1.024 or 1.026, what's your preference and why?

SaltwaterGuruNeeded · Jul 21, 2021

Which is a better overall salinity for fish, 1.024 or 1.026 and why?

Gedxin · Jul 21, 2021

What if I said 1.025?

Jekyl · Jul 21, 2021

35ppt. My coral prefer it.

SaltwaterGuruNeeded · Jul 21, 2021

Gedxin said:
What if I said 1.025?

Yeah, that could be an option. But debating whether 1.024 or 1.026 is better.

Randy Holmes-Farley · Jul 21, 2021

I doubt it matters, but 35 ppt (sg = 1.0264 ) is the worldwide ocean average.

If you used natural seawater and were at sg = 1.024, all of the major ions would be low (e.g., magneisum at 1164 ppm).

SaltwaterGuruNeeded · Jul 21, 2021

Randy Holmes-Farley said:
I doubt it matters, but 35 ppt (sg = 1.0264 ) is the worldwide ocean average.

If you used natural seawater and were at sg = 1.024, all of the major ions would be low (e.g., magneisum at 1164 ppm).

Lfs said that as salinity increase they have to breathe more often.

Gtinnel · Jul 21, 2021

I try to keep mine at 1.026 but occasionally it will dip down to 1.025. My assumption has always been that keep it stable is more important than the specific number.

Screwgunner · Jul 21, 2021

I run my water 1.024 with my swing arm . When I check it with my refractometer it comes out 1.026.

Randy Holmes-Farley · Jul 21, 2021

SaltwaterGuruNeeded said:
Lfs said that as salinity increase they have to breathe more often.

Yes, the fish in the ocean are slowly suffocating. lol

The tiny nugget of truth behind that claim is that O2 saturation is a teeny tiny bit higher at sg = 1.024 than at sg = 1.026. 6.89 mg/L O2 vs 6.79 mg/L O2.

That difference is very small, and there's no reason to assume the O2 is ever governed by the saturation level. It can be both higher (during the day ) and lower (at night).

LFS usually keep salinity lower because it is cheaper. Anything else (except hypo) is just an excuse, IMO.

MaxTremors · Jul 21, 2021

SaltwaterGuruNeeded said:
Which is a better overall salinity for fish, 1.024 or 1.026 and why?

1.026 or 35ppm, closer to natural seawater.

Grey Guy · Jul 21, 2021

SaltwaterGuruNeeded said:
Which is a better overall salinity for fish, 1.024 or 1.026 and why?

It is my understanding that the higher the salinity, the less oxygen is in the water. Great for corals, bad for fish. In the old days if you cared for your fish, it was common to keep salinity at 1.022.

Screwgunner · Jul 21, 2021

For fish only 1.020 1.024 reef tank 1.025 1.026

husemn · Jul 21, 2021

1.027.... My corals are happier there.

Randy Holmes-Farley · Jul 21, 2021

Grey Guy said:
It is my understanding that the higher the salinity, the less oxygen is in the water. Great for corals, bad for fish. In the old days if you cared for your fish, it was common to keep salinity at 1.022.

Not so true, as I show above.

arking_mark · Jul 21, 2021

SaltwaterGuruNeeded said:
Which is a better overall salinity for fish, 1.024 or 1.026 and why?

Better question is how are you measuring it.

My hobby measuring tools don't do a great job (Hanna, GHL, Refractometer). I found this out and ended up crosschecking with a high-precision TM Hydrometer. Now I have confidence in my salinity and its at 1.0264 (automatically maintained through GHL).

Randy Holmes-Farley · Jul 21, 2021

Ocean acidification alters temperature and salinity preferences in larval fish

Ocean acidification alters temperature and salinity preferences in larval fish - Oecologia

Ocean acidification alters the way in which animals perceive and respond to their world by affecting a variety of senses such as audition, olfaction, vision and pH sensing. Marine species rely on other senses as well, but we know little of how these might be affected by ocean acidification. We...

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