How to read the "in betweens" while testing water.

[Stacie H.]

Hi,

My ongoing cycling saga may be improving a bit. I did a small PWC a couple of days ago (less than 10% out of a 36 gal tank). That was the first change I'd done in almost 2 weeks.

Today my levels were:

Nitrite= 0
pH=0

The hard part was reading the nitrate and ammonia...especially the nitrate! The ammonia was almost the color of 0.25 on the card, but not quite. The nitrate was a deeper yellow than 0, but no where NEAR the orange of 0.5.

I have the API freshwater master test kit. I guess it depends on the test, but I've seen folk posting levels of 1.0 for both. How can you tell? Is it a guessing game?

I'd set some water out today to do another small PWC, but opted instead to just top the tank off. Is this correct? It seems I should let things be and let the bacteria convert the little bit of ammonia to nitrates?

FYI...I tried Bio Spira a couple of weeks ago, but it didn't seem to work for me. Also, I am doing this w/ fish (1 pleco, 3 rosy tetras, and 9 neons.)

 

[richiestang_78]

Yeah just make an educated guess on the number.

 

[RoK]

I'm guessing you mean the pH is 7.0 not 0, right?

 

[Stacie H.]

I'm guessing you mean the pH is 7.0 not 0, right?

Oops!

Yes....7.6 actually. Thanks!

 

[Kilgore]

Hi Stacie H,

I have this problem, too. Especially with the pH and nitrate tests. What makes it easier is when you have two samples with different results and then you can compare them. For example, I thought my guppy tank was pretty high (like 7.6), but then I tested water from a friend's tank and it was so bright blue I think it must have been off the charts. In light of that I reasessed my pH and determined it was probably closer to 7.4.

Same for ammonia - I had trouble deciding when it was closer to 0.5 or 1.0, until I got a water sample from another tank that was very clearly bright green (but not dark) - that was 1.0!

So as the richiestang_78 said, you have to make an educated guess.... now I just try to decide, "Is it more yellow or green?" for ammonia, or more "green or blue" for pH. I like the nitrite test because if it stays blue, you know you're good. The purple is very different.

Hope this helps.

 

[bigmac1878]

i'm glad i'm not the only person with that problem. i have the same test kit and was thinking of getting a new one. i was going to ask the same question until i read this thred

 

[jsoong]

Most of us just guess at the in betweens. I have read that for real fanatics (mostly plant people or show fish people) they make stock solution of known concentrations so they can run tests on that to compare colour with their tank water.

Another way is serial dilution (use that in chem lab all the time). Basically, you need to know the threshold for colour change of your test (eg. for my NH3 test it is 0.5 - change from clear to hint of colour). When you get a positive test, you would dilute your sample with pure water until it turns negative. From the amount of dilution, you can then calculate a fairly accurate level.

However, for cycling, you don't really need all that precision. A ball park value will do just fine.