Who to trust?

[reefpoor]

Can you guys elaborate on why you would not dip vials into tank water to rinse, before running test

[BeakerBob]

Let's start from the beginning:

Are all test kits the same? NO. The quality control on test kits vary by manufacturer. Lamott & Hach test kits are most reliable. All saltwater test kits are semi-quantitative.....WHY?...they lack the quality control needed to ensure accuracy & precision. If you want to make sure your test kits are accurate, precise and reproducible, then you MUST run a positive and negative control. The positive MUST be of a certain value of which you compare the tank water test result with.

Which test kits are the most reliable? In my experience, Hach and Lamotte are the most reliable and consistent. The reason for this is because they are sold primarily for testing drinking and waste water samples, not aquarium tank water.

How often do you need to check the calibration of the test kits and probes? I would check as often as I felt that they are stable. pH probes tend to drift, so they need to be checked at least once a week even if they are properly stored. Refractometers are a little more stable, but the calibration fluid is cheap, so why not check each time? Nitrate/Nitrite kits should be checked at the 1st time to make sure it is accurate and precise, and at least monthly if the reagents are opened. The new Hanna Phosphate meter checks itself by blanking with neat tank water 1st, then with the reagents.

[BeakerBob]

Can you guys elaborate on why you would not dip vials into tank water to rinse, before running test

You do not want to take the chance of contaminating your tank water with chemical reagents. You should take an aliquot of the tank water out of the tank and put it into a separate container. Use this sample to test your tank parameters. Do NOT put any left over sample water back into your tank.

This is basic chemistry testing laboratory procedures. It prevents contaminating the main source (tank) in the event you forget what you are doing or make a mistake.

[ReeferRob]

BEAKERBOB- What would you suggest as the most reliable calibration solutions for refractometers and say Digital Aquatics pH and salinity probes? I have some DIYREEF.COM refractor solution, but unsure of quality and shelf life?

[reefpoor]

I have always rinsed vials after testing in RO water, again in RO water before using the next time. Then I would dip/rinse in tank water and run test. I have no idea where I got that from, but we won't be doing that any more.

You do not want to take the chance of contaminating your tank water with chemical reagents. You should take an aliquot of the tank water out of the tank and put it into a separate container. Use this sample to test your tank parameters. Do NOT put any left over sample water back into your tank.

This is basic chemistry testing laboratory procedures. It prevents contaminating the main source (tank) in the event you forget what you are doing or make a mistake.

[schminksbro]

I trust Lamotte alk kits but I don't test for anything else. I just look at my tank.

[Bluering]

API ..... Tested against salifert and lamotte, came up with similar results to close to pay that higher dollar amount.

[jimsflies]

Bob is there a source that a reefer could get check samples (known concentrations) to run their own verification on test kits? I'm sure there could be variability by batch or lot for a given manufacturer. Would it be worth it for the reefer who is concerned about achieving the best results possible to run an occasional check sample...or at least do one each time they open a new pack of reagents?

[stunreefer]

Based on my findings, relying on API can be quite dangerous. API was telling me I was in the money, then I cross referenced it to the Salifert and I was at almost 50ppm before a past due water change.

Yeah, A.P.I. is quick and easy, but past that they're definitely the lower end of the totem pole IIRC, I've only tested NO3 once since November (when the AGE went back up) so I'm not too worried about it. Corals and fish are very happy I would be skeptical of your 50 ppm reading from Salifert though - many corals would not be too happy with that level, although I did see you mention some favia issues as of late. I would also expect your Acros to be pretty ticked off at 50 ppm.

I use a refractormeter and calibrate it with RO every 4-6 months.

You should consider recalibrating your refractometer more frequently, and definitely use Calibration Solution, not RO water. RO water calibrate to the low end of the scale, and we want mid range (depending on your scale).

[ReeferRob]

I would be skeptical of your 50 ppm reading from Salifert though - many corals would not be too happy with that level, although I did see you mention some favia issues as of late. I would also expect your Acros to be pretty ticked off at 50 ppm.

See that's the thing, everything in the DT is just fine. Everything is happy, well except me.......
The favia issue is going on in the "grow out." Different tank.