How to Raise Phosphate in a Reef Tank

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Keeping things like corals in a reef tank requires trace amounts of phosphates in the water where they reside. And, in the cases of a new tank, phosphates must be appropriate so you can start experimenting with your own aquaria. So, it’s likely you’re looking to boost your aquarium’s phosphates if you’ve found this article.

To have a healthy aquarium, it must have the appropriate amount of minerals. Phosphate is one of these. If you can’t keep the phosphate at proper levels through feeding fish and corals, then you’ll have to inject some into the tank. You can try overfeeding your fish, adding Activated Carbon into the tank or directly dosing the phosphate into the water.

Why would you need to raise phosphates in a reef tank?

If your aquarium is new or it exports nutrients too well, you have to increase the phosphate levels. This could be due to your coral eating up any available phosphate. Or, it could be because your system doesn’t have a stable enough nitrogen cycle. Whatever is causing the phosphate levels to be low, it will be crucial to have them at the right level.

How do you raise phosphates in a reef tank?

There are three surefire ways to raise phosphate in a reef tank. You can attempt to overfeed, add some Activated Charcoal or purchase a phosphate powder. Any of these methods will work but all of them have some pitfalls. This is because high phosphate comes with its own set of problems.

What’s more, use the Redfield Ratio to help with the phosphate levels perfect for your tank. This will help you maintain the best balance of all the nutrients.

Increase Phosphates with Overfeeding

If the phosphate levels are so low that you have to do something right away, then try to add more food into the tank. But, you’ll want to monitor this closely. For a whole day’s worth of feeding, only begin with a tiny bit at first. Check the levels to ensure pH balance, nitrates or ammonia aren’t getting out of control.

Stop the moment you think it’s getting too high. When in doubt, cease adding food and continue checking the levels. Note that this method is not something you’re going to want to do for the long haul. But, it does work in a pinch or if phosphate occasionally gets low.

Try Activated Carbon

Activated Carbon is great for most reef aquariums because it cleans unwanted organics while working together with your filtration system. This helps keep the tank free of debris while seeping phosphate into the water. This also reduces the need for frequent water changes.

Too much organic waste and overuse of Activated Carbon is often the culprit for high phosphate levels in an aquarium. But, if you’re struggling to maintain a stasis level of phosphate in your tank, you can try adding some Activated Charcoal to see if it helps.

Use Powdered Phosphates

Phosphates purchased from the aquarium store will come in a powder form. Something like Tri-Sodium Phosphate (See Amazon) works wonders. You can get this already diluted with reverse osmosis water (RO water) or obtain your own RO water from your sink.

If you mix the powder yourself, it must be RO water. Also, you only need to use a small amount of powder, even if you have a large tank. When using Tri-Sodium Phosphate, measure out 1.88 grams with a scale. Then mix the measured phosphate powder with one liter of water.

Then, for every 100 liters of aquarium water, add about one milliliter of the mixture. This should raise phosphates up to 0.01ppm (parts per million). Use this as a base to start from and continually check the phosphate levels. If it isn’t enough, you may have to double the phosphate to 3.76 grams for every 100 liters of water.

How do you know when you’ve added too much or too little?

If your tank is completely bereft of phosphate, it may take some time before you see any results. If there are any corals present, they will consume a lot at first. Consider the fact that if your corals don’t have enough phosphate to thrive on, your tank will suffer too. Since corals are alive, they’re going to consume any available phosphate first.

But, you don’t want to overdo it. Pour the diluted phosphate into the water with miniscule increments. This will help avert additional issues. Remember, the amount of phosphate in most saltwater settings is about 0.02-0.05ppm. So, you’ll want to reach this as close as possible.

Ensure you write down how much you add every time. This is so when the levels become readable, you’ll know how much you need if it ever happens again.

What are the benefits to raising phosphates in a reef tank?

There’s a lot of good you can do for your tank by adding phosphate when it’s too low. Some of these are:

You will have very happy fish, including plants, anemones and corals

You have complete regulation of the aquarium’s nutrients and minerals; you can achieve and maintain any level
It will increase nitrates and give the potential to export these more efficiently
It’s inexpensive to do; one small container of the powder should last for years

What are the dangers of raising phosphates in a reef tank?

Of course, quick spikes in phosphate levels can present several dangers that you really want to avoid. If you aren’t careful, any one of the following could happen:

Dissolved solids will surge when phosphates increase and things like ammonia, nitrates and pH balance can get out of control
Plentitudes of phosphates can turn the water yellow and make it difficult to see inside the tank

Phosphate has the capability to encourage unwanted algae blooms and this can grow at an alarming rate
Resulting algae blooms from too much phosphate can cause the coral to turn brown
High levels of phosphate can restrict the calcium carbonate necessary for the development of the coral’s skeleton

Final Notes

When phosphates are low in your tank, for whatever reason, it’s important to raise them to a good level as soon as possible. So, if you’re in an emergency situation, you can try overfeeding your fish. This is ok if your tank is low only once and awhile too. Regardless, you should find a better method of administering phosphates that will be easier to control.

Therefore, using Activated Charcoal or Phosphate Powder will be better if low levels are a constant problem. Even with this, you should watch your tank’s nutrient levels with meticulousness. Any serious spike can lead to several unwanted issues.

But, every tank will be different. So, use your best judgment and be as careful as you can. Once you get the hang of this, you will quickly learn what your tank needs and how to best control the phosphate levels.