(upbeat music) hello folks, robert from marine depot here and thanks for tuning in. Keeping nitrates under control has always been a concern for aquarias because it is the end product of nitrification and is continually produced by the bacteria inside of your tank.
For many it may seem like a constant battle to keep nitrate under control, but the good new is there are many proven ways to minimize nitrate build up, so here's what you need to know to take control of nitrates in your reef tank.
First, let's talk about how nitrate affects your tank's inhabitants. Nearly all scientific research about the effects of nitrate in an aquarium has been conducted with fresh water fish and inverts.
This research can really not be applied to salt water fish and inverts, especially corals. What little information that is available seems to indicate that nitrate is really not all that harmful, at least when compared to ammonia and nitrite.
Studies performed with reef building corals, perieties, and montastria demonstrated that nitrate levels as low as 0.3 ppm stimulated zooxanthelae growth within the coral tissue. This resulted in slower coral growth, presumably due to the algae out-competing the coral for rebuilding carbonates.
Another study using acropora indicated that nitrate didn't affect coral growth at all. A study on pink shrimp concluded that nitrates should be kept below 200 ppm. From this, we can conclude that the sensitivity to nitrate is really species specific.
Nitrate is not a deadly killer of corals but long-term elevated nitrates can inhibit certain corals from growing at full potential.
There is however, another more concrete reason to keep an eye on nitrate levels. Nitrate can stimulate algae growth. Nitrate is a great water quality indicator because as nitrate rises, so do other organic compounds that will contribute to algae growth and negatively impact your fish and corals.
The recommended nitrate level inside of a reef tank can be really confusing. You'll likely get a different answer depending on who you talk to or what you read.
The facts are nitrate levels on a wild reef, in the ocean, is below 0.1 ppm. If we make this benchmark nitrate levels should always measure zero using home aquarium test kits.
Our captive reef tanks, however, are drastically different than a wild reef. Considering that many successful reef aquariums keep beautiful thriving corals with nitrate levels above 10 ppm. So, the general idea for reef aquariums is to keep your nitrate levels low as possible without stressing over a specific number.
Keeping nitrates at 2 ppm or less, seems to be the norm. The most convenient way to keep track of nitrate is with a home water test kit.
The key to obtaining accurate results is to follow the instruction exactly as written. Mail-in water test kits are also another option for testing nitrates. It does take more time to get the results, but you'll also get a full analysis of you aquarium water along with it.
So now that we know a little bit more about nitrates in general, let's move on to how to control them. Water changes are great for diluting organics and rebalancing salt and trace elements but they do not work so well for controlling nitrate.
The difficult 10- 20% water change, even if performed weekly, will never be able to significantly reduce nitrate. This is because nitrate is constantly being produced by the bacteria in your aquarium that processes food and fish waste.
The dilution factor with the water change is simply not strong enough to make a dent in nitrate levels and there are certainly more effective ways to remove nitrate with less effort.
As with most aspects of aquarium keeping if the water you used to make salt water and top off your tank contains nitrate you're making things worse. You can avoid this problem with a high-quality reverse osmosis system such as the marine depot clean water units.
Our " o" systems will remove nitrate and a long list of other contaminates you don't want to add to your reef tank. It's the same with stocking levels and fish food.
The more fish and food that you add to the aquarium, the more nitrates will be produced. Feeding and stocking is fun, but too much will certainly get you into trouble fast.
This is the exact reason that when keeping a reef tank with corals, it is a good practice to minimize the fish and strictly adhere to proper feeding techniques. Biological nitrate control is an important foundation for any salt-water aquarium. the process is simple, bacteria convert nitrates to nitrogen gases through a process called denitrification via anaerobic bacteria.
It happens naturally in tanks containing live rock. The tiny crevices and pores are the ideal location for denitrifying bacteria that require low oxygen conditions. In many reef tanks this is all that is needed to keep nitrates under control.
Along side an appropriate stocking level and maintenance routine. In situations where nitrates are consistently elevated alternative methods of nitrate control can be employed.
Liquid nitrate removers in their many formulations take advantage of beneficial bacteria in a special way. They provide carbon that fuels the growth of denitrifying bacteria and when anaerobic bacteria is growing at accelerated rates, even more nitrate will be converted and removed from your aquarium water.
Liquid carbon can also force other types of nitrogen using bacteria to proliferate. These nitrate fixing bacteria can then be removed via protein skimmers. Protein skimming will strip out the nitrogen rich bacteria from the water ultimately reducing nitrates. this process of dosing liquid carbon into your aquarium is often referred to as carbon dosing.
Red sea nopox, brightwell aquatics reef biofuel, and even vodka, are all examples of carbon dosing. Think of a refugium as a mini aquarium tucked under your main tank.
It can simply hold more live rock for biological denitrification, but will typically also house macro algae with the appropriate lighting to support it. Macro algae uses nitrogen for growth and therefore when grown in a refugium, nitrate will be removed from the water as the algae grows.
When algae is harvested from the refugium the nitrate comes with it. This same principal applies to algae reactors such as the paxbellum units. Macro algae grows inside of the reactor, consuming the nitrates as it grows.
Algae scrubbers operate on a similar concept but rely on a different type of algae. Water flows through colonies of micro algae that are corralled inside a scrubber chamber. The micro algae remove nitrate incorporating it into their cells.
It's important to then periodically harvest the algae to physically remove the nitrogen from the aquarium. Nitrate removal medias come in different forms. Classically these medias rely on biological activity to consume nitrates, but recently, blue life has presented us with a regeneratable resin that specifically targets nitrates and nitrates only.
Biological nitrate removers are made from porous, ceramic like materials. The porous structure's rough surface provides an environment suitable for denitrifying bacteria. You can think of this media as tiny live rock.
It is typically placed inside of a media bag or inside of a reactor. Keep in mind it can take weeks or even months for the bacteria to colonize the media and start reducing your nitrates.
Biopellets are a solid form of organic carbon designed to slowly feed denitrifying bacteria inside of a reactor. The pellets provide a food source and a place for the bacteria to grow.
The pellets are tumbled heavily to constantly slough the bacteria growth which then exits the reactor and is removed via protein skimmer. This method is similar to carbon dosing but is done inside a reactor.
Proper water flow through the reactor and a very efficient protein skimmer are crucial for this method to be effective. Nitrate removal resin is a recent advancement thanks to nitrate fx from blue life usa which specifically absorbs nitrate from your aquarium water.
The media can be expensive when used for constant nitrate control, but it can also be regenerated for multiple uses which helps combat the higher price. Regeneration is simple and involves soaking the media in a sodium chloride solution.
The media is very tiny, so it is important to contain it inside of a media bag so you don't accidentally release the tiny beads into your display.
A sulfur denitrator is a recirculating reactor that houses a bed of sulfur media, below a bed of calcium carbonate media. By creating an anaerobic chamber inside of the sulfur denitrator, a colony of nitrate consuming bacteria is established on the sulfur media.
The bacteria converts sulfur into sulfate and nitrates into nitrogen gas. At the same time, hydrogen gas and co2 gas are also produced which then lowers the ph of the water inside of the reactor.
To help offset the drop in ph, a layer of calcium media is placed above the sulfur media, which will help increase the ph and also enrich the water with calcium and carbonates before it exits the reactor.
These sulfur denitrators can be really useful for heavily stocked aquariums where extremely high nitrates are always a threat. The concept was originally designed for waste water treatment, and once established, required minimal adjustments.
The only maintenance is the periodic replenishment of media and cleaning of the reactor. Determining the nitrate control methods that are best for you are all about you and your tank.
The first priority for all aquariums is prevention. Insure that you're using pure ro/di water, do not over-feed or allow leftover food to enter your filtration, and of course maintain your filtration system. When nitrates are continually a problem, only then would you want to consider additional control methods.
I have seen many tanks running successfully on only live rock, and i've also seen tanks running a larger refugium, algae scrubber, and biopellets all at the same time.
Also, be patient. Many of these methods require time to become established and start reducing your nitrate. Something somewhat important to understand about biological denitrification is that the presence of phosphate is required for most of these methods to work.
Bacteria and algae are living organisms that require carbon, nitrogen, and phosphorus in order to survive. The lack of any one of these elements can limit the amount of denitrification that occurs.
For example, as macro algae grows it consumes nitrates but also phosphate along with it. Once the available phosphate runs out the algae cannot grow and will no longer remove nitrates.
The same case applies to beneficial bacteria. This case is rare in aquariums, but is certainly something to consider if you're having trouble establishing biological denitrification or growing nitrate fixing algae. We have an excellent video all about phosphate control and you can find a direct link in the video description below.
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