Maintaining The Right Phosphate Levels

Phosphates are highly reactive compounds that are essential to living creatures. All living things use phosphates both as a source of energy and for bio-chemical reactions, vital to their continued functioning.

In your aquarium, phosphates will be one of two forms:

• Inorganic (orthophosphate)
  Phosphate in this form is water soluble and plants can easily absorb it.
• Organic
  This is phosphate that’s bound chemically in cells. In order for it to be reactive, bacteria must first break down the cell to release the phosphate.

The main concern of having excess phosphate in your saltwater aquarium is that algae uses it for food. At the mild end, having excess algae is annoying because they grow on rocks, aquarium tank walls, and other surfaces. If this continues, your water will eventually turn green and become murky.

On the other end of the spectrum, in a severe outbreak, the algae will consume and deplete oxygen from your aquarium, eventually killing all living creatures.

However, algae growth need a supply of phosphates, nitrates, and light (artificial or natural). By keeping any one of these three low, you can control algae.

But by keeping all 3 in the correct balance, it gives you some latitude, in case another factor becomes unbalances for some reason.

If you’re maintaining a reef or semi-reef tank and you’re concerned about coral growth, phosphate levels higher than 0.25 ppm, it can inhibit their growth.

Maintaining the right phosphate balance is vital to your saltwater aquarium ecosystem.

Phosphate Sources

There are two main phosphate sources in your saltwater aquarium:

• Internal sources
  There are several sources that originate inside your aquarium
  • Dead plant material
  • Feces
  • Uneaten food particles
  • Bacteria
• External sources
  These are sources you can control through careful monitoring
  • Water supply
  • Additives in foods (i.e. flakes, frozen shrimp)

Controlling Phosphate Levels

The best way to control phosphate levels is to control their influx. The primary source of phosphate in a saltwater aquarium is through the food source. 5 grams of fish flake food can raise the phosphate levels by 0.5 ppm.

Ideally, the phosphate levels should max out at 0.5 ppm and should hover around 0.1 ppm.

If you keep reef or semi-reef tanks, the live plants and organisms living on the rock will absorb and use the phosphate, helping control their levels.

Ironically, you can use one of the major concerns with high phosphate levels to control it: algae. By keeping macro algae (i.e. filtration system, sump, refrigerium), because they consume phosphate, they can keep phosphate levels low.

Along the same lines, live mangrove plants are highly effective in binding water soluble phosphates. These plants are so effective at not only removing phosphates but nitrates and other organic material, they stopped using protein skimmers.

Protein skimmers can help control phosphate levels by removing excess organic material (i.e. feces, uneaten food particle) that will break down into nitrates and phosphates.

Phosphate Test Kits

Phosphate test kits are useful in monitoring phosphate levels. However, they can only measure inorganic phosphate that’s dissolved in your saltwater.

Saltwater Aquarium Water Quality

Your saltwater is the ‘air’ that your fish, your plants, and other living organisms breathe in your saltwater aquarium. Having poor or unbalanced water quality is one of the fastest ways to kill your aquarium ecosystem. There are several factors that need to be carefully balanced against each other to make the optimal water for your fishies.

General Hardness

General hardness measures mainly calcium and magnesium content. Unless you’re raising sensitive fish or plan on breeding, general hardness isn’t a large factor in aquarium health.

It is important to know your water’s general hardness level and pick your aquarium residents (fish, plants, crabs, snails, etc.) that can live in your water.

Degree (GH)	PPM	Defined
0-3	0-50	Soft
3-6	50-100	Moderately Soft
6-12	100-200	Slightly hard
12-18	200-300	Moderately hard
18-25	300-450	Hard
25+	450+	Extremely hard

Carbonate Hardness (KH)

This measures the carbonate and bicarbonate content of your water. Carbonates act as shock absorbers and help buffer your water’s acidity and keep your pH levels stable.

Depending on your tank requirements, you probably want to keep your KH around 70 ppm.

Although there are better ways to control your KH levels, in emergency situations, adding baking soda will increase KH (and decrease acidity) while distilled water will dilute disolved carbonates and decrease KH.

If you need to make changes quickly, be cautious and start with small amounts (of baking soda or distilled water) and always have a test kit to measure the changes.

pH Levels

There’s an entire article on pH levels. But to quickly summarize, the pH measures your aquarium water’s acid level.

The scale goes from 0-14 and 7 is neutral (neither acidic or basic). 0-6 is acidic while 8-14 is basic.

If you need to change your pH level, consider your carbonate hardness level. The harder your water is in KH, the more difficult it’ll be to change because the pH will just bounce back. Conversely, the softer your water is in KH, the easier it’ll be to make changes.

Nitrogen Levels

The nitrogen levels relate to the amount of ammonia, nitrites, and nitrates in the water. The importance of these compounds is explained in the nitrogen cycle article.

The main concern here is that these nitrogen compounds are toxic to marine fish.

Phosphate Levels

The main concern of high phosphate levels is that it acts as a food source for algae and other planktons. Having high levels will result in green waters.

Normally, saltwater pH will not let phosphate dissolve in the water. However, if the pH drops, which can occur in a few days, the phosphate dissolves into your saltwater aquarium and becomes available to alge.

A pH below 8 will allow phosphates to dissolve. A pH around 8.5 will allow some phosphates to bind to walls and rocks. A pH above 9 will cause phosphates to crystallize and drop to the ground.

You want to have your phosphate level as close to zero as possible, around 0.1 ppm.

Chlorine / Chloramine Levels

Chlorine and chloramine is added to your water to disinfect it from organisms like amoebas that can cause diarrhea and other health problems.

Chlorine quickly breaks down and you can use chlorinated water just by leaving it alone for a few days.

Chloramine, however, is far more stable and will not break down. It is a combination of chlorine and ammonia, both which are highly toxic to fish. Chloramine will enter the bloodstream through the fish’s skin and block oxygen-carrying cells.

Chloramine will kill your entire aquarium tank of fish in 24 hours.

Cycling is the process of starting the nitrogen cycle. Because the process involves developing bacterial colonies, capable of converting highly toxic waste material to forms that can be used by plants or be purified, it takes time. Unless your fish is a hardy breed, they will not survive the process because they cannot handle the high levels of toxins. If you’re not familiar with the nitrogen cycle, you may want to read the article first before reading this one. This article will make a lot more sense if you do. One of the first things you’ll want to do is get a nitrogen test kit. They’re inexpensive and widely available at most pet or fish stores. With the kit, you’re going to check for the presence of ammonia, the nitrite, and finally nitrate. Once the nitrogen cycle is established, you should not see any ammonia or nitrites. If you see ammonia but no nitrites, you’ll know the bacteria that converts ammonia to nitrites are still colonizing your aquarium. If you see nitrites but no nitrates, you’ll know the bacteria that converts nitrites to nitrates haven’t developed. By the time you’re ready to cycle your aquarium tank, you should have your substrate in place. You probably don’t want to use a full tank. It takes longer to cycle and while you’re doing this, you may want to make changes. Using a 1/3 or 1/2 filled tank is optimal. Before cycling your tank, make sure your water quality is where you want it. A lot of cities add chemicals to the water supply so check the pH and the presence of copper (copper is deadly to invertebrates).

Natural Way

If you don’t have access to an established aquarium, you can put a few flakes of fish food every 12 hours. Once the food starts to decompose, it’ll release ammonia, which will attract your first class of bacteria. Once they convert the ammonia to nitrites, it’ll attract th second class of bacteria. Instead of fish food, you can drop in a small chunk of raw fish or shrimp. Use a 1 inch by 2 inch piece. Alternatively, you can use ammonia. Ammonia is commonly sold near the cleaning supplies in grocery stores. Make sure it’s pure ammonia and doesn’t have any additives like perfume or soap. Add about 5 drops per 10 gallon every day or until ammonia registers on your nitrogen test kit. Once you see detect nitrite, cut the dosage in half and continue until you detect nitrates. This entire process can take a week or two. Be patient.

Jumpstarting The Process

The quickest and cheapest method is to use an aquarium that’s already been established to introduce the necessary bacteria to your aquarium. All you really need is a small scoop of their substrate to introduce the necessary bacteria. These bacteria live in both freshwater and saltwater so it doesn’t matter what type of aquarium they come from. You can get a small sample from a friend who has their own aquarium or even your local pet store or fish shop (if you ask nicely). Actually, the filter material is a better source of the bacteria but the substrate is easier to obtain. Make sure the nitrogen cycle has been firmly established by feeding your aquarium fish flakes until you regularly detect nitrates.

Nitrogen Cycle Kits

There are a number of products that contain the necessary bacteria to seed your tank. Some even claim to do it in 24 hours but they’re also quite expensive. If you don’t want to wait and money is not a concern, use the nitrogen cycle kits.

Final Step

Although nitrates are far less toxic than nitrites or ammonia, it’s still toxic. Before adding fish, perform a 30% water change to reduce the nitrates. And your aquarium is fully cycled.

The nitrogen cycle that occurs in an aquarium tank is a small replica of what happens in the wild. Because the aquarium does not have all the elements of the wild, human intervention is required to maintain the ecosystem balance.

The Nitrogen Cycle Starts With The Fish

The nitrogen cycle starts with the introduction of fish in the aquarium tank and food. As the fish eats the food and uses the oxygen in the water to produce energy, the fish also produces waste material.

The waste material is made up of carbon dioxide and fecal matter. The fecal matter decomposes into nitrogen compounds such as ammonia. In order to maintain the delicate balance, the nitrogen and carbon dioxide must be removed somehow.

The carbon dioxide is mainly removed through 2 processes. The first is aeration or the contact between the water surface and air. Carbon dioxide is exuded into the air and oxygen mixes into the water. If you have live plants, they use carbon dioxide and nitrates (explained below) in photosynthesis and produce oxygen as their waste material.

Bacteria Break Down Ammonia And Nitrites

The ammonia is mainly reduced through bacteria called nitrifiers that reside in the sand, plant leaves, gravel, filter systems, or live rocks. One type of nitrifier (called nitrosomonas) converts ammonia into nitrite. Another type of nitrifier (called nitrobacter) converts nitrite to nitrate.

The first type of bacteria is introduced as soon as ammonia is present. The second type of bacteria is introduced as soon as nitrites are present.

Although all 3 nitrogen compounds are toxic to fishes (ammonia, nitrite, and nitrate), nitrate is significantly less toxic than the others. However, you still want to maintain your nitrate level down below 10 ppm (parts per million). In the wild, the nitrate levels are usually below 5 ppm.

Nitrate are the primary food for algae so if your tank has an algae problem, this usually indicates you have high nitrate levels. Some people purposely introduce macroalgae to temporarily lower nitrate levels.

In order for nitrifiers to convert nitrites to nitrates, they need an abundant source of oxygen (for a biochemical process called oxidation). However, if there’s low levels of oxygen then the reverse happens. The bacteria convert nitrates back to nitrites.

However, unless there’s a sudden increase in bacteria growth (called a bacteria bloom), oxygen levels are not normally a concern unless you’re overstocking your tank.

And finally, the nitrate is removed by your:

• Filtration system
• Changing water
• Live organisms that use photosynthesis (i.e. plants or corals)

Keeping Your Nitrifiers Happy

The bacteria in this cycle like having certain environments. The first is a stable pH level that doesn’t fluctuate too wildly, preferably between 7 – 8.5.

The nitrifiers also like a temperature range between 65 – 85. Again, reducing temperature fluctuations is more important than just keeping your temperature within this range.

Salinity (or salt conent of the water) is of little concern to the bacteria but they are sensitive to UV radiation. Fortunately, glass naturally screens out UV but acrylic does not.

Because of their light sensitivity, a favorite breeding ground of these bacteria is in the filtration system. They often form slimy colonies and healthy colonies have an earthy smell.

Starting The Nitrogen Cycle

There’s an entire section on starting the nitrogen cycle but one thing you do not want to do is start it with live fish. Most fish cannot endure the ammonia and nitrites while bacteria colonies develop.

Remember, nitrosomonas (converts ammonia to nitrites) only develop in the presence of ammonia. While they develop and build up their numbers, the fish is already being stressed by the presence of ammonia.

Then when the ammonia is finally starting to convert to nitrites, only then do the nitrosomonas start to develop. By the time enough nitrosomonas colonize and convert nitrites to nitrate, the fish would probably not have survived.

Substrate is a fancy word for what you put at the bottom of your aquarium like gravel, sand, or rocks. Some substrates are great for fish-only aquariums while others have benefits to both fish and plants. The purposes of substrate are:

• It helps the fish orient up and down. Since the top surface is naturally reflective, having a reflective bottom surface  confuses the fish and stresses them.
• It’s a great breeding ground for needed bacteria and other organisms.
• It’s a natural habitat for crabs, sea snails, and other bottom dwellers.
• It provides a nutrient-rich layer for live plants and a place to anchor.
• It gives a natural look to your aquarium.

Selecting the right substrate will go a long way to helping you maintain your aquarium’s delicate ecosystem. This ecosystem is an artificially balanced and needs your intervention to make sure it stays balanced.

How Much Substrate Do You Need?

In general, having about 2-2.5 inches is enough. Having more than that and you run the risk of excess food particles getting trapped in the depths where there’s less oxygenation. Then the food particles degenerate into hydrogen sulfide which is not only high toxic to the fish, it smells like rotten eggs.

In order to estimate how much substrate you need, measure the surface area of your tank (in inches) and divide by 20 to give you the pounds. For example, if your tank is 15″ x 25″, you’d need approximately 18.75 lbs. of substrate.

Neutral pH Substrates

These substrates do not affect the water pH of your aquarium at all.

Gravel

This is them most common substrate and the type varies from very coarse to very fine. It’s mainly made of quartz and is only suitable for either fish-only aquariums or the top layer of a 2 layer substrate for live plants. Gravel needs regular vacuuming to remove food particles that slip into the crevices.

Sand

Avoid sea or ocean sand (i.e. going to the beach and scoopingup some sand). The sand tends to contain a wider variety of organisms that you want and when they die (and they will die since your aquarium will not have everything they need to survive), their bodies will decompose, producing ammonia and making your water more acidic. But with that said, sand can make an excellent substrate. It tends to compact to prevent food particles from lodging between grains and sand is a natural habitat for bottom dwellers. However, you will need a good filtration system to remove food particles from the surface or you will need to perform regular vacuuming. Two sources of cheap sand are:

• Sandblasting sand (which is coarser than regular sand)
• Play sand (used in playgrounds)

One advantage of play sand is that it is sterilized for the protection of children.

Substrates That Raise pH

The following substrates will release a steady stream of buffers that will reduce water acidity and raise pH levels.

Crushed Coral

This has been a traditional favorite of aquarium owners throughout the world. Often a crushed coral mix is comprised of calcium-rich minerals like dolomite, calcite, or argonite. Because of the calcium content, it will buffer well and will push your pH up to 7.6 or so. However, pure crushed coral is coarse and it tends to trap debris (food particles and fish waste material mostly) which will result in overall more nitrates. Nitrates are toxic to fish. Also, crushed coral will harden over the years and after years or decades, it will cement together, making removing a big hassle.

Argonite

Argonite is a calcium carbonate mineral which slowly releases its calcium carbonate, buffering the pH and raising it up to 8.2. The released calcium is valuable for live coral as a source of building material.

Living Plant Friendly Substrates

The following substrates tend towards neutral pH but have benefits especially for live plants in your aquarium.

Laterite

Laterite does not contain any nutrients but has the ability to store and release nutrients for plants. It tends to be porous and makes good lower substrate for live plant aquariums. The cheapest form of laterite is cat litter but often, cat litter contains perfumes to hide urine odors and clumping agents to make cleaning convenient. Aquarium-grade laterite is sterilized and does not contain any additives.

Vermiculate

Vermiculate is a magnesium, iron,and alumnum mineral mixture that absorbs and releases phospates over time. It also converts ammonia to nitrates. Both nitrate and phospates are nutrients to plants. Like laterite, it makes a good lower substrate for plants but its tendency to compact makes it less than ideal. However, a combination of laterite and vermiculate resolves these issues and makes an excellent lower substrate for plants.

pH is the measure of acidity or base of water. As you can see, the pH scale goes from 0-14. 7 is neutral.

Anything that is pH 0-6 is acidic and anything pH 8-14 is basic.

The scale is logarithmic, meaning each division is 10 times more than the previous one. For example, a pH of 2 is 10 times more acidic than a pH of 3.

The reason the pH level is so important is that each species of fish has a certain range of pH which they can survive. If the pH goes outside this range or fluctuates too wildly, the fish will die.

The main concern of aquarium owners is the acidity of the water. Fish tend to have a lower tolerance to acidic waters than basic waters (although water too base will kill fish just as readily).

There’s a class of chemicals called buffers (calcium and carbonates) that will act as a buffer to the pH levels of your tank, making sure that the pH doesn’t fluctuate too quickly and absorbing excess chemicals that cause pH levels to shift.

Coincidentally, these same buffers are often used as antacids.

This is the first decision you have to make when setting up a marine or saltwater aquarium. This choice will have a significant impact on not only your choices later on but maintenance and care as well.

Size Matters

One of the first things to decide is the size of your tank. Buy the largest tank that you can either afford or will fit in your home or office. There’s a number of reasons for it like:

1. You’re less likely to outgrow your tank.
2. It’s easier to maintain a stable environment with larger tanks.
3. You have more options in fish, decorations, and plants.

The smallest tank you should consider is 30-40 gallons (approximately 115-150 liters). There’s a lot of stories of people starting with hobby tanks that later wished they bought bigger tanks.

Transplanting all their fish, rocks, gravel, and plants to a new tank is a lot of work. It’s also expensive to purchase new filters, lights, and everything that comes from setting up a new tank.

Did you know that saltwater contains 42% less oxygen than freshwater at the same temperature? Maintaining stable oxygen levels is far more critical in a saltwater tank than a freshwater tank. And as you might have guessed, animals die when they don’t have enough oxygen.

The primary way oxygen is introduced to the water and carbon dioxide is exuded is through the exchange that occurs between the water and air. The surface area between the air and water is absolutely vital in ensuring not only enough oxygen is present but to make sure waste products (i.e. carbon dioxide) is removed from the tank.

As a direct consequence of having stable oxygen supplies, you have a greater selection of fish for your aquarium

Tank Material

Some basic (and obvious) requirements for your saltwater aquarium tank are:

• Does not leak
• Is not toxic
• Is not water-soluable (tank material does not slowly melt into the water)
  

  Glass Aquarium Tank

You can choose whatever material you want but by sticking with either glass or acrylic aquarium tanks, you’ll sidestep a lot of these issues.

The choice is largely a preference. Here are the pros and cons of acrylic:

Pros:

1. Acrylic tanks insulates better than glass tanks. You’ll have smaller and slower temperature fluctuation. You can also use smaller heaters or chillers compared to a glass tank.
2. Acrylic tanks are clearer thank glass tanks. Acrylic lets 14% more light than glass.
3. Because glass is much denser than acrylic, acrylic tanks will be lighter than glass tanks.
4. Acrylic is much tougher than glass. It’ll take a much greater force to break an acrylic tank than a glass tank. You can drill holes to mount filters, chilers, or heaters with less effect on acrylic tanks.
5. Because of the relative brittleness of glass, they can’t be shaped in as many formations as acrylic. Acrylic tanks can be molded into almost any shape imaginable.

Cons:

1. Compared to glass, acrylic is highly scratchable. Even manufacturers, who use special packing material, will sometimes accidentally scratch their own tanks. If you’re having the tank moved, there’s a danger it’ll be scratched. Anyone walking by, jewelry, belt buckles, cell phones, almost anything will scratch acrylic tanks. When cleaning an acrylic tank, whether on the inside or outside, you need to use special pads to prevent scratching.
2. Because acrylic is lighter than glass, it cannot support its own weight and any stand you purchase needs to support the entire bottom of the acrylic tank. A glass tank can support its own weight and only needs support along the edges.
3. Glass maintains its clarity over time. Many acrylic tanks yellow with age when exposed to sunlight or a full spectrum lighting.
4. Acrylic tanks are more expensive than glass tanks. This isn’t necessarily due to one being better than another but the shipping cost of acrylic tanks, which scratch much easier than glass tanks.