quantity of salt to the right volume of water to attain the correct salinity. This is simple in itself as all you will need to do is follow the instructions and wait for the salt to fully dissolve. Mixing water does not require a heater.

Unlike tropical tanks that only require tap water and dechlorinator, marine tanks require RODI water to successfully control nutrient levels. RODI is the abbreviation for Reverse Osmosis Deionisation, and refers to water that has been pumped directly from your household water through four filters of a RODI unit designed to purge the water of everything.

AQUATICLIFE Aquatic Life RO Buddie Plus DI Four Stage Reverse Osmosis Deionization Unit 50 GPD
  • ZERO TDS WATER- Produce up to 50 gallons of zero TDS water every 24 hours at an affordable price with the RO Buddie plus DI model, The RO Membrane will remove up to 98 percent of the TDS in water and the DI Mixed Bed Resin will remove the remaining TDS
  • SEDIMENT REMOVAL - The five-micron sediment filter cartridge traps particulate matter like dirt, silt, and rust with will affect the taste and appearance of the water
  • CARBON FILTRATION - The five-micron activated carbon reduces chlorine and conditions the water prior to the RO membrane



The purchase and set up of the RODI unit is pretty simple. Measuring the right amount of salt into the correct volume of water only requires a kitchen scale. 

Purchase of a Refractometer to measure salinity.

how easy is a saltwater tank - rodi water
Under sink RODI Unit

Water Changes

A tropical tank requires that the water be heated to the same temperature as the aquarium, and generally a gravel syphon is used to remove detritus, while the filter is cleaned too of accumulated detritus.  When carrying out a water change in a marine tank you also heat the water to match the tank water to prevent shock.

You will need to ensure that the salinity of the water in the tank matches that of the mixed water you have already prepared.  Depending on water movement in your tank, you may or may not have to blow settled detritus ‘dust’ from your live rock with the use of a powerhead/wavemaker.

It is generally considered counter-productive to syphon the sand, as you are disrupting the good bacteria that live there.  Syphon directly from the water column, sucking up any detritus you may have blown from the rocks, or if you have a sump, remove water from the sump.  Replace removed water with mixed water.



Checking your tank salinity against the mixed water may be a little difficult to start with, but you soon get your head around it.

Using a powerhead to clean the rock surface off is dead easy.

Salt Concentration and Evaporation

This is where tropical fish keepers begin to experience the main difference between keeping fresh water and saltwater aquariums. Maintenance of the correct salt level is essential in keeping a successful reef tank. The measurement of salt is made using a refractometer.

Salt concentration is measured in Specific Gravity or Salinity.  Ideal specific gravity for a reef tank is 1.023 – 1.026.  Ideal salinity for a reef tank is 33 – 35.

All aquariums have potential to lose water through evaporation. Evaporation is exacerbated through increased water surface agitation, through exposure to lighting heat radiance, and through the ambient temperature in the room.

Loss of water in a tropical tank does not affect the inhabitants in any way, however should water be lost in a reef tank, the salt becomes more concentrated and can raise the salinity beyond acceptable limits.  In order to maintain stable salt levels you need to be aware of evaporation in your system and counteract it by adding exactly the same amount of RODI water.

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Manual control – this will involve inscribing a mark on the glass of your tank or sump and monitoring the water level. You will need to add the appropriate amount of RODI water as often as daily in some systems. Monitoring of the actual salt level should be done with a refractometer to ensure you are keeping stable levels.

Automatic control – This is a preference of many marine keepers which makes stability far easier to maintain. It involves the addition of an auto top off unit (ATO) which monitors the water level in your system. Should the level drop, the unit will automatically re-fill the tank to the appropriate level from a reservoir containing RODI water. 

Purchase of a Refractometer to measure salinity.

Nutrient Control

Both tropical and marine tanks rely on the keepers ability to maintain low levels of nutrients (phosphate and nitrate), however it is widely accepted that marine tanks are far more susceptible to the results of poor management than tropical tanks are.

Excessive nutrients in a marine tank can lead to uncontrolled algae growth, the potential for cyanobacteria1, and an environment unsuitable for coral growth and colouration.  Poor control of nutrients is one of the most common reasons beginners can give up on the hobby.

Nutrients in a marine tank is a given. Therefore, from the outset, special attention should be paid to the method in which you plan to export (remove) nutrients.  Phosphate and nitrate do not remove themselves.

Your system, and the availability of space, will determine the method of control.



Control of nitrate and phosphate comes down to simply controlling what goes into your tank and what comes out of your tank. Too much overfeeding, or in fact fish, could increase both nitrate and phosphate. Not enough done to remove nitrate and phosphate from the system results in excessive buildup. It comes down to creating a happy medium.

This is by no means an easy task, in fact it is the hardest part about keeping marine fish.

If you are considering going into the saltwater aquarium hobby for the first time, I have made it as simple as possible for you by writing this ebook. It will help you sidestep all the mistakes I made, and set up a successful reef tank.

Click here for more information.

Testing Parameters

The testing of tropical tanks tends to centre around the PH, whereas marine tanks are somewhat more demanding.

Whatever your ambition, keeping a fish only tank, or an SPS dominant tank, putting a schedule in place to carry out regular testing of your water is extremely beneficial. Not only will this give you an in depth knowledge of the workings of your system, but will also warn you when to take action to remedy anything out of kilter.

how hard is it to maintain a reef tank

Test kits are many and varied with advocates for each and every type. In addition, there is no all in one test kit on the market.

Basic parameters that require testing are NO3 (nitrate), PO4 (phosphate), KH (alkalinity), Ca (calcium) and Mg (magnesium), although KH, Ca and Mg are only relevant when you begin keeping corals.  Testing can seem time consuming, but if a routine is established you’ll soon get used to it.



Once your preferred test kits have been purchased (a good starting point is Salifert, with almost unanimous agreement), it’s just a case of getting stuck in.

After carrying out the tests a number of times, you won’t even need to read the instructions anymore as it becomes second nature.

Water Clarity

Both tropical and marine keepers strive for water clarity.  Tropical tanks depend on water changes and a water forced through a filter which will catch any suspended particles and detritus in the filter media.  Carbon is also a useful tool in both aquarium types.

Marine tanks rely on the bio-filtration offered by the live rock2, then filtration through a sump or rear filtration system which will incorporate apart from other media, the use of a protein skimmer. It is a skimmers job to remove unwanted suspended particles from the water to help keep the water as clean as possible.

For more information on skimmers suitable to nano aquarium sizes, click here.

For larger aquarium sizes click here.

how easy is it to maintain a reef tank
Protein Skimmer

Aquarium husbandry will require the hobbyist to carry out regular tasks in order to maintain excellent water quality. This will include cleaning of the protein skimmer collection cup to ensure it works as effectively as possible. In addition, if filter socks or coarse sponge are used they need to be cleaned regularly.  If carbon is used it should be changed every 4 – 6 weeks. Carbon is primarily used to remove dissolved organics from the water which cause the water to appear yellow.



Each system is different, and what may work for one tank will not work for another. Generally speaking you should have one method of control for nitrate export and one method of control for phosphate export, although this is not absolute. A refugium for example has the capability of controlling both.

Research the causes of nitrate and phosphate to understand how you can minimise the introduction of them into your system.

Failure to monitor and maintain the correct levels will eventually lead to a tank inundated with unwanted algae and unhappy corals.

So there you have it!

There is a certain amount of difficulty determining the compatibility of fish with other fish, fish with corals and the correct size tank or water volume to accommodate your chosen fish.

There is also the undeniable difficulty that can arise with unwanted live rock hitchhikers, which need to be dealt with. However, once you have researched the fish you want to keep, and have rid your system of unwanted hitchhikers, the ongoing husbandry is all that is required.

It is a great hobby and once you get over the first few hurdles, you’ll find that it’s not that hard to maintain a saltwater tank.  Patience is a must!

Remember to research as much as possible before starting.  You might also find the following video useful:


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