Help with salinity and hydrometer use

I know this is a probably a silly newbie question but here goes:

As the water starts to evaporate in the tank does the salinity rise before adding more water? I had my 90 gallon setup and running at 1023 and i was doing a water change today and got the water i was going to put back into the tank at 1023 to add then i just thought to check my display tank to make sure that it matched exactly and it read 1027!!! So I am asking if it is my hydrometer (cheap plastic) or if it is due to some evaporation. Fish seem fine THANK GOD! And how slow should i go about bringing the water back down to safe levels?

Thanks in advance!

 

salt doesn't evaporate really. only the salt creep you see pretty close to the tank but thats really nothing.

so yes salinity does increase from evap

 

My 75 evaporates 1 gallon a day. How much are you adding for evaporation? Hydrometers can be insanely inaccurate. Before I bought my refractometer my Hydrometer always said i was in between 1.023-1.025, my first test with my refractometer was 1.030, I freaked cause I was using the hydrometer for 2 years.

 

:-[This scares me a bit. I still use the same hydrometer after 2 years.

 

i have both refractometer my Hydrometer. i mainly use the refractometer now, but when im in question. i use both. i can tell you each time i test with the hydrometer. its dead on. its a oceanic brand hydrometer.
the local fish store tested my water and told me my salt was off and my new hydrometer was wrong ..that it was off by 4 that thiers was correct ....well.... it wasn't it was their coralife hydrometer that was wrong! this i found out after believing them and throwing my tank out of wack. and as a result it killed my cleaner shrimp...thats when i bought the refractometer. salinity is to important to mess with. get a refractometer.

 

Yes, salinity rises when water evaporates. Keep your refractometer calibrated, and there's no reason to use a hydrometer as backup. A refractometer is so much more accurate, that any difference b/w the two devices will only show the innacuracy of the hydrometer.

 

Seatest swing-arm hydrometers are very suitable for use but other brands might or might not be and need to be checked against a certified calibrated hydrometer to know, especially the DEEP SIX one.
These plastic swing-arms need special care to keep them doing a reasonably accurate job of measuring s.g. though.
First, they need to be soaked overnight in white vinegar about once a week to dissolve particles that adhere to the swing arm and cause errant readings. Obviously they need to be well rinsed afterword.
Second, they need to be acclimatized before an accurate reading can be obtained as the initial readings when first taken will be high.
I take about 3 readings minimum before I'm satisfied that I have a decent reading and then take another just to verify. Be sure to wait a bit until the arm has really settled.
I then rinse the hydrometer and go to each of the other tanks in turn and can obtain a reading right off without this acclimation process again.
Once it dries, it needs the acclimation again.
If you don't like doing that, then you can buy a spectrometer and calibrate in in the range you intend to use it.
If you are looking for accuracy though, you need to use a certified calibrated hydrometer in a columnar cylinder, or buy a conductivity meter.
For those freaking out at suddenly finding water at 1.027 or 1.030, there is no need because it isn't that far off of ocean water which is considered to be 1.0264 on average.
If you are running at 1.023 then you are already running your tank at an artificially low standard.

 

First, there are no silly questions concerning your aquarium, if you don't know something...that is why we are all here.

This event mentioned above has repeated itself thousands of time. The same thing happened to me. If you have the $40-50 buy a Refractometer. You spend that much on one coral or fish.

 

I agree!! When I first started, the LFS sold me that stupid hydrometer that took me 20min to get a test result. I'd spend my time, tapping to get the air bubble off the reader arm so I could get an accurate (LOL I said hydrometer & accurate, not possible) reading.

I then went to another LFS that all he does is Saltwater Reef. I brought him a water sample, of course my salinity was off. He ask me how I was testing. I told him a hydrometer (all nice & proud I was). He began to chuckle, he showed me a refractometer. He tested my water again, because I was looking in his store when he tested it the first time. It gave him a result in seconds!! Perhaps folks on here didn't hear me, SECONDS!!!!! I then asked him, that must cost a lot. He stated is $49.99 a lot & that was the BEST $50.00 I have every spent in this hobby, PERIOD!

Sorry, about the blabbering. ;D I have never calibrated mine since he did it at the store. I check it every month with RO water and it's always at zero. Then again, I treat it like fine china. I wipe it dry & wipe it again twice with RO water & dry it again, then place it back in it's case.

 

i agree that the refractometer is the way to go. maybe i worded it wrong.

all i was trying to say is some hydrometers are way...way off. and cant be trusted. but i found the oceanic to be dead on.