Category Archives: Saltwater

Dosing Phytoplankton: Is It Good for Your Aquarium?

Dosing phytoplankton can provide many benefits for some aquariums, and yet may cause problems for others.

Determining whether or not it’s a good idea to use it can often be difficult.

And a quick look on popular saltwater aquarium forums reveals quite a raging debate.

Some folks argue phytoplankton is the foundation of the food chain in our oceans, and is therefore beneficial to life in a reef tank.

Others say it can’t be directly consumed by coral or most other aquarium inhabitants … and therefore does nothing except to add unneeded nutrients to the water.

I’ve tried dosing phytoplankton in my 24-gallon mixed reef aquarium on two different occasions. Each spanned one month.

The only change I noticed the first time was an decrease in the time it took for film algae to grow on the glass. Before dosing phytoplankton I had to clean my glass once every 4 days.

After I began dosing phyto, I had to clean it every 3 days.

Bottle of Phytoplankton

There were no changes in coral growth or color. And no other noticeable changes, so I stopped dosing it.

Over-filtration  in the months that followed caused my water to become a bit too ‘clean’. I noticed slower growth and paler color in some of my corals. So, instead of running a skimmer and filter floss together, I decided to use just the skimmer.

After a couple of months my nutrients were still measuring in a nice, low acceptable range: 0.01 phosphates and less than 3 ppm of nitrate.

But there was still just enough of an increase in each for my corals to regain their vibrancy and grow a bit quicker. They were consuming the extra nutrients before they could cause my measured values to rise.

Now, you’re probably wondering, “what does this have to do with dosing phytoplankton?”

Well, I also noticed another unexpected surprise. New sponges began to grow on my live rock.

When I first set up my tank, I used live rock from Tampa Bay Saltwater. It was COVERED in barnacles, sponges, and other life.

Unfortunately, as my tank matured, and my nutrient levels came down into proper ranges, they slowly died off and faded away.

When I saw these new sponges starting to appear, I thought dosing phytoplankton might help them to spread even more.

So tried dosing phyto for a second time.

The result?

The same as the first time. I’ve had to clean film algae off my glass twice as often. But I’ve noticed no difference in the growth rate of the sponges or anything else.

So I’ve stopped dosing it. And I doubt I’ll try it again.

It is apparent to me now that my tank does not have enough phytoplankton-dependent life in it any more to make it worthwhile. The nutrients from uneaten fish food, fish poop combined with twice-weekly feeding of coral food is enough to keep my tank happy.

However, I do wish I had known about dosing phytoplankton when I had first set up my tank with that live rock.

All those original barnacles, sponges, porcelain crabs, and the myriad of other filter feeders would probably still be alive and thriving if I had started dosing phyto then.

That is perhaps the biggest key to knowing if it’s worth dosing phytoplankton in your tank.

If you have a lot of filter-feeding critters in your tank, it is definitely worth giving it a try.

On the other hand, if you only have a few, or none, then dosing phyto probably isn’t worth it. You will only be wasting money and adding unnecessary nutrients to your tank.


Nyos Reefer Calcium Test Kit Review – This Kit Could Spell Trouble…

The Nyos Reefer Calcium test kit is relatively new to the U.S. aquarium scene.

I had been using Salifert’s calcium test kit. But, since Nyos positions its kits as being ‘high precision’ test kits, I decided to give it try.

Nyos Calcium Test Kit
Nyos Reefer Calcium Test Kit

The very first thing I noticed when I opened the Nyos kit is that the syringes looked to be of higher quality than those in the Salifert kit. So did the bottles the testing reagents were in.

At first this kind of impressed me. But it actually turned out to a bit of a problem.

The test is simple enough…

  1. Use the green syringe to add 4ml of aquarium water to the test vial.
  2. Add 10 drops of the first reagent (CA-1) to the vial, then swirl the vial for 5 seconds.
  3. Use the included measuring spoon to add one level scoop of the second reagent (CA-2) to the vial. (The water turns red.)
  4. Place the dropper tip on the black syringe, and draw 1ml of the third reagent (CA-3) into the syringe.
  5. Then, drop-by-drop add it while swirling the vial. Continue adding it drop-by-drop until the solution turns blue.
  6. Read the syringe to see how much was used. Each mark (0.01ml) equals 5ppm of calcium.

So, if the syringe still has 0.14ml left in it, then 0.86ml was used. 0.84×5=4.30 or 430ppm of calcium in your water.

But this is where the problem of the high quality syringe gave me trouble…

The syringe in my test kit has very good seal on its plunger. So good that it takes quite a bit of finger pressure to dispense the fluid. And this makes it incredible difficult to dispense just one drop at a time.

The slightest bit of additional push to overcome the tight plunger results in several drops squirting out at once.

If it happens when the solution is close to turning blue, you can very easily end up having several extra drops squirt out leaving you with an inaccurate reading.

That brings us the second issue I’ve encountered with this calcium test kit – it almost always reads about 50ppm too high.

At first I wasn’t sure if my Nyos kit was reading high, or my Salifert kit was reading low.

Fortunately, I use a 3-part salt mix that I can very precisely measure out. And the manufacture labels what the exact salinity, alkalinity, and calcium values will be for those values.

Using scale and measuring cup I precisely measured out my salt mix components and water to make one gallon of fresh saltwater with a known calcium value.

When I tested this ‘control’ of fresh saltwater it read 50ppm higher than the manufacturer’s listed value.

When I tested the ‘control’ of fresh salwater with the Salifert kit it read dead-on with the manufacturer’s listed value.

And when I tested my aquarium earlier several times with each kit, the Nyos kit consistently gave me readings the were about 50ppm higher than the Salifert readings.

Conclusion: My Nyos kit tends to read about 50ppm high. My Salifert kit tends to be spot on.

Granted this may just be my particular kit. Maybe one of the reagents is old or bad. And since it is consistently high by 50ppm, I could reliably use it and just subtract 50ppm each time I test to get the actual tank reading.

But the sticky syringe just frustrates me too much to want to deal with it.

I may LOVE the Nyos Reefer nitrate test kit far more than any other I’ve tried..

But when it comes to calcium, I’ll stick with the Salifert Ca test kit.



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.