Test Kit Consistency

[Jattys_Reefs]

Hello fellow reefers,

I'm having some issues with RTN on a handful of LPS and SPS. I think it's because I've been dosing my Alkalinity based off the reading's from my Trident. For the hell of it, I decided to test my Alkalinity with multiple different test kit brands and my results are below.

Trident - 9.5
Salifert - 10.9
Aqua Forest - 9.8
Hanna - 10.5

Average: Approx. ~10.1

It's frustrating that all the test kits give a different result... I'm curious what everyone else does to combat this issue when you get different results.

I'm going to try and calibrate my Trident based off the average I just came up with. I normally calibrate my Trident with the calibration solution they provide when I buy new reagents. I don't think I'm going to use that calibration fluid anymore.

Any advise you guys have would be great. Thanks!

 

[mkpetersen]

I calibrate my apex to Hanna. Why? Just reputation. Have you tried dipping for bacterial infection?

 

[Randy Holmes-Farley Verified Community Expert]

That range looks about as I’d expect for 4 different tests using four different test kits. Using just one may give more consistent results and dosing off that is what I’d recommend.

 

[Pod_01]

You could try to take 3 measurements with each test kits and see if you get consistent results or if you have same variations…

Based on your numbers I would say your Alk is 10.1 with +/- 0.5… Nothing that would lead to RTN…

For my tank I use GHL Kh Director to track trend, 7.5 with +/- 0.5 variation… As long as the value is within that range I ignore the spikes or valleys… and as long as corals look happy no action is required.

Since your corals are not happy I would look at PO4 limitation, N limitation or perhaps trace element limitation. Elevated Alk can promote accelerated growth so you may be limited by other building blocks…

Good luck,

 

[Jattys_Reefs]

You could try to take 3 measurements with each test kits and see if you get consistent results or if you have same variations…

Based on your numbers I would say your Alk is 10.1 with +/- 0.5… Nothing that would lead to RTN…

For my tank I use GHL Kh Director to track trend, 7.5 with +/- 0.5 variation… As long as the value is within that range I ignore the spikes or valleys… and as long as corals look happy no action is required.

Since your corals are not happy I would look at PO4 limitation, N limitation or perhaps trace element limitation. Elevated Alk can promote accelerated growth so you may be limited by other building blocks…

Good luck,

@Pod_01 thanks for your help.

I was accusing the Alk spike as the culprit of my RTN as it did spike relatively quickly by me possibly overdosing. I was averaging around 9.5 (based off Trident) which I'm learning is more like 10.1 after my other test results.

I have no idea what else the issue would be with some of my corals RTNing from the base up. It's so frustrating, especially when I feel like I'm pretty dialed in with the chemistry and stability of my system.

I recently sent in my water samples for an ICP test. Hoping to find out more from that test.

 

[Pod_01]

I have no idea what else the issue would be with some of my corals RTNing from the base up.

Is it RTN or STN? RTN the skin tends to peel off fast at most within 24 hours the coral is all white. STN takes bit of time and can start at base or tip of the corals.

I observed STN at the base of acros when I had low phosphate level (below 0.04ppm) and Alk above 9dKH.

I only experienced RTN with questionable frags that I added to the tank and they peeled within a day. If you have recurring event of RTN that could indicate water chemistry issue (elevated K etc…) and perhaps ICP test could help.

When I unintentionally turned my reef into brackish water some SPS bleached and slowly STN.
Before:

After: Bleached

Good luck,

 

[Jattys_Reefs]

Is it RTN or STN? RTN the skin tends to peel off fast at most within 24 hours the coral is all white. STN takes bit of time and can start at base or tip of the corals.

I observed STN at the base of acros when I had low phosphate level (below 0.04ppm) and Alk above 9dKH.

I only experienced RTN with questionable frags that I added to the tank and they peeled within a day. If you have recurring event of RTN that could indicate water chemistry issue (elevated K etc…) and perhaps ICP test could help.

When I unintentionally turned my reef into brackish water some SPS bleached and slowly STN.
Before:

After: Bleached

Good luck,

Thanks for all your help dude.

From what you said, it sounds like STN. It's not happening SUPER fast. 1-2 weeks and it's definitely noticeable at the base and the tips. But it's not affecting every frag I have. Some of my SPS is doing really well while a bunch are also affected.

My phosphates are pretty low as well. Right around 0.03, but then again, my hanna phosphate checker likes to throw different numbers at me after every test.. so annoying!

I'm hoping I can increase my phosphate levels with the help of Brightwell's NeoPhos.

But to summarize, I think it's my low phosphates and high alkalinity that's causing the STN.

 

[Pod_01]

I'm hoping I can increase my phosphate levels with the help of Brightwell's NeoPhos.

These days I use Tropic Marin Phos Feed to keep phosphate available for corals.

One benefit seems to be less algae vs. other methods that I tried.
You can mix a dose and dose it all at once or break it up during the day.
One negative is that test kits may not be able to measure the PO4 form that is inside Phos Feed so you need to observe your corals, but if dosed daily you know corals are getting phosphate.
I actually don’t measure PO4 since I started using TM Phos Feed…

Couple of my corals:

 

[Hairyteeth]

I find my test kits all
Give about is with 1 dkh the same number, but testing accurately is really hard….i figure im just trying to stay at a number, what ever that may be,
my apex reads 8.15 Hanna (average of 3 tests) says 9.3….i test against the trident once a week and make sure the 8.15 is 9.3
So I feel you and am about to do the same

 

[Arie_Idaho_Reef]

I would recommend comparing the Trident results to your most recent ICP test and using that as your reference point. All your alkalinity tests fall within an acceptable range, so it's unlikely that alkalinity is the cause of your coral tissue necrosis. You mentioned using a Hanna Phosphate Checker and getting a reading of 0.03 ppm. However, keep in mind that the accuracy margin of the Hanna Checker is ±0.04 ppm, which means your actual phosphate level could be close to 0 ppm. If that's the case, your corals might not be receiving enough phosphate, which could lead to tissue issues. I personally aim for around 0.08 ppm PO4 to avoid this problem. Out of curiosity what is NO3 at?

 

[Jattys_Reefs]

I would recommend comparing the Trident results to your most recent ICP test and using that as your reference point. All your alkalinity tests fall within an acceptable range, so it's unlikely that alkalinity is the cause of your coral tissue necrosis. You mentioned using a Hanna Phosphate Checker and getting a reading of 0.03 ppm. However, keep in mind that the accuracy margin of the Hanna Checker is ±0.04 ppm, which means your actual phosphate level could be close to 0 ppm. If that's the case, your corals might not be receiving enough phosphate, which could lead to tissue issues. I personally aim for around 0.08 ppm PO4 to avoid this problem. Out of curiosity what is NO3 at?

Thanks for providing some insight to my concerns.

To answer your question about PO4, I'm at about 3.5-4