Sg And Ppt

[Bloo]

I just wanted to say my refractometer works great and Dave (the eBay seller) posted it to me asap. It's easy to use and understand (for a newbie!). Calibration etc. very straightforward.

Just a question for you guys. How do you deal with evaporation and getting the concentration levels equal again ? (I feel like a complete newbie )

 

[Aquascaper]

As water evaporates from the tank you replace it with RO/DI water. Checking the SG weekly will ensure that the level doesn't vary too much and when you do partial water changes you can make any adjustments necessary. To be honest though i've never had an issue with it and the only way I can see it being a problem is if you have excessive salt creep.

 

[Opcn]

You were correct about 35 ppt being full strength salt water bloozoo2

nmonks- many marine fish do spend parts of there lives in brackish water, but al marine fish spend parts of there lives in marine waters, unfortunately even a 5% error can kill some of themore delicate critters in our tanks in a matter of days, while in the brackish section its perfectly alright to talk about big errors being peach here in the marine tank it needs to be made clear at every step of the way that that is not kosher and will result in death of livestock, surely you realise that.

 

[steelhealr]

I just want to focus one thing mentioned earlier by Navarre. The main problem with plastic hydrometers is that the slightest bubble that forms on the swing arm can throw off your reading. That makes them a little finicky. But...goes along with what nmonks stated....they, like our refractometers, must be periodically calibrated to get the best reading as possible. I calibrate my refractometer about once a month against RO water.

Remember, using any scientific instrument involves consideration of several factors including accuracy, precision and reliability. Deciding what is important to your tank and biotope will help you decide how to measure your specific gravity. I will say that I continually learn here and I thank nmonks for his comments about variability in salinity with regards to brackish fish. SH

 

[Bloo]

One more question I remembered - do you have a recipe for x amount of salt to x amount of water ?
The bag doesn't say anything, so I just had to keep adding (and letting it stand a bit) before taking readings (obviously before the zoes went in). It wasn't too hard to get it bang on 35ppt but there must be an easier way ?

 

[steelhealr]

It actually may vary between salt mixes. I know with my reef salt that 5 heaping cupfuls of salt in 5Gs of water brings me right in at 1.025. SH