Best testing practice: diluting with RO/DI or Fresh Saltwater?

[TimmyD16]

Hi All,

Just wondering what the best practice is when diluting water to test for the standard titration reef tests (NH3/4, NO2, NO3, PO4, etc..) (I'm currently using Red Sea and Salifert if that matters). Is it to use straight RO/DI water, or to mix up some fresh saltwater to better match the tank's water? Essentially asking if the salinity of the test solution has an effect on the result if you are diluting the water?

Thanks in advanced for answering my probably silly question!

 

[Randy Holmes-Farley]

Why are you diluting at all?

 

[Randy Holmes-Farley]

FWIW, none of those tests are titration tests.

A titration involves adding one chemical to another until you get to some endpoint, like a color change. Alkalinity and calcium and magnesium are titrations that we use.

 

[TimmyD16]

Ahh, my mistake, I was under the impression that anytime there was a color shift it was referred to as a titration test, thanks for pointing that out! What is the proper name for these type of tests?

Also I am attempting to increase the testing range for the test, occasionally I max out the provided color chart (currently cycling and trying to get my head around it).

 

[flampton]

Can be referred as colorimetric tests. For Red Sea phosphate and nitrate it’s recommended to dilute with RO/DI. Can't speak for other tests.

 

[flampton]

Oh and welcome to r2r!!!

 

[mike550]

Ahh, my mistake, I was under the impression that anytime there was a color shift it was referred to as a titration test, thanks for pointing that out! What is the proper name for these type of tests?

Also I am attempting to increase the testing range for the test, occasionally I max out the provided color chart (currently cycling and trying to get my head around it).

@TimmyD16 Salifert Calcium is a titration test. If you're running "low resolution" mode, then the directions are to use half the amount of water sample (so 1ml) and 2X the result. Not sure if Salifert Mg allows the same. For Salifert Phosphate, you double the water sample and chemicals to raise sensitivity. Then divide result by two.

What tests are you maxing out?

 

[Randy Holmes-Farley]

Hi All,

Just wondering what the best practice is when diluting water to test for the standard titration reef tests (NH3/4, NO2, NO3, PO4, etc..) (I'm currently using Red Sea and Salifert if that matters). Is it to use straight RO/DI water, or to mix up some fresh saltwater to better match the tank's water? Essentially asking if the salinity of the test solution has an effect on the result if you are diluting the water?

Thanks in advanced for answering my probably silly question!

In a diluted sample of any test for NH3/4, NO2, NO3, and PO4, the only reason to not use salt water is that there may be some of those present, even in new salt water. Especially ammonia.

But if you are maxing a test for those, the small amount in new salt water is not significant, and it won't matter whether you use RO/DI or salt water.

 

[LiveWire]

Welcome to the REEF @TimmyD16

 

[TimmyD16]

Colorimetric tests, good to know! Thanks for the information!

And thanks for the welcome! I've been a long-time lurker, but am finally trying to (slowly) start a reef tank and figured I should be more active in the community!

Thanks everyone for the help!