need some help.. cycle/water testing

[nisi]

Not much help at this point, but I had the exact same issue. Yes, that light blue/gray color on the nitrite test means it's WAY too high for the test kit to measure. As I was cycling I watched nitrites rise from the measurable 5 to a muddy red-brown color to that blue-ish color. And not coincidentally I'm sure, my cycle also stalled. I too was feeding lots of ammonia, which made the nitrites climb too fast. I too did a massive water change a couple days ago and the cycle is moving right along now. Hopefully yours will too!

 

[harmy4993]

so far my nitrites havent budged in 5 day days.

 

[Purrbox]

I generally found that Nitrites stay high for 1-2 weeks before finally dropping. Don't worry a little longer and your cycle will be complete.

 

[AlissasDad]

Sorry to knock the dust off this one, but I had an idea that I wonder if anyone has ever tried in these situations.

Since the drops are simply reacting with the nitrites (or ammonia or any other compound measured in ppm) in the test sample, the sample size itself is irrelevant to the actual reaction.

If the readings are too high with 8 drops of the test solutions, it seems like you can adjust the sensitivity of the results by cutting the number of drops in 1/2. Or...use the same amount of drops but with a 10ml sample instead of 5ml. In either case, the reading will be 1/2 of what they would normally be so all you have to do is double the value of the results to know the actual value of the sample.

Does this make sense?

I've done this when measuring chlorine and TA in swimming pools when the normal readings are off the charts and repeatedly come up with accurate results when compared against wide range tests performed by the pool supply stores.

I've never tried it on a pH reading, but since a pH reading cannot logically show more than 14, if you cut the number of drops in 1/2 (or double the sample size), it seems like you'll never logically get a reading higher than 7. Seems to me like it should work. I hesitate only because of the 0-14 pH scale range that doesn't directly correlate to parts of something.

 

[Alaris]

That doesn't sound too logical. pH is more of a rating than an actual quantity. Just because you only drop half of the chemical or use half or double of the water tested doesn't mean that you can double your result. The number of drops represent what is needed to make a certain chemical reaction with the test water to achieve an accurate result.

 

[AlissasDad]

That doesn't sound too logical. pH is more of a rating than an actual quantity. Just because you only drop half of the chemical or use half or double of the water tested doesn't mean that you can double your result. The number of drops represent what is needed to make a certain chemical reaction with the test water to achieve an accurate result.

Yeah, the more I think about pH the less sure I am that my theory would work on it.

Still seems like it would work on the others though, since it is measuring an actual quantity.

 

[Purrbox]

For tests like Nitrate, Ammonia, etc where you are measuring ppm the sort of thing you are talking about is possible. What you would do is mix your sample water 50/50 with RO water and then test per normal. Then double the results.

 

[AlissasDad]

For tests like Nitrate, Ammonia, etc where you are measuring ppm the sort of thing you are talking about is possible. What you would do is mix your sample water 50/50 with RO water and then test per normal. Then double the results.

Yeah, makes sense!
Thanks!

 

[nisi]

Yeah, the more I think about pH the less sure I am that my theory would work on it.

Still seems like it would work on the others though, since it is measuring an actual quantity.

In theory you could do something like you're suggesting for pH as well, but it would get a lot more complicated. The pH test is measuring a concentration, just like the other tests. It measures the concentration of hydrogen ions. The difference is that pH it isn't a linear scale like the other tests. It's a logarithmic scale. That means each step up on the scale is 10x the concentration of the previous step. While 4ppm of nitrites is double the concentration of 2ppm, a solution with a pH of 4 isn't double the concentration of a pH 2 solution - it's 100x the concentration. I'm sure someone could come up with a formula for how much to dilute and how to calculate the pH of the unknown solution based on diluting with distilled water, but my math & chem is way too rusty to attempt it.


Anyway... all that to say, you're right, practically speaking, it won't work for pH unless you have a bit more chemistry and math knowledge than the average Jo/Joe



Also...

I've never tried it on a pH reading, but since a pH reading cannot logically show more than 14...

Not true, technically. pH can be greater than 14 or less than 1, or even less than 0. It's just that things we normally encounter would all fall into the 1-14 range.