Starting A Saltwater Aquarium - Part 2 - Bringing Nature Home (researching Equipment)

  • #1
HI everyone,
Welcome to Part 2 of my Saltwater adventure.

For those that have read Part 1, welcome to the next step in my journey, for those that haven't read it: Starting a Saltwater System - Part 1 - Where to start (Research)

In Part 1, I covered the fundamental research that I undertook before starting my tank... To re-cap, I researched:
The Reefs of the World
- Appreciating the scale of the project
- What Makes a Reef

Reef Life
- Anemones
- Corals
- Fish

Deciding on a Setup
- Reef
- FO

So by now, you've probably chosen what sort of setup you would like to keep.

The next step in the process was understanding how to bring this diverse eco-system into the home.

How do we simulate the Reef environment in the home?
Note: By reef, I mean the ocean, but given all marine fish typically come from a reef, it's easier to cover the generics of the reef environment
  • Water Chemistry
  • Filtration, Nutrient Export & Flow
  • Lighting <more important for reefs>

So Step 1, Water Chemistry
I put Water Chemistry at the top, because without first understanding this, it's kind of hard to get your head around the rest.

Natural Sea Water is a somewhat complex composition of many elements.

There are the standard elements that most Freshwater keepers are familiar with, pH, ammonia, nitrite, nitrate, and carbonate hardness (KH). KH is often referred to as alkalinity in the marine environment.

But what separates Saltwater from Freshwater is.......... SALT, and we're not talking aquarium salt, it's natural salt. Enter terms such as Specific Gravity (SG), salinity, conductivity <and to be honest, I forget the rest>, but essentially, all of these terms refer to 'how much salt there is'

Specific Gravity - is a 'generic' measurement of how 'heavy' the water is. It is a chemistry term used to measure the weight of any liquid, and is often used as a comparison for quality/purity of a liquid. But I digress, in the marine environment, we use SG to 'measure' how much salt is in the water. But what does it mean

- Pure water has a specific gravity (SG) of 1.000, it basically means that 1 litre of water weighs 1kg
- Natural Sea Water <typically> has a specific gravity of 1.026 - meaning that 1 litre of NSW actually weighs 1.026kg - Salt water is heavier than pure water!

Salinity - is a 'generic' measurement of the 'concentration' of salt in the water. Measured in ppt (parts per thousand).
- Pure water has a salinity of.... you guessed it... 0
- Natural Sea Water has a salinity of approx 33-34ppt. This means that for each litre of water, there is 33 to 34 grams of salt.
Note There is fairly consistent and accurate correlation of SG to Salinity

Conductivity - is measurement of the water's ability to conduct electricity, but to be honest, I didn't research this too much. SG and salinity were enough for me.

So which measurement is better? Well, conductivity is said to be the ultimate measurement, but it's more expensive to test, salinity is quite accurate, and SG is also a good guide. Ultimately, it comes down to the equipment you use. I highly recommend a refractometer, which can test both SG and salinity.

OK, so now we've covered the basics of Saltwater chemistry, let's look at all the other things you've read about. Most of these, in fact all of these, really only apply to a Reef system.

Corals depend upon 3 primary elements, Magnesium (Mg), Alkalinity (KH) and Calcium (Ca), and can be sensitive to Phosphates (PO4) as well as some of the trace elements such as Strontium (Sr), Iron (Fe) and a few others - to be honest, I only worry about the 3 primaries (for now). If you've decided on a FOWLR setup, then these are not important to you, but for a reef keeper, understanding your corals requirements for these elements is important

Testing Equipment
Ok, so now we have a base understanding of Saltwater chemistry, what testing equipment do I need?

Well, similar to Freshwater you should have:
High Range ph (must go into the 8's), Ammonia, Nitrite and Nitrates
You will also need some way of measuring salt content. A hyrdrometer is a good guide, but can be inaccurate, so I recommend a refractomer. Testing conductivity is not necessary for most.

For reef keepers, you should also consider adding to your testing arsenal:
KH, Magnesium, Calcium and High Resolution Nitrate (capable of sub 5ppm) and High Resolution Phosphate (for Phosphate, I recommend the Hanna Checker)
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  • #2
Marine Filtration and Flow

So we've figured out our test kits, and we have a base understanding of salt water chemistry. For me, the next step was understanding the filtration of the marine environment.

By filtration, I'm going to focus on the process of the nitrogen cycle in the marine environment, and removal of organics.

Note: For me, coming from a Freshwater background, this was the hardest concept to understand and get my head my around

Before we go much further, let's first consider what we know about the ocean, and the reefs. Oceans are the largest bodies of water known to man, they have tides and currents (enter flow) and on a reef, there is a lot of rock work. Waves crash against the rocks, and the large body of water dilutes the concentration of elements, and the currents carry them away.

So how do we replicate this in the home aquarium ???

Coming from a Freshwater background, I was stuck on the concept of having bio-media to perform the nitrogen cycle.

I had to change my thinking, and go back to the basics of beneficial bacteria - that is, BB will grow on any surface in the aquarium, the more porous the better.

If we think about the bio-media we have in a Freshwater filter, it is typically highly porous (bio-balls, substrat from Eheim, bio-max from Fluval etc).... What about rocks? <ponder this for a bit>

But filters are external to the tank aren't they? (HOB/Canister) What if I change my thinking, and think of the whole Marine setup as one big filter.... how does that change my perception of a marine filter.

But filters require flow to move water over/through the media don't they? Yes they do What if we put some powerheads in the tank to create the flow in the tank?

<starting to get it now?>

Enter LIVE ROCK....... By having sufficient Live Rock, we effectively have our bio-media, do we not? It's highly porous, great for beneficial bacteria to grow on.

If we add powerheads to the setup, we are now flowing water around and over the live rock, or bio-media, thus we have bio-filtration in our tank...... yes?

Not to mention we are replicating the tides/currents of the ocean (remembering, most specimens are hand caught from these environments)

But what about mechanical and chemical filtration? Well, on a reef, it simply gets washed away with the current, but in the home aquarium it's not quite that way, and we often need to supplement the mechanical filtration with some form of external mechanical filtration, enter the sump (more to come on sumps). But, so far, I have not required any form of mechanical or chemical filtration in my system.

So now we have our bio-filtration, we can safely convert ammonia to nitrite, and nitrite to nitrAtes.

But what is all this talk of Protein Skimmers?
Ahhh, good question. Have you ever seen waves crash, and the white wash it leaves behind, often leaving a browny residue?

The browny residue is in fact, what is referred to as Dissolved Organic Carbons (DOCs), or for want of a better term, Proteins. A protein skimmer is a device that injects lots of micro bubbles into a water column, the bubbles attract the DOCs and transport them into a collection cup, leaving a brown 'tea' like residue in the cup, called skimmate.

What the protein skimmer does, is help to remove the left over food and other organics from the water, before they have a chance to decompose and add to your overall nitrate level.

And what about Refugiums/Macro Algae/Nutrient Export?
Ok, the first thing I learnt, a sump is not a refugium.

In a Reef system, corals and to some extent, inverts (Shrimp, Snails etc), can be sensitive to nitrates and phosphates, so the reef aquarist has sought ways to reduce these concentrations without daily water changes.

It is not uncommon to hear a reefer talk of Phosphates at 0.02ppm and nitrates of 1 to 2ppm or less. To help control these parameters, marine aquarists, or more specifically reefers, have used nature to help 'export' these nutrients from their system. One of the best methods is to use algae, primarily macro (or large) algaes such as chaeto. These algaes are typically housed in what is known as a refugium. Water from the display tank is fed through the "fuge" to provide nitrate and phosphate to the algae, the algae feeds on these elements, and thus reduces the concentration of these elements.
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  • #3

What is a Sump
A sump, by definition is a a low-lying place, such as a pit, that receives drainage.

In the aquarium environment, sumps are typically located under the Display Tank (DT). At the top of the DT there will be bulkheads drilled into the tank, or an overflow ledge known as an overflow weir. As the water falls over the weir, it drains into the sump, and is then returned to the DT via a return pump.

Click the for the animation. Image courtesy of: What is a sump? | Melev's Reef

Why use a sump?
Well this is an excellent question, with very plausible reasons:
  • Increases water volume
  • A place to store equipment (heaters, reactors and skimmers)
  • A place for the Refugium (if using)
  • A place to dose supplements
  • Maintains water level in the DT
  • A good place to add top-up water
  • Provides a way of surface skimming the DT (as distinct from Protein skimming)
  • Some where to run mechanical filtration

Sumps will typically be divided into sections, using baffles to separate each section. There is no right or wrong way to configure a sump, but the typical arrangement is a Skimmer Section followed by Refugium (if using) and a Return Section. Some sumps may have a fourth and fifth compartment for Nitrate and Phosphate reactors and to propogate Coral frags.

Baffles are used to help reduce the bubbles in the water. With the skimmer injecting millions of micro bubbles, without baffles, those micro bubbles would otherwise be returned to the DT, which is aesthetically displeasing and can trouble some fish.

So with this in mind, I designed my sump as a three compartment sump. I have two drainage pipes into it, one drains into the skimmer section, the other into the refugium (which houses extra live rock). The skimmer section has baffles to reduce bubbles flowing into the return section in the middle.
EDIT Dec 2014: For details of my sump, refer post #6 and #35 of this thread: 20 Gallon Sump (actually, it's a pretty good thread about sump setup)

As water evaporates from my system, I simply add more RO water to the return section.

There's plenty of information out there about sumps, and melevsreef is probably one of the best I've seen.

Putting it all together - Total Flow
One of the hardest things to measure in the Ocean is actual flow rate of a Reef.

How does one measure how quickly the water is turned over? The simple answer is we can't, there's too many variables to consider. However, over the years, Reef aquarists have been able to establish a set of guidelines on the total flow required for a healthy reef system.

A guide to flow rates required
FO/FOWLR only system - approx 10x turnover per hour
Reef with soft corals, LPS - 20x turnover
Reef with SPS corals - 30x turnover (I have even read of 50 and 60x turnover)
Sump - approximately 5x turnover.

So in my system, a 250L (66G) Display tank, I'm aiming for a total turnover of at least 30x = 7500LPH (1969GPH), thus I have
Return Pump - 1,200LPH
Skimmer - 850LPH
Powerheads - 2 x 5,000LPH

My total turnover is therefore approx 12,000LPH (3,100GPH) or 48x, with a sump throughput of 1200/250 (4.8x)
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  • #4
What about Lighting

Ahh, lighting, one of the most diverse topics in reef aquaria.

In the natural environment, the only light source is the sun, so we must aim to replicate the sun in our home aquarium. Over the years, reef aquarists have tried many technologies to achieve this, the most common are T5HO, Metal Halide, LED. Each has its own merits and pros and cons. I'm not going to go into these here, there's plenty of info on the web about lighting systems for reef aquaria.

As with a planted Freshwater system, lighting is referred to in Kelvin temperatures, along with a concept of PAR (or Photosynthetic Active Radiation), or in laymans terms, how deep the light penetrates the water.

Actinic lights
What are Actinic lights? Well simply put, actinic lights replicate the UV spectrum of the sun that is known to benefit the growth of corals and their symbiotic zooxanthelle. They also add a wonderful aesthetic dimension to a tank.

When considering lighting, for a reef setup you should consider your lighting carefully. You want to provide a high quality broad spectrum light combined with actinic lighting to provide the UV. You want to make sure your lights are capable of penetrating the depth of your tank. You should also research the corals you wish to keep, and their specific lighting requirements.

Personally, I opted for a LED 50/50 white/blue fixture with built-in moonlights and a sunrise/sunset timer.

Guys, that's about it on researching equipment, but if you have any questions, please feel free to ask. For a full run-down on the equipment in my tank, please check out my member spotlight (link is in my signature)

Follow the learning: Starting a Saltwater System - Part 3 - Designing, Setting up and Running your system
  • #5
Hey ryan I just wanted to thank you for top notch info youv provided here youv really helped me alot
scotty b
  • #6
thank you very informative
Tigress Hill
  • #7
Thank you so much!♥
  • #8
As a new member here I wish to express my sincere appreciation for your effort in putting together this informative work.
  • #9
Great set of links. Have read this multiple times now.
  • #10
As a new member here I wish to express my sincere appreciation for your effort in putting together this informative work.


Sent from my Supercharged GS3 via Tapatalk 2
  • #11
Corals depend upon 3 primary elements, Magnesium (Mg), Alkalinity (KH) and Calcium (Ca), and can be sensitive to Phosphates (PO4) as well as some of the trace elements such as Strontium (Sr), Iron (Fe) and a few others - to be honest.....

Are these elements, Mg and Ca introduced into the water column through salt additives or would I need to add Mg an Ca supplement and will these, supply the minerals needed for fish osmoregulation or does live rock provide that?
  • Thread Starter
  • #12
HI Macca,
If you're using a good quality reef salt mix, it is often not necessary to supplement Ca, Mg, Alk. But if you do need to dose, there are a couple of ways to go about it:

Red Sea, Seachem (AquaVitro), Kent Marine all have a line of liquid products for all reef elements - these can be hooked up to auto-dosers, or dosed manually. Liquid supplementation is probably one of the more common in today's aquaria.

You can buy powdered forms as well, and mix your own.

Ca is also often dosed using a reactor - aka a Kalkwasser reactor.
  • #13
As water evaporates from my system, I simply add more RO water to the return section.

Would I need to add salt with RO water top up or does evaporation have no effect on salinity? I could simply add an automatic top up to the display tank yeah?

One of the hardest things to measure in the Ocean is actual flow rate of a Reef.

Is there a benefit to replicating the natural movement of high and low tide of the ocean with a wave maker on a timer?

With lights.... could I just buy high light to grow any type of corals and does high out put light have any effects on algae or is algae mainly a high nutrient issue in sw tanks?

Thanks heaps for all the info ryan.
  • Thread Starter
  • #14
You've missed part 3 of the adventure
Starting a Saltwater System - Part 3 - Designing, Setting up and Running your system

I'm not sure if high/low tide simulation would be any benefit. Maintaining good flow/turbulence in the aquarium is important though.

Lighting: Just like FW, lighting can and does affect algae growth levels. What intensity of light you get depends on what you can do with the height it's mounted.

If you can vary the height your light is mounted, or vary the intensity, then go high intensity to start. You can always bring the light down closer to the tank, or ramp up the intensity if needed. If you can't, Start with lower, but plan for expansion.
Sharon Sangston Degnan
  • #15
Why do people measure in liters? I have a 120 gallon, ang all my equipment is gph, liters confuses me, js
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  • #17
HI Sharon, respectfully, most of my measurements include a Gallon conversion, there is also a calculator at the bottom of the page that can convert for you. Too, for the record, all measurements of GPH that I use are US G, not UK G.

Why do people measure in liters? I have a 120 gallon, ang all my equipment is gph, liters confuses me, js
Imperial and US measurements are difficult to calculate - it is much easier to work in metric, and convert the result to an alternate system.
Metric is also the most widely used measurement system in the world.

1 Litre is always 1 Litre/1000mL, irrespective of the country
1 US Gallon is 3.78541 litres
1 UK Gallon is 4.54609 litres
That's a big difference

Fishlore is not limited to the borders of continental USA
  • #18
when you talk of flow rate, and using all the different flow rates together, am I right in thinking the powerheads just pump water through themselves to create turbulence and the skimmer flow is only in the sump or does the skimmer effect the dt?
  • Thread Starter
  • #19
I generally try and work on 5x flow through the sump.

The sump is part of the whole system, it's an extension of the main tank (like a giant canister), and the skimmer serves the whole system too.

Powerheads keep water flowing around all your live rock, and help to make a 'current' in the tank.

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