First ICP test... Mostly ok?

[rishma]

My magnesium salifert test would read low too so I bought a different brand test kit and it was more believable. The salifert was like 300 low, glad I trusted my gut instincts ha ha.

Better yet, trust the math and just dose 1-2ppm for every 2.8 dKH alkalinity you you dose. That’s my preferred approach.

 

[AustinB]

Definitely agree about salinity! The magnesium was interesting because my Salifert test always reads below 1300 so I've been dosing a little. But after some research I agree 1481 isn't anything to stress about. No idea why it said my alk was high! I knew better! Thanks so much the the response

Stop ALL dosing of magnesium. The salinity boost is going to raise it further.

I do not recommend or use home magnesium testing due to the error likelihood.

Randy so happy to hear from you directly! Your advice on R2R has helped this new reefer SO MUCH! I will definitely stop dosing magnesium! I'll probably finally get an ATO.

I also see your comment about the trace elements. I'd rather NOT dose AFR or anything else unless you think it's really needed like with the iron or manganese?

Appreciate any advice or suggestions!

I got a used Tunze 3155 with a used tank I bought and it’s been awesome for 7 years, plus however long the previous owner used it for. So even a second hand higher end ATO is better than an off brand cheaper one in my opinion.

 

[SaltySuz]

@Randy Holmes-Farley I tried to reply above but not sure it tagged you-

Randy so happy to hear from you directly! Your advice on R2R has helped this new reefer SO MUCH! I will definitely stop dosing magnesium! I'll probably finally get an ATO.

I also see your comment about the trace elements. I'd rather NOT dose AFR or anything else unless you think it's really needed like with the iron or manganese?

Appreciate any advice or suggestions!

 

[slingfox]

I would not pay too much attention to the reported salinity.

ICP does not directly measure salinity and the number on that report is a number calculated based on the ionic composition of the sample.

You should calibrate your refractometer with a known good standard solution which you can make yourself using table salt and a scale.

An article that explains how to make the DIY solution is

Reef Aquarium Salinity: DIY Calibration Standards

Reef Aquarium Salinity: DIY Calibration Standards By Randy Holmes-Farley One of the most important issues facing marine aquarists is providing a suitable environment for their aquaria's inhabitants. Among the important properties for a marine...

www.reef2reef.com

I also use a refractometer to track my salinity and it pretty much always comes up inline on the ICP. This is the first part of my ICP earlier this month from ATI:

 

[Randy Holmes-Farley]

@Randy Holmes-Farley I tried to reply above but not sure it tagged you-

Randy so happy to hear from you directly! Your advice on R2R has helped this new reefer SO MUCH! I will definitely stop dosing magnesium! I'll probably finally get an ATO.

I also see your comment about the trace elements. I'd rather NOT dose AFR or anything else unless you think it's really needed like with the iron or manganese?

Appreciate any advice or suggestions!

I can’t tell if you might benefit from a trace supplement or not from that icp. If things seem ok it is likely fine to not do so.

 

[slingfox]

Thanks for the input! I recalibrate my refractometer with an appropriate solution monthly

If you are using one of those off-the-shelf refractometer solutions there is no assurance they are actually right. The only calibration solution would trust is solution you make yourself pursuant to the directions from @Randy Holmes-Farley

Also, I started the hobby using a $35 refractometer from one of the major online reefing retailers. It was super inaccurate (it read too high so my salinity was constantly too low). I tried calibrating with three different solutions and could not get it to read consistently. Once I upgraded to the VeeGee I have had zero issues. I have calibrated it three times (once every six months) and every time there has been zero need for adjustment and my ICPs line up perfectly as shown in my screenshot above.

 

[rishma]

If you are using one of those off-the-shelf refractometer solutions there is no assurance they are actually right. The only calibration solution would trust is solution you make yourself pursuant to the directions from @Randy Holmes-Farley

Also, I started the hobby using a $35 refractometer from one of the major online reefing retailers. It was super inaccurate (it read too high so my salinity was constantly too low). I tried calibrating with three different solutions and could not get it to read consistently. Once I upgraded to the VeeGee I have had zero issues. I have calibrated it three times (once every six months) and every time there has been zero need for adjustment and my ICPs line up perfectly as shown in my screenshot above.

In recent years I have observed that a leading cause of elements being outside target range is the poor accuracy of hobby salinity measurement. I feel like people put far more effort and money into less important measurements.

 

[slingfox]

In recent years I have observed that a leading cause of elements being outside target range is the poor accuracy of hobby salinity measurement. I feel like people put far more effort and money into less important measurements.

People are willing to shell out hundreds of dollars on lights and coral but are okay relying on cheap refractometers where they can pay a little bit more for a TM hydrometer or a high quality refractometer (ie, the VeeGee) and make their life so much easier.

 

[rishma]

People are willing to shell out hundreds of dollars on lights and coral but are okay relying on cheap refractometers where they can pay a little bit more for a TM hydrometer or a high quality refractometer (ie, the VeeGee) and make their life so much easier.

exactly. TM hydrometer is my standard recommendation. Low cost, check it once. Never needs calibration. It should be standard for new reefers. There are other good options, but a nearly infinite number of bad options.

 

[Jxw6963]

I use a refractometer to measure salinity and check if it needs recalibration monthly . It's possible it dipped that low. I often let it sit at 1.025 and (I know many will cringe here) I don't have an ATO. I top off manually when feeding twice a day. I've heard too many horror stories about malfunction and

I regularly run into issues with temperature significantly affecting my refractometer readings. Both during calibration, or measuring. I find myself calibrating or verifying just about everytime i use it just in case.

Ideally try to use cal and sample fluid at the same temp everytime, just in case

One indicator that you have measurement issues is if you frequently seem to have to correct salinity. Normally its pretty stable with consistent top offs

 

[SaltySuz]

I use a refractometer to measure salinity and check if it needs recalibration monthly . It's possible it dipped that low. I often let it sit at 1.025 and (I know many will cringe here) I don't have an ATO. I top off manually when feeding twice a day. I've heard too many horror stories about malfunction and

I regularly run into issues with temperature significantly affecting my refractometer readings. Both during calibration, or measuring. I find myself calibrating or verifying just about everytime i use it just in case.

Ideally try to use cal and sample fluid at the same temp everytime, just in case

One indicator that you have measurement issues is if you frequently seem to have to correct salinity. Normally its pretty stable with consistent top offs

I don't have to correct it often and even though I check my refractometer with the calibration fluid monthly it's rare for me to actually need it adjust. Even when I do the amount is minuscule. This is the one I use.

 

[slingfox]

I don't have to correct it often and even though I check my refractometer with the calibration fluid monthly it's rare for me to actually need it adjust. Even when I do the amount is minuscule. This is the one I use.

Why not adjust your salinity when you send you ICP out? I definitely would not trust that refractometer but if it works for you great. This is definitely one of the worst areas to skimp on.

 

[gbroadbridge]

I don't have to correct it often and even though I check my refractometer with the calibration fluid monthly it's rare for me to actually need it adjust. Even when I do the amount is minuscule. This is the one I use.

That refractometer is fine PROVIDED that it is calibrated correctly with a suitable standard - as mentioned earlier, do not trust any purchased calibration solution - make your own.

 

[Jxw6963]

I don't have to correct it often and even though I check my refractometer with the calibration fluid monthly it's rare for me to actually need it adjust. Even when I do the amount is minuscule. This is the one I use.

Same as mine. Here's another thought, just in case you didnt notice. The refractometer readings will shift if you tilt the refractometer up. Also, if you raise or lower your eye in the scope you can see it shift.
The other thing is it may be better to target the salinity side of the scale, not the specific gravity.
Don't get me wrong, maybe you're ok now, and you just had a slight dip, but ICP is definitely more reliable than the refractometer, just poinying out all of the pitfalls of the refractometer.
I also picked up a glass hydrometer as a double checker, since I grew to not trust the refractometer

 

[Randy Holmes-Farley]

I regularly run into issues with temperature significantly affecting my refractometer readings. Both during calibration, or measuring. I find myself calibrating or verifying just about everytime i use it just in case.

Ideally try to use cal and sample fluid at the same temp everytime, just in case

One indicator that you have measurement issues is if you frequently seem to have to correct salinity. Normally its pretty stable with consistent top offs

What sort of refractometer? Most automatically compensate for temp changes.

What is that table? I think it is highly unlikely to apply to anything except a glass hydrometer reading.

 

[Jxw6963]

What sort of refractometer? Most automatically compensate for temp changes.

What is that table? I think it is highly unlikely to apply to anything except a glass hydrometer reading.

Yea, mine does have ATC, but i guess my point was if it is not precisely correcting for temperature, or liquid temp is different. I have noticed it swings if temperature changes

 

[Jxw6963]

What sort of refractometer? Most automatically compensate for temp changes.

What is that table? I think it is highly unlikely to apply to anything except a glass hydrometer reading.

Does it correct for ambient or liquid temp? Today, Mine shows 20c no matter the liquid temp. if i put 78F water on it, or if i put 65F water, it still shows me 20c which is the same as ambient

The table i posted above shows the impact if you have a refractometer calibrated in 20c ambient you will get different readings if the liquid sample is at different temps

 

[Randy Holmes-Farley]

Does it correct for ambient or liquid temp? Today, Mine shows 20c no matter the liquid temp. if i put 78F water on it, or if i put 65F water, it still shows me 20c which is the same as ambient

The table i posted above shows the impact if you have a refractometer calibrated in 20c ambient you will get different readings if the liquid sample is at different temps

Is that a table you made, or off the web? If the latter, it almost certainly is a hydrometer reading table, which would not apply to refractometers. It is not a table of actual sg changes, but of hydrometer readings. Real sg changes are very small.

A refractometer labeled at ATC (which most are) will autocorrect within a reasonable range from room temp. The fluid added does rapidly come to the temp of the refractometer.

 

[Jxw6963]

Is that a table you made, or off the web? If the latter, it almost certainly is a hydrometer reading table, which would not apply to refractometers. It is not a table of actual sg changes, but of hydrometer readings. Real sg changes are very small.

A refractometer labeled at ATC (which most are) will autocorrect within a reasonable range from room temp. The fluid added does rapidly come to the temp of the refractometer.

I see, to confirm what you are saying,
The method of retracting light to measure does not get as impacted as much by temperature differences as a glass floating type hydrometer would?

If so, for example, these two scenarios would not result in the same error:
1. Hydrometer calibrated at 20c but measuring 25c water
2. Refractometer adjusting for 20c ambient but it's actually 25c ambient

I was assuming they would have the same error, but I see now maybe that's not right

 

[js-3Design]

If i where you i would also put more effort to your trace elements. Not detectable isnt a good thing.
You need those...
Also, stop doing icp tests and do a real lab test, modern reef has those. They are more expensive but way more acurate.