Are the spikes real or measurement error?

[njmaddreefer]

Hello Reefers,

I’m new to the group and looking forward towards meeting and making more reefing buddies .

Anyway, I’m trying to dial in my Neptune Trident System. I get random spikes and dips and wondering if this is likely measurement error or if it’s real.

I take hourly alkalinity measurements mainly because I love looking at the data. I just want to understand why I get a 8.5 dkH dip followed by a 8.9 dkH swell. It does settle afterwards. These swells and dips occur randomly.

I have a 45 gallon lightly stocked SPS tank. I dose 0.5ml/hour of calcium chloride/soda ash during the evening and ramp it up to about 1.3ml/hour during peak photosynthesis hours and gradually decrease the dose back to 0.5ml.

I dose at the return pump section of sump.

I measure from overflow return section in sump.

Note: Measurements are taken at time intervals that correspond with dosing interval.

 

[KrisReef]

I would be interested to place the probe in the display away from the dosing input to see how that looks.

 

[edsbeaker]

My trident produces hills and valleys on the graph too. I think like any test, the results would be accurate within a +/- range. I’m not sure what that range would be for the Trident, though.

I would look at the overall trends and not worry so much about each individual reading. It looks like the graph is staying pretty level which means your alkalinity is pretty stable.

 

[njmaddreefer]

I would be interested to place the probe in the display away from the dosing input to see how that

I would be interested to place the probe in the display away from the dosing input to see how that look

I would be interested to place the probe in the display away from the dosing input to see how that looks.

I wonder the same thing regarding variation vs sample line location. I might experiment

For what it is worth, the sample line is in a spot where the flow has to go up into the display and back down before it’s measured.

It is can be difficult to sample from the display since the trident should be level, or slightly higher than the sample line to avoid a siphon.

 

[KrisReef]

I wonder the same thing regarding variation vs sample line location. I might experiment

For what it is worth, the sample line is in a spot where the flow has to go up into the display and back down before it’s measured.

It is can be difficult to sample from the display since the trident should be level, or slightly higher than the sample line to avoid a siphon.

I’m not familiar with how Trident operates,
I was thinking probe vs sample grab. My bad

 

[njmaddreefer]

My trident produces hills and valleys on the graph too. I think like any test, the results would be accurate within a +/- range. I’m not sure what that range would be for the Trident, though.

I would look at the overall trends and not worry so much about each individual reading. It looks like the graph is staying pretty level which means your alkalinity is pretty stable.

I track what you are saying regarding the trend .

Neptune advertises accuracy of +/- 0.5 dkH. I wonder if this is additional measurement error: dirty sample line/ bubbles ?

 

[KrisReef]

Can you offset the measurements so that the sample is taken after the kh inputs have circulated and the sump better reflects the DT?

 

[njmaddreefer]

Can you offset the measurements so that the sample is taken after the kh inputs have circulated and the sump better reflects the DT?

For sure I’ll try this tomorrow!

 

[edsbeaker]

Can you offset the measurements so that the sample is taken after the kh inputs have circulated and the sump better reflects the DT?

My alk is dosed 1/2 hour before tests are run, but I still get those spikes.

 

[KrisReef]

My alk is dosed 1/2 hour before tests are run, but I still get those spikes.

The spikes look huge but this could be just an artifact of small measurement changes graphed on a narrow range?

Sometimes the data and the presentation are the whole story.

 

[njmaddreefer]

My alk is dosed 1/2 hour before tests are run, but I still get those spikes.

Thanks good to know I’m not the only one who gets these peaks and valleys. Definitely taking your advice and will focus more on the trend.

 

[edsbeaker]

The spikes look huge but this could be just an artifact of small measurement changes graphed on a narrow range?

Sometimes the data and the presentation are the whole story.

I think this is true. The majority of data on the graph is only registering a difference of .1 dkh, with results jumping between around 8.7-8.8 with a couple major spikes, but I think that’s probably the Trident being a Trident. But OP is testing every single hour so, yes, the spikes are very close to one another. My Trident shows about the same jump range. I will also get those occasional ridiculous high spikes, too, that I just contribute to testing error.

Here’s my graph, testing every six hours instead of every hour. To me, it doesn’t look nearly as extreme.

 

[Dan_P]

Hello Reefers,

I’m new to the group and looking forward towards meeting and making more reefing buddies .

Anyway, I’m trying to dial in my Neptune Trident System. I get random spikes and dips and wondering if this is likely measurement error or if it’s real.

I take hourly alkalinity measurements mainly because I love looking at the data. I just want to understand why I get a 8.5 dkH dip followed by a 8.9 dkH swell. It does settle afterwards. These swells and dips occur randomly.

I have a 45 gallon lightly stocked SPS tank. I dose 0.5ml/hour of calcium chloride/soda ash during the evening and ramp it up to about 1.3ml/hour during peak photosynthesis hours and gradually decrease the dose back to 0.5ml.

I dose at the return pump section of sump.

I measure from overflow return section in sump.

Note: Measurements are taken at time intervals that correspond with dosing interval.

The variation in alkalinity you see is very small and there appears to be a regular pattern of peaks and valleys in the variation. Such variation could simply be the variation in measuring alkalinity. Another source of variation is the amount of alkalinity added by the dosing pump. There might also be electronic cross talk between various pieces of equipment. AC voltage fields (60 cycle/sec variation) might be influencing the reading .