Evaporation and ions

Cory · Dec 25, 2014

Just discovered my salinity is at 1.024-23 via refractometer and hydrometer. I suspect it's the cause of my gbta stress. Don't understand how it got so low but I'm going to raise it by evaporation.

If I evaporate the water will things increase on the test kit like alkalinity and calcium? Or do they remain the same?

Randy Holmes-Farley · Dec 25, 2014

Everything will increase (except pH).

Going from sg = 1.023 to 1.025, things will increase by a factor of 25/23 = 1.087

So magnesium at 1250 ppm will become 1359 ppm, assuming you just add more of the exact same water and allow it to evaporate.

Cory · Dec 25, 2014

Good to know. I suspected it would increase but had doubts. That's a big jump in magnesium. How about alkalinity? I'm sorry I don't understand the increase by a factor of.

I'm going to let the water in the sump drop, then when I get to the salinity I need ill top up the sump with full strength seawater.

Randy Holmes-Farley · Dec 25, 2014

25 (from 1.025) divided by 23 (from 1.023) equals 1.087.

So multiply everything by 1.087 if that is the rise you intend.

Alk at 8.0, for example, would rise to 8 x 1.087 = 8.7 dKH.

Cory · Dec 25, 2014

So I'm going to 1.026 so 26\23 = 1.1304

My all is 7.5dkh so it will raise to- 8.47dkh. And calcium will be about 450ppm from 400ppm.

Seems good?

Also how many gallons would need to evaporate provided I'm not adding any water? It's about 38 gallons total.

Cory · Dec 25, 2014

Do you think that my gbta is showing sighs of stress for the lower salinity?

Randy Holmes-Farley · Dec 25, 2014

Cory said:
So I'm going to 1.026 so 26\23 = 1.1304

My all is 7.5dkh so it will raise to- 8.47dkh. And calcium will be about 450ppm from 400ppm.

Seems good?

Also how many gallons would need to evaporate provided I'm not adding any water? It's about 38 gallons total.

Yes, that looks right, and you need to evaporate about 13% of the water volume, or 5 gallons.

Randy Holmes-Farley · Dec 25, 2014

Cory said:
Do you think that my gbta is showing sighs of stress for the lower salinity?

I don't know. People keep them that low OK, but it isn't optimal, IMO.

Cory · Dec 25, 2014

Some people say they can't tell others say he's stressed and bleached. Here's a pic, what do you think? Under kessil a 360n now.

Randy Holmes-Farley · Dec 26, 2014

Yes, it looks bleached, but I probably wouldn't attribute it to the low salinity.

Cory · Dec 26, 2014

Ok good to know. Your the second person to say it's not the salinity. Why wouldn't it be salinity? I know they live in shallow waters and bursts of rainfall would effect them. When I snorkeled in the carribean I was 4 meter deep water in an inlet and I saw many condagalactus sea anemones. The water was dirty with lots of algae too.

Have you ever heard of any sort of deficiency in sea anemones, like iodine?

Randy Holmes-Farley · Dec 26, 2014

I'd guess not the salinity because people keep them at that salinity OK (as long as it is fairly stable).

Cory · Dec 27, 2014

Okay. I was reading this article. I don't understand their measurement of salinity. It's a short article. Can you tell me if they are saying low salinity kills them or high salinity? If both at what salinity seems really bad?
http://www.new1.dli.ernet.in/data1/upload/insa/INSA_1/20005b7c_329.pdf

Randy Holmes-Farley · Dec 27, 2014

It survived at 15-42 ppt for several days, but not higher or lower levels. This was a short test.

Cory · Dec 27, 2014

What is that in SG or ppt? That was my confusion.

Cory · Dec 27, 2014

Oh never mind I see you posted that! Lol. I thought you posted that in percentages. So do you think lower salinity effects them? If my salinity really was as low as 30ppt (1.022sg), what was the mortality rate of this study at or around that? If you don't mind.