zooplankton/phytoplankton?

MizTanks · 09-02-2011, 01:56 PM

First question is about zooplankton/phytoplankton for filter feeders and maybe even some corals. Do you have any recommendations?

Second is can I make my own calibration fluid for my refactor meter?

Thanks in advance

BeakerBob · 09:32 PM

I have not ventured into the zooplankton/phytoplankton production, but there are a number of folks that have....maybe we can get them to post.

Making refractometer calibration fluid is easy - if you have the right tools. An analytical grade balance to precisely weigh out the NaCl and a volumetric flask is needed.

However, if you want to give it a try, you can get pretty close by dissolving 3.65 grams of NaCl into 96.35 mL of RODI. If you don't have the tools for this type of measurement, you can do the following*:

1. Measure 1/4 cup of Morton's Iodized Salt (about 73.1 g)

2. Add 1 teaspoon of salt (making about 79.3 g total salt)

3. Measure the full volume of a plastic 2-L Coke or Diet Coke bottle filled with purified freshwater (about 2104.4 g)

4. Dissolve the total salt (79.3 g) in the total water volume (2104 g) to make an approximately 3.65 weight percent solution of NaCl. The volume of this solution will be slightly larger than the Coke bottle, so dissolve it in another container.

*from Reef Aquarium Salinity: Homemade Calibration Standards

Since most people don't have the necessary instruments and tools to precisely weigh chemicals to make calibration solutions, they buy them to ensure quality and precision. I will have some available at the Ann Arbor swap if you would like to get it there.

MizTanks · 09-02-2011, 07:53 PM

Quote:

Originally Posted by BeakerBob

I have not ventured into the zooplankton/phytoplankton production, but there are a number of folks that have....maybe we can get them to post.

Making refractometer calibration fluid is easy - if you have the right tools. An analytical grade balance to precisely weigh out the NaCl and a volumetric flask is needed.

However, if you want to give it a try, you can get pretty close by dissolving 3.65 grams of NaCl into 96.35 mL of RODI. If you don't have the tools for this type of measurement, you can do the following*:

1. Measure

Hey you didn't finish!!!

MyNemesis · 09-02-2011, 07:59 PM

You can buy calibration fluid. Debbie Berlin used to sell it. Why don't you use distilled water and calibrate it at zero. That should work just fine.

MizTanks · 09-02-2011, 08:27 PM

Quote:

Originally Posted by MyNemesis

You can buy calibration fluid. Debbie Berlin used to sell it. Why don't you use distilled water and calibrate it at zero. That should work just fine.

I was wondering about that. Just wasn't sure I could use it or not. Thanks MyNemesis

BeakerBob · 09-02-2011, 09:38 PM

I edited my reply to complete the remaining content. As a chemist, I have the available instrumentation and tools to accurately make this calibration fluid and was the source for Debbie's supply.

Do not calibrate with RO/DI water to zero unless you have a very good laboratory grade refractometer (very expensive!). The refractomteres currently sold for the aquarium trade are not linear from zero to 1.030. You MUST calibrate within the seawater measurement range to get the best precision and accuracy. This means calibrating at 35ppt or 1.026.

MizTanks · 09-03-2011, 09:38 AM

No way I can make the swap-but if your willing to ship I'll def buy some from you

MyNemesis · 09-03-2011, 09:50 AM

Sorry, I didn't mean to give you a bum steer. I use the calibration fluid, but thought you could use the distilled water as well. I guess that is why we have experts! Learn something new every day in this hobby.

BeakerBob · 09-03-2011, 08:15 PM

John, you did not steer anyone in the wrong direction.

Calibrating with distilled water to zero was, and is, still a common practice in calibrating instrument grade analytical refractometers. This type of calibration instruction is often included with the inexpensive reef refractometers that are being sold today. Unfortunately, these reefing refractometers are not linear from zero to 1.030, so you must calibrate at/near the point of measurement use. The 35 ppt/1.026 SG calibrating fluid is the best to use for the reefing application using the inexpensive reefing refractometers. They should be accurate for our use once it is properly calibrated and maintained.