Category Archives: Coral Care

The Right Alkalinity For Coral Growth

One of the number one challenges faced by new reef keepers is trying to determine how much alkalinity is best to keep their coral healthy and growing.

Soft corals such as zoanthids and leathers, and long polyp stony corals such as favia and lobophyllias can be pretty forgiving when it comes to alkalinity levels.

But acropora and most other short polyp stony corals are another story…

They require a very stable, consistent level of alkalinity – which brings about one of the BIG questions new reef keepers (like me) often ask…

What is the best alkalinity level for growing coral?

The most common and ‘correct’ answer is:  it depends on the lighting and nutrient levels in your tank.

For quite some time now I’ve struggled to figure out just what exactly that meant. Does it mean more light and zero nutrients? Less light and more nutrients?

It gave me no understanding of light, phosphates, and nitrates related to finding the best alkalinity level for keeping my coral healthy and growing.

Then I saw this information in a post on my local forum and I knew I had to share it.

Once I read it, everything finally started to make sense.

This information is courtesy of the members of the Washington Area Marine Aquarists Society.

1. Keeping your alkalinity STABLE is crucial

The most important part of keeping acropora and other SPS coral is ensuring your alkalinity remains consistent.

As long as your alkalinity remains stable at one set value somewhere between 6 and 11 dKH your coral will be fine.

If it bounces up and down a lot within that range though, the constant change will shock your coral and eventually weaken or kill it.

Now, let’s figure out what value in between 6 – 11 dkH would be a good starting point for determining the best alkalinity level for your tank.

2. There is a correlation between alkalinity, light, and nutrients.

Most corals – particularly acropora and SPS corals – contain photosynthetic algae, called zooxanthellae. It acts as a sunscreen and is what gives them their color.

Phosphates and nitrates – aka ‘nutrients’ – act as food for the zooxanthellae. To much food will mean too much zooxanthellae or  ‘sunscreen’. Not enough food will mean not enough zooanthellae or sunscreen.

So, if you have your alk in the 6 and 7 range, your nitrates and phosphates need to be low so you don’t stunt growth.

Less than 0.03 ppm phosphates and 5 ppm nitrates would be a good place to start. Then, if needed you can slowly lower them even more.

On the other hand,  if you keep your alk in the 11-12 range, you need to keep your nitrates and phosphates much higher so the zooxanthellae can keep up and protect the acro.

A lot of time you see acros with “Burnt tips”.  This occurs because the zooxanthellae algae can’t keep up with the coral growth.  Eventually if the zooxanthellae gets further and further away from the tips, they will die halting growth.

Here is an example of alkalinity at a level that is right on the edge of being too high in relation to nutrient levels:

nutrients almost too low for alkalinity
This person is skirting the line of trying to keep nutrients low while maximizing growth – causing pastel colors on the growth tips…

And this is what happens when it is too high – burnt tips.

alkalinity is too high
The flesh not only burnt away leaving the tips white, it left the underlying skeleton exposed to algae growth.
3. Zero in on the best alkalinity level for your tank

With that in mind you can now zero in on the best alkalinity and nutrient levels for your tank.

Let’s say your nutrient levels are high – for example, your phosphate is ~0.15 dKH and your nitrates are ~15 ppm.  If your alkalinity is below 9 dKH, you may want very slowly raise it until you see the kind of coral growth and coloration you like most.

OR, you can gradually lower your nutrient levels until they are more in balance with your current alkalinity level.

Likewise, if your nutrient levels are low – say your phosphate is below 0.03 ppm and your nitrates are less than 5 ppm, you can lower your alk… OR you can raise your nutrients.

Either way, the key is make the changes slowly. And, once you find the alkalinity level that gives you the coral growth and color you desire, make sure it remains as stable as possible.

In the end, every aquarium is unique and you will have to find the right level for your tank.

But this information is a great place to start.

How to Dip Corals – 5 Simple Steps

You should always dip corals before placing them into your aquarium – it’s not only easy to do but also vital to the health of your aquarium – for several reasons. Here are just a few:

  • It removes unwanted and dangerous pests from your new coral. It is no fun to spend $50, $100, or more on a new piece of coral only to discover a few days later that some hitchhiking red bugs… acropora-eating flatworms… or soft coral eating-nudibranches are chowing down on your precious new gem.
  • It protects your existing corals:  It’s even less fun to discover a few weeks later that those hitchhiking pests have spread throughout your tank and are also nibbling away at several of your other beautiful corals.
  • It refreshes and helps heal new coral after the stress of fragging, shipping, etc. In addition to removing most unwanted pests, a good coral dip also helps to sanitize and irritation or wounds the coral may have suffered – helping to reduce the chance of infection while your new coral acclimates to your tank.

If you’ve never tried to dip corals before, don’t worry – it’s very easy and can be done in five simple steps…

Step 1:  Select a Coral Dip

There are several coral dips available to the saltwater aquarist, three of the most popular are Bayer Advanced insecticide, Coral Rx, and Coral Revive.  And a fourth that is fairly new and just starting to make some inroads into the hobby is ME Coral Wash Off dip. Here is a quick look at each:

  • Bayer Advanced insecticide – yes, this is the insecticide you can find at stores such as Home Depot or Lowes. Many people have great success with it. Bear in mind though, it is an insecticide – if you do not dip properly and rinse really well – there is the potential for trace amounts of the nerve-agent chemical it contains – imidacloprid – to be absorbed by fish and other tank inhabitants. The risk is probably small and MANY people use it – here’s a great write-up on it by Cherry Corals.
  • Coral Rx – probably the most popular off-the-shelf coral dip made specifically for treating corals.
  • Coral Revive – another popular off the shelf coral dip.
  • ME Coral Wash Off – an new up-and-comer. Like the other two brands mentioned, it relies on  in relies on lemon and pine oils as its primary active ingredients. However, unlike the others, it also contains lavender oil – and it’s concentration of all 3 oils is slightly higher than the others.

I chose to use ME Coral Wash Off and have not yet tried any of the others.

Once you have your chosen dip in hand, it’s time for the next step.

Step 2: Prepare to Your Dip Corals

Things will go much quicker if you have everything prepped and on hand before you begin to dip corals. This is a list of items you’ll need:

  • Your chosen dip – my case it is the ME Coral Wash Off 4x (they also make a 2x – which is half the concentration)
  • At least two containers – one for the dip and one for the rinse
  • A pair of gloves
  • Safety glasses
  • An old hand towel
  • A magnifying glass

And here are a few optional items I also find it very handy to have

  • An empty 12″ x 9″ container
  • A coral tool
  • And a turkey baster
  • A glue removal tool
  • AND, if your display tank is small like mine, a gallon or two of fresh saltwater

By the way, I use cheap Glad food storage containers for my dipping.

And yes, I highly recommend using gloves and safety glasses when you are going to dip corals.  Regardless of which dip you choose, you are going to be working with pesticide and/or pharmaceutical grade essential oils. Neither is something your skin really needs – let alone your eyes if it should happen to splash. Oh, and remember some corals – such as zoanthids and palythoas – contain toxins.

Here’s a quick shot of my setup:

the setup I use to dip corals
Counter-clockwise from top right: dipping container, rinse container, glue rinse container, big empty container, bottle of coral dip, turkey baster.

Step 3: Dip Corals and Observe

Mix up your dipping solution per the instructions on your dip.

In this case, the ME Coral Wash Off 4x calls for 15 drops mixed into 1L (~32 oz) of saltwater. So I took a quart of saltwater out of my display tank (DT) and poured it into my dipping container (top right of pic)… added 15 drops of Wash Off… and mixed it with the turkey baster. Then, since my DT is small (24g), I poured a quart of freshly mixed saltwater back into it to replace what I had taken – otherwise my automatic top-off would put a quart of RODI water into the tank to replace the lost volume and end lowering my salinity.

Fill your rinse container.

I took another quart of water from my DT and poured it into my rinse container – and poured a second quart of fresh saltwater into my DT to once again replace what I had taken.

Since I was also going to be super-gluing the new coral frags onto live rock in my DT, I put about an inch of fresh saltwater into the third round container pictured (far left) to use as a ‘glue rinse’. More on this in a moment…

Place your coral frags into the dip and let them soak in it for the amount of time called for in your chosen dip’s instructions.

ME Coral Wash Off calls for 5-10 minutes so I left them in for ten. During that time I basted them with the turkey baster to help flush off any pests or dirt. If you don’t have a turkey baster you can also hold each frag and, one at a time, gently swish them a bit with your hand.

While they’re soaking use a magnifying glass to do a very thorough visual inspection for any unwanted pests, critters, or they’re eggs. You may need to use the turkey baster or a tool to very gently flush or scrape them off if the wash alone isn’t enough.

corals soaking in coral dip
A turkey baster can be used to gently flush each coral while it is soaking in the dip.

Step 4: Rinse

Once the soak time is up, take them out of the dip and place them in the rinse.  Use the turkey baster or your hands to give each a gentle flush or swish to ensure the dip is thoroughly rinsed off.

Your corals are now ready to placed either a coral quarantine tank or your display tank depending on your own personal comfort level.

Step 5: Place

That’s it – you know now how to dip corals.

Wait a minute, what about the glue tool and big empty container you ask?

Well, I don’t have the room in my townhouse for a dedicated coral quarantine tank. And my display tank does not have thousands of dollars of coral or livestock in it. So, I put my corals straight into my DT after dipping (All the more reason to dip! At least it offers some level of safety.)  That’s where the big rectangular container and glue removal tool come into play…

coral ready to be removed from plug
Cyphastrea coral has been dipped, rinsed, and is ready to be removed from the frag plug.


coral glue removal tool
Coral glue removal tool

I prefer to remove my coral from the frag plugs whenever possible. Any pests or algae the may still be on the plug will end up in the tank. And I think the tank just looks better without them.

I simply place the coral frag in the container and hold it steady with one hand. Then I place the edge of the tool at the seam where the glue meets the frag plug and apply firm,gentle pressure. The coral usually pops right off and the container catches any little bits of glue that crumble off.

You can see I’ve marked the container ‘dry only’. Sometimes a plug is a little stubborn – and when its glue final does give, the tool thwacks the bottom of the thin plastic container. It may make a pin-hole puncture in the bottom. So I marked it so I’ll be sure to never use it to hold any water for dipping, etc., just to be safe.

A dollop of crazy glue on the bottom of coral… a quick dip of just the glue dollop in the ‘glue rinse’ (when crazy glue first hits water a little sheet of film comes off it. I prefer not to have it floating around the water surface of my DT, hence the quick dip in the ‘glue rinse’ water.)… and into the tank the coral goes.