Reef Salinity

[LauraDlite]

During my trip to the Great Reef Barrier I noticed the water salinity off shore was around 1.028 sg. From what i gathered from this board most people keep their salinity at 1.025sg. I wonder if the salinity difference has any long term affects on corals? Thanks.

 

[greenbean36191]

1.0264 is just the average value for reefs worldwide. There's nothing magical about that number though. Reefs vary temporally and spacially from about 1.024-1.032. There's no evidence that any particular value in that range poses any additional benefit or harm, which is why the average value is usually recommended.

On certain occasions, values can even exceed that range, though at higher and lower values some of the more delicate species (echinoderms in particular) do begin to have trouble. Quickly changing values can be problematic for some species as well.

 

[seapug]

In my experience, real sea water is typically in the 1.027-.030 range. As greenbean said, it's really about stability within the acceptable range that our creatures will tolerate, but keeping it on the higher end will provide an increased concentration of minerals and trace elements that can improve the health and growth rates of corals, inverts and fish.

 

[Rhizo]

I'm with them up there. Normally in the higher 25 and 26 area. If you happen to wet skim sometimes I'll see it come down to the 23 or 24 area. No ill effects up to date.

 

[andygb54303]

1.025

 

[snorvich]

Likewise. I try to keep mine at 1.0264 but it creeps down wards over the 3 weeks in between water changes. Are you using a refractometer?

 

[LauraDlite]

I was using a floating swing arm hydrometer calibrated with distilled water. I didn't have a refractometer at that time.

 

[cloak]

I'm starting to think that the SG and temperature might be one in the same. 75-86?

 

[snorvich]

I strongly suggest you get a refractometer and calibrate it with pinpoint solution. Hydrometers are consistent but not accurate.

 

[JohnnyBassMan]

+1 for (Hydrometers are consistent but not accurate.)

I have both, well a friend has refractometer, and when his refractometer states 1.025 my hydrometer states 1.026 every time. So consistent yes.

 

[madadi]

i keep mine at 1.026

twice i let it creep up to 1.030 over the course of a few weeks, and even months, and most of my SPS browned out on me with minimal polyp extension and noticeable STN. im calibrating my refractometer more often now and keeping a closer eye on my salinity at least once a month.

 

[Capt_Cully]

Just a question, but doesn't particulate matter in the water increase the SG. Don't natural reefs have alot more nutrients in the water collumn? They have the luxury of massive water movement/exposure that we couldn't possibly replicate in our captive reefs. Keeping nutrient levels that high in a closed system would cause all kinds of problematic waste build up.

I've seen this quote quite a few times "A cubic meter( equivalent in water volume to about a 200g tank) on the Barier Reeef receives a million gallon water change per day"

Anyway, is it true this would cause the SG to be higher???

 

[greenbean36191]

Just a question, but doesn't particulate matter in the water increase the SG.

No.

Don't natural reefs have alot more nutrients in the water collumn?

It depends. Which nutrients are you comparing between which tank and which natural reef?

A cubic meter( equivalent in water volume to about a 200g tank) on the Barier Reeef receives a million gallon water change per day

This quote is a perfect example of a number someone pulled out of thin air. A million gallons of water per day in gpm is more than what a fire hose puts out. Also, it's extremely hard to measure flow volume on the reef. It's almost always measured as flow speed. Don't believe everything you read.

 

[Capt_Cully]

Fair enough! on the comparison.

But, I thought SG was dependent, or a measure of the density of a liquid. Therefore, if there's more particulate matter in a volume of water, would that not increase it's SG, not necessarily the Salinity?

Working in medicine, people who have renal insufficiency do not filter out things like proteins and glucose as well as someone with normally functioning kidneys. These things pass into their urine, which as a result has a higher SG.

 

[cloak]

Perfect! Almost nine years. 75-86.

 

[Rhizo]

Cloak is that your mix container?

 

[kevantheman35]

the marked "good" range on my coralife hydrometer is 1.020-1.023 whats with that?

 

[cloak]

<a href=showthread.php?s=&postid=14232310#post14232310 target=_blank>Originally posted</a> by Rhizo
Cloak is that your mix container?

It was just a cup of water, right out of the tank.

 

[LauraDlite]

<a href=showthread.php?s=&postid=14230742#post14230742 target=_blank>Originally posted</a> by Capt_Cully
Fair enough! on the comparison.

But, I thought SG was dependent, or a measure of the density of a liquid. Therefore, if there's more particulate matter in a volume of water, would that not increase it's SG, not necessarily the Salinity?

Working in medicine, people who have renal insufficiency do not filter out things like proteins and glucose as well as someone with normally functioning kidneys. These things pass into their urine, which as a result has a higher SG.

Capt, you have bought up a very interesting point.
I would also like to know if added nutrients/chemicals will affect the SG value of a refractometer/hydrometer. Maybe i should post in the The Reef Chemistry Forum also?

 

[Flipper62]

<a href=showthread.php?s=&postid=14232000#post14232000 target=_blank>Originally posted</a> by cloak
Perfect! Almost nine years. 75-86.

WOW......I haven't used...or seen one of then in a long time. I thought every stopped using the glass bobber when President Reagan left office......LOL