Salinity Question

[Shevlin77]

Hi -
I have a 10 gallon mixed reef which is being slowly being m transitioned to SPS heavy. The tank is happy and everything is growing. I albeit at at different rates.

Recently started doing ICP tests to see if I could optimize SPS growth via dosing trace elements. The last three ICP tests, over the past few months all come in at around 31 to 32 PSU. It’s been a bit of a surprise because the hydrometer is showing one 1.025 at a temperature of 77°.

Anyway, should I raise that salinity level to the recommend 35 psu?

Half of me doesn’t want to mess with it unless doing so could provide some positive benefits, because again everything seems to be thriving right now. Wondering if my tank has gotten accustomed to a slightly lower salinity level.

Thanks!

 

[KStatefan]

I would make a test solution to check your hydrometer.

 

[Shevlin77]

I would make a test solution to check your hydrometer.

I’ll do that but I should trust three straight ICP tests at 31/32 PSU, right?

Thanks for the reply.

 

[DanyL]

First of all, corals can adapt to a wide verity of salinity levels.
For example, the salinity in the Red Sea is around 40ppt.

That being said corals also prefer stability, and when you'll introduce new inhabitants that were regular to a different salinity level they'll have to adjust and go though more stress than usual.

Now, both ICP and your hydrometer can lie, it happens.
What I suggest you to do is to either take a sample of your water to the LFS, make sure their measurement equipment is correctly calibrated and test your water there, or to purchase a reference solution and test your own hydrometer.

If the hydrometer was lying, then you know it needs to be replaced, otherwise you know you can trust it over the results you got from the ICP test, and you may also let them know about it.

 

[Not an IT guy]

Get a different measuring tool. Refrac one works the best. I’d stay away from electronic ones.

 

[Randy Holmes-Farley]

Sg = 1.025 = 33 ppt, so your values are not differing by much.

 

[Randy Holmes-Farley]

Get a different measuring tool. Refrac one works the best. I’d stay away from electronic ones.

lol

You gave the same answer as the ChatGPT yesterday in the Chem forum, though I do not agree with it. Conductivity meters are great, as long as you get a quality device.

ChatGPT and Reef Chemistry: We Try it Out!

Why didn't I think of this sooner. No need to have a real person helping out. lol Here are a few examples that I asked it today, in order of increasing difficulty (IMO): 1. Describe the importance of alkalinity and calcium in a coral reef aquarium. ChatGPT reply: Alkalinity and calcium are...

www.reef2reef.com

 

[srobertb]

Buy a digital salinity tester. Top 10 purchase in 10+ years easily.

I wouldn’t worry too much. I also wouldn’t chase numbers in a 10g tank. As someone with a 10g tank…I have no idea what the numbers are.

Weekly water changes will do all you need.

 

[Shevlin77]

Buy a digital salinity tester. Top 10 purchase in 10+ years easily.

I wouldn’t worry too much. I also wouldn’t chase numbers in a 10g tank. As someone with a 10g tank…I have no idea what the numbers are.

Weekly water changes will do all you need.

thanks and will do …. ps it’s actually 110 gallon tank but it’s 10 years old.

 

[Randy Holmes-Farley]

FWIW, it is always cheaper to dose to supplement calcium and alkalinity than to do water changes, unless you are already doing those same water changes for other reasons.

 

[All_talk]

Does the ICP teat reference a temperature for the PSU reading? When you say hydrometer do you mean the swing arm style or floating glass bulb type?

In any case I would do nothing right away, dig into the testing variance first. And if you decide to make an adjustment, I would do it very slowing so your happy tank stays happy.

 

[srobertb]

thanks and will do …. ps it’s actually 110 gallon tank but it’s 10 years old.

Lol. Sorry. I read it as “10g”.

Absolutely chase numbers

I aim for 35ppt which is easy with a digital refractometer and ATO to dial in. Honestly with all the dosing and the AWC drifting I range 1.025-1.028 and it’s never been an issue vs say Alk drifting 2pts.

The smart people will tell you to adjust it slowly over a week or two but honestly I’m guilty of stealing my wife’s big measuring cup and just dumping 1/2gallon of water out of the tank and letting the ATO do the rest or mixing a salty slurry and adding it into the overflow.
(On my 125)

 

[nuxx]

If you are truly at 1.025 I'd leave it.

I'd keep mine between 1.025-1.026.

Everything looks happy, don't go changing stuff

 

[Randy Holmes-Farley]

Does the ICP teat reference a temperature for the PSU reading? When you say hydrometer do you mean the swing arm style or floating glass bulb type?

In any case I would do nothing right away, dig into the testing variance first. And if you decide to make an adjustment, I would do it very slowing so your happy tank stays happy.

ICP determines concentration in a way that should be independent of temperature. Ppt and PSU are not temp dependent.

 

[Shevlin77]

Does the ICP teat reference a temperature for the PSU reading? When you say hydrometer do you mean the swing arm style or floating glass bulb type?

In any case I would do nothing right away, dig into the testing variance first. And if you decide to make an adjustment, I would do it very slowing so your happy tank stays happy.

It does not reference a temperature that I can see. It was an ATI test. I see what you’re getting at though because maybe they analyzed the sample at a lower temperature than my tank water?

miss spoke earlier meant to say refractometer! it’s an ATC refractometer.

Thanks!

 

[Not an IT guy]

lol

You gave the same answer as the ChatGPT yesterday in the Chem forum, though I do not agree with it. Conductivity meters are great, as long as you get a quality device.

ChatGPT and Reef Chemistry: We Try it Out!

Why didn't I think of this sooner. No need to have a real person helping out. lol Here are a few examples that I asked it today, in order of increasing difficulty (IMO): 1. Describe the importance of alkalinity and calcium in a coral reef aquarium. ChatGPT reply: Alkalinity and calcium are...

www.reef2reef.com

I am not a robot. Beep boo beep boo

 

[DanyL]

I am not a robot. Beep boo beep boo

Well.. you also say you're not an IT guy either
sus.

 

[Randy Holmes-Farley]

It does not reference a temperature that I can see. It was an ATI test. I see what you’re getting at though because maybe they analyzed the sample at a lower temperature than my tank water?

miss spoke earlier meant to say refractometer! it’s an ATC refractometer.

Thanks!

No, not a concern. 35 ppt or PSU is an attribute of the water, not the temperature it is at.

 

[Shevlin77]

No, not a concern. 35 ppt or PSU is an attribute of the water, not the temperature it is at.

thanks Randy.

looking back really wish I went for a chemistry degree instead of a business degree. lol