Salinity spike

[Animal1969]

Hi all ,
I’m round a friends house helping him with his marine tank .
Just checked water parameters and his salinity is reading 1036 .ive tested it 3 times to make sure .
He’s panicking a bit as he has fish and a couple of corals . Birds nest and green Kenyan tree ,
Blue tang , 2 clowns . Firefish . Yellow wrasse . Pink goby .
It’s a 180 litre tank . No sump or protein skimmer ,
Running 1 large internal filter and an external filter .
1 surface skimmer .
He has an account with spotless water , so can get plain RO water 24/7 .
Thought I’d check 1 st would be it be ok to take some water out and replace with plain RO water
Thanks Dave

 

[I never finish anythi]

What are you using to check the salinity???

 

[Animal1969]

Refractometer .
I’ve reset it before every test .
Thanks

 

[I never finish anythi]

If everything looks happy and is acting normal , I would bring it down slowly not to shock the inhabitants.
I'd go down to 1.035 one day then 1.034 the next and so on until you get to 1.025 . And get it double checked in the meantime just to be sure.
Goodluck

 

[Animal1969]

Ok thanks for your help .
I did say same to him but when it’s someone else’s tank I always double check before committing to giving advice unless I’m 110% sure .
Thanks again
Dave

 

[Gtinnel]

Refractometer .
I’ve reset it before every test .
Thanks

What do you mean reset it before every test?

Before having them make any changes to the tank it’s important to be positive that the tank is at the salinity that you think it.

 

[Animal1969]

I changed 5 litres of water about 3 pm today for plain RO .
Can I change another 5 litres now .

Thanks
Dave

 

[Animal1969]

What do you mean reset it before every test?

Before having them make any changes to the tank it’s important to be positive that the tank is at the salinity that you think it.

What I meant was checked it was zero before each test with plain RO water

 

[Randy Holmes-Farley Verified Community Expert]

What I meant was checked it was zero before each test with plain RO water

Just to be sure, I'd also check it with a 35 ppt standard. You can make one yourself using table salt.

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

In order to provide a standard for refractometers, a solution whose refractive index is similar to normal seawater is required. Seawater with S= 35 has a refractive index of 1.3394.1 Likewise, the refractive index of different sodium chloride solutions can be found in the scientific literature. My CRC Handbook of Chemistry and Physics (57th Edition, Page D-252)4 has such a table. That table has entries for 3.6 and 3.7 weight percent solutions of sodium chloride that span the value for normal seawater. Interpolating between these data points suggests that a solution of 3.65 weight percent sodium chloride has the same refractive index as S=35 seawater, and can be used as an appropriate standard (Table 2).

This 3.65 weight percent sodium chloride solution can be made by dissolving 3.65 grams of sodium chloride in 96.35 grams (mL) of purified fresh water. That amount roughly corresponds to ¼ cup (73.1 g) of Morton's Iodized Salt dissolved into 2 liters (2000 g) of water (giving very slightly more than 2 L of total volume).

For a rougher measurement in the absence of an accurate water volume or weight measurement:

1. Measure ¼ cup of Morton's Iodized Salt (about 73.1 g)
2. Add 1 teaspoon of salt (making about 79.3 g total salt)
3. Measure the full volume of a plastic 2-L Coke or Diet Coke bottle filled with purified fresh water (about 2104.4 g)
4. Dissolve the total salt (79.3 g) in the total water volume (2104 g) to make an approximately 3.65 weight percent solution of NaCl. The volume of this solution will be slightly larger than the Coke bottle, so dissolve it in another container.

 

[Animal1969]

Ok thanks ,
But can I do one more change of 5 litres. Plain RO today .
Or should I wait till tomorrow
Thanks
Dave

 

[Randy Holmes-Farley Verified Community Expert]

Ok thanks ,
But can I do one more change of 5 litres. Plain RO today .
Or should I wait till tomorrow
Thanks
Dave

I'd do that only once a day.

One 5 L change would drop a sg of 1.0290 to 1.0282, which seems enough in one day.

 

[14 foot reef]

Hi all ,
I’m round a friends house helping him with his marine tank .
Just checked water parameters and his salinity is reading 1036 .ive tested it 3 times to make sure .
He’s panicking a bit as he has fish and a couple of corals . Birds nest and green Kenyan tree ,
Blue tang , 2 clowns . Firefish . Yellow wrasse . Pink goby .
It’s a 180 litre tank . No sump or protein skimmer ,
Running 1 large internal filter and an external filter .
1 surface skimmer .
He has an account with spotless water , so can get plain RO water 24/7 .
Thought I’d check 1 st would be it be ok to take some water out and replace with plain RO water
Thanks Dave

Is reef tank owner out of town, or there ?

What is the salinity history, is there any records of where the Salinity has been over the past couple months ?

 

[Animal1969]

His reading was 1036 .
He’s at home and normally on the ball with it all .
He been ill and in and out of hospice so his tank has been 2nd to his health .
He’s just asked me to help with it yesterday .
I’m just trying to save his tank mates .
Hence the 5 litre water change earlier , was wondering if another 5 litres would be ok . Then same tomorrow and so on depending on readings .

 

[Animal1969]

He hasn’t kept readings ,
He just does tests wrights down results and if ok chucks away the paper he wrights it

 

[14 foot reef]

His reading was 1036 .
He’s at home and normally on the ball with it all .
He been ill and in and out of hospice so his tank has been 2nd to his health .
He’s just asked me to help with it yesterday .
I’m just trying to save his tank mates .
Hence the 5 litre water change earlier , was wondering if another 5 litres would be ok . Then same tomorrow and so on depending on readings .

See @Randy Holmes-Farley comment above, you are safe as can be to follow Randy's advice on anything reef related.