Do I need to change my protocol testing ammonia with Hach?

[ARCkeeper]

I run about 15 to 20 water samples for ammonia on a Hach once a week. Only three samples are from marine systems and they always come out as a negative number with the comment that the sample is below testing range. All the freshwater samples get realistic results. The blank used to zero the machine is prepared with distilled water per the instructions. Do I need to run a blank prepared with saltwater to get an accurate result?

 

[Jekyl]

I haven't tested ammonia in my tank in about 4 years. Once cycle is complete there's no reason.

 

[vetteguy53081]

I run about 15 to 20 water samples for ammonia on a Hach once a week. Only three samples are from marine systems and they always come out as a negative number with the comment that the sample is below testing range. All the freshwater samples get realistic results. The blank used to zero the machine is prepared with distilled water per the instructions. Do I need to run a blank prepared with saltwater to get an accurate result?

Assure you are not testing right after a water change or feeding.
While constant zero readings are not impossible, it’s unusual

 

[brandon429]

he or she who scores both a hach and a seneye will be set to give the most updated cycling science in all of reefdom, above anyone.

the dynamics that could be discerned with those two meters benchmarking each other is priceless, to cycle nerds who dream about such a pairing.

you know what I'd love to see on just the hach: one simple true unassisted cycling test.

take a vase or some medium container to keep in your home open topped but topped off. heating doesn't really matter if its inside your home where temps are human tolerant. circulation would help, a common bubbler or if you can't stand the noise then use a dropped in power head.

simply add mixed saltwater up to common specs, some dry rocks we'd use for reefing, fill it up, and let the whole mix stew for 2 months without adding any feed or any bottle bac.

at the end of two months do a full water change for new water

use a volume calculator to input the degree of ammonia it would take to be ~.5 ppm maximum

use the hach measure to verify the nh3 conversion off that input is accurate to the known charts.
if you have a quality pH meter/probe that would help but if you don't, the water change just put you within common pH specs of any reef here.

then retest that setup in 24 hours to see if natural means cycled the mini test tank, which I bet it does on digital meters. all of cycling science will be in an uproar if it passes, and if it doesn't they'll drum me out of town but I'll still post from the road.

 

[brandon429]

any testing you may do in a running reef tank with that hach would also be priceless: hardly any of us agree on what the running nh3 baseline is even for a common running and stocked up reef. even a basic range would be so helpful so we can compare what you find to about 300 online logs from seneye in running reef tanks. that hach can be used for such a profound forwarding of cycling science for reefing.

 

[Randy Holmes-Farley]

I run about 15 to 20 water samples for ammonia on a Hach once a week. Only three samples are from marine systems and they always come out as a negative number with the comment that the sample is below testing range. All the freshwater samples get realistic results. The blank used to zero the machine is prepared with distilled water per the instructions. Do I need to run a blank prepared with saltwater to get an accurate result?

Which Hach ammonia method and device?

 

[ARCkeeper]

Which Hach ammonia method and device?

We use salicylate test on a (I believe - I'm not at work right now) Hach DR3900

 

[Randy Holmes-Farley]

Hach says that calcium interferes with the method 8155 ( 0.01 to 0.5 ppm NH3-N salicylate method) at levels of calcium of 1,000 ppm CaCO3, which is the same as 400 ppm calcium

I cannot tell if it is a positive or negative interference, but it is in the range of causing problems when using a RO/DI blank for a seawater sample.

https://www.hach.com/asset-get.download-en.jsa?id=7639983745

Their other method, #10023, has higher tolerance for calcium.

https://www.hach.com/asset-get.download-en.jsa?id=7639983748

 

[Malcontent]

Almost all of Hach's ammonia methods are salicylate.

 

[Malcontent]

I've used method 8155 to test ammonia in a 10%(?) NaCl solution used to regenerate zeolite but not seawater. The blank was distilled water and I didn't have any obvious issues.

 

[ARCkeeper]

Hach says that calcium interferes with the method 8155 ( 0.01 to 0.5 ppm NH3-N salicylate method) at levels of calcium of 1,000 ppm CaCO3, which is the same as 400 ppm calcium

I cannot tell if it is a positive or negative interference, but it is in the range of causing problems when using a RO/DI blank for a seawater sample.

https://www.hach.com/asset-get.download-en.jsa?id=7639983745

Their other method, #10023, has higher tolerance for calcium.

https://www.hach.com/asset-get.download-en.jsa?id=7639983748

The three marine samples I run are from reef tanks that we maintain at about 400 ppm calcium. I'll have to look into method 10023 when we reorder reagents. Thank you.

 

[ARCkeeper]

Hach says that calcium interferes with the method 8155 ( 0.01 to 0.5 ppm NH3-N salicylate method) at levels of calcium of 1,000 ppm CaCO3, which is the same as 400 ppm calcium

I cannot tell if it is a positive or negative interference, but it is in the range of causing problems when using a RO/DI blank for a seawater sample.

https://www.hach.com/asset-get.download-en.jsa?id=7639983745

Their other method, #10023, has higher tolerance for calcium.

https://www.hach.com/asset-get.download-en.jsa?id=7639983748

I double checked. We are using method 8155 on a DR3900. I tried to manually enter method 10023 but the program doesn’t appear to be in the memory. We may have to wait until the next calibration to have Hach install it