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Baseline Tests

We're almost ready to start cycling the tank but, before we start, we need to get a water testing kit, get familiar with it and perform some initial tests to ensure things are as they should be.

We're going to use an API Saltwater Master Test Kit. This kit includes tests for pH, ammonia, nitrite and nitrate. We have not discussed these parameters yet, but we'll talk about them in more detail when we start cycling the tank. For now, we just need to learn how the tests work.

Although API test kits have a bad reputation on some forums, I have used them to cycle several tanks and not only are they very well suited for that purpose but they also provide more accurate results for nitrate than some of the competitors.

All of these tests involve the following:

  1. Put a sample of the tank's water in a vial
  2. Add one or more reagents
  3. Mix
  4. Wait
  5. Compare the color of the resulting liquid with a color chart

Always read the instructions for each test carefully before you begin. API provides an instruction manual for this test kit online.

We're going to start by walking through a pH test.

pH Test

Get the Sample Water

1) Fill a clean test tube with 5 ml of water to be tested (to the line on the tube).

This is where we run into a small downside with this test kit: it doesn't include a pipette to draw the sample water from the tank. They expect us to dip the test tube in the tank, which is not the best idea since the test tube could be dirty. So, it may be worth buying some pipettes.

We're going to use the pipette that came with the refractometer to draw some water from the tank and then drop it into the test tube until it reaches the 5ml mark.

And now we need to learn about the meniscus which is the curve formed by a liquid in a tube. If you look closely at the surface of the water in the test tube, you will see that it is curved. We need to get it so that the bottom of the curve is on the 5 ml line as you see in the picture.

Add Reagent

2) Add 5 drops of High Range pH Test Solution, holding dropper bottle upside down in a completely vertical position to assure uniformity of drops.

So, we get the bottle of solution and add 5 drops as directed.


3) Cap the test tube & invert tube several times to mix solution.

Grab a cap from the kit and do just that. It's best to put a little bit of pressure on the cap with your finger so that it doesn't leak.

Read the Result

The pH test doesn't require time to develop: the results can be read immediately.

4) Read the test results by comparing the color of the solution to the High Range pH Color Chart. The tube should be viewed in a well-lit area against the white area of the chart. The closest match indicates the pH of the water sample. Rinse the test tube with clean water after use.

This is where things can get a bit fuzzy. It can be difficult to match the colors. But here are a some tips:

  • If possible, do your tests during the day so you have daylight to view the colors. It's also a good idea to do them at around the same time each day.

  • Pick a spot next to a window where you will take your test result and color chart and attempt to match them. I always use the same spot and I lay the color chart and the tube on the same window sill.

  • Squinting your eyes may make it easier to match the colors.

  • If you're having trouble making a decision on the best match, ask someone else to come look and give you their opinion.

Here is a picture of my pH test result:

It is as expected and looks most like 8.0 to me which is a great starting point.

After you're done with the test, pour the liquid down the drain and rinse the test tube, cap and pipette, preferrably with RO/DI water. Leave the test tube uncapped so that it will dry. Keeping things clean is important when testing.

About pH

Let's take a moment to talk about pH. The ideal pH range for a saltwater tank is between 8.0 to 8.4. That being said, there is no real harm in pH as low as 7.7. pH changes throughout the day, so it is important to test at the same time every day.

One of my tanks has a pH probe and the pH swings between 7.9 and 8.2 every day.

If your test result does not match the color chart, or matches 7.4 or 8.8, you may need to take action to correct it before you go on. This is unlikely, so we won't discuss possible solutions here.

Testing Ammonia, Nitrite and Nitrate

These are the parameters that we will be watching closely while we cycle the tank. We'll discuss them in more detail in the next article. For now, we should perform an initial set of tests to make sure we have a good starting point.

Our water should have no ammonia, nitrite or nitrate right now, but we need to confirm this.

I'll let you run the three tests on your own. Just make sure you follow the instructions closely and pay attention to the reagent amounts and the mixing and wait times. All three tests requires a 5 minute wait which is best done by setting a timer.

You can start by filling the three test tubes at the same time, but it's best to conduct each test separately so there's less risk of a mix-up.

Pay special attention to the mixing requirements for the Nitrate test.

Always cap the solution bottles right after you use each one, so there's less chance of a spill.


Here's what my ammonia test result looked like:

Surprise! The color of the solution doesn't match any of the colors of the chart, which is common for this API test kit. That being said, it doesn't seem to have any of the green colors that show ammonia above zero so we can safely call this zero ammonia. When ammonia shows up in the amounts we expect, the result will definitely end up green: we should see that once our cycle gets going.


This result looks much better: we can definitely see that there is zero nitrite in our water as we expected.


The picture is terrible and this is one test that requires good light to be able to distinguish the subtle change from yellow to orange, but we can safely say that we have zero nitrate in our water as we expected.

Not Zero?

If your tests yielded measurable amounts of ammonia, nitrite or nitrate, there may be some cause for concern. It is possible that the sand or rocks had decaying matter that added ammonia or that your source water already contains nitrite or nitrate. Do some research on how to address this now so that it doesn't interfere with the cycle. Definitely take some action to fix it or at least find the cause.

We've learned about testing and we're now ready to start cycling the tank.