Precisely What Is Considered A Nano Reef Aquarium?

What is considered a Nano reef aquarium? How small is a nano reef fish tank? Is my tank to big to be a nano?

These are the questions you will always come across whenever reading a nano reef forum or any reef forum at that. I do not think there is a definite answer to this, I do however truly feel that anything over 20 gallons is not a nano and 15 gallons is pushing it.

In my view, a real nano, in all sense of the word is up to 10-12 gallons (not including a sump).
Can a nano reef aquarium be as successful as larger tanks? Do I need a protein skimmer, what about filters? Do I need to dose any calcium or alkalinity? Just how much water to do have to change once a week?

Unfortunately there is no decisive answers for these particular questions because every tank is different. There are though general arguments to follow for every reef tank.

The most significant factor in keeping any reef aquarium is water quality. You can have the coolest lights, the "best" additives, etc, if your H2O quality is not just right, you will not likely have a nicely balanced reef. The easiest way to maintain optimal water quality is by performing water changes. Since nano's have such low water volume, one can perform 50% water changes once a week without even drawing a sweat!

All you would have to keep up your nano reef tank is salt and an RO-DI unit! Yes, you still need the obvious items such as lighting, temperature control, water movement, food, etc, but you will most likely not require any type of tank water purification. No protein skimmer, no carbon reactor, no phosphate reactor and no mechanical filtration as well. You will most probably not even need to worry about dosing for calcium, alkalinity not even magnesium!

But how?

Simple, you will get EVERYTHING you need from a simple and easy water change! Keep in mind, you have a 10 gallon tank. Even if you mix a 5 gallon bucket of fresh salt mix weekly, you will be changing out roughly 50% of your water. A 50% water change will most defiantly replenish any calcium, alkalinity and magnesium and it will also get rid of all the "bad stuff" which a skimmer or sump would have removed!

The only issue I have with large 50%+ water changes is they could drastically alter your water biochemistry. This would be ok for a fish only aquarium, but if you have any type of coral, I would certainly not suggest it. What you could do is mix your 5 gallon bucket of fresh salt once per week BUT only replace a couple of gallons at a time, say every couple of days. This way you still get the benefit of a 50% water change once a week without shocking your corals with any large changes.

Significant note** Keep the mixed saltwater covered to protect it from particles getting in and to minimize water evaporation. If water evaporates, your salt mix will be comprised. As you are most likely already aware, salt does not evaporate, only water does. Make certain you check your salinity prior to dumping it in!