Anyone else get RO\DI salt water at The Fish Store

[willtel]

I have been buying all my top off and water change RO\DI from The Fish Store in Buckhead (it is close to home and I only have an 18 Gal). The Fish Store claims that the water is mixed to 1.025 with Kent Marine salt but every time I do a water change I have to add fresh RO\DI water to bring the salinity down to 1.025. Anyone else have this issue? I can't wait to get that refractometer at the next meeting so I can be sure what is really going on.

[cyberchef]

What are you using to read the salinity. It could very easily be your hydrometer, if that's what your using. You might check with them to see what they use to determine the salinity. If it's a refractometer, then take your "hydrometer" in with you and ask them to do a comparison between the 2 so you will know where your is calibrated vs what it reads.

[willtel]

I have two seatest hydrometers and they do read different but both read a little higher than 1.025. I have seen The Fish Store test the water before they fill my containers and they use the same thing. When I get my refractometer I will know for sure.

[GeoJoe]

be careful when buying from them, as I have noticed major fluctuations in their salt content. Weekend employees may not be as observant as full time guys.

ask Porter.... he'll tell you all about it (for hours)

[Joel]

and hours and hours and hours and...........

[cyberchef]

If thier using a hydrometer and not a refractometer, then IMHO that is poor business practice and adds to the list of things that can make a store unreliable. I've seen first hand how much difference there can be between 2 hydrometers, of the same brand, with the same water sample. Since they are closed on Tuesdays, going there for anything, as far as I'm concerned, is a mute point since 98% of the time I'm in Atalanta it's on a Tuesday.

[Ray1214]

A good time to get in on the refractometer power buy...

[ckreef]

If they are using a hydrometer and your using a hydrometer then most likely thats where the difference is.

I have taken my refractometer to many different homes/LFS and tested against their hydometer. I have not found one hydrometer to be accurate.

To be fair to hydrometers most are not callibrated to 82 degree water temp (and I know they say they are temp compensating --- lets not believe everything we read). I have a book that explains hydrometers and temp calibration and has the modification charts that you would need to transpose your hydrometer reading into a reading valid for whatever water temp you have.

When doing these tests I also took a temp reading. I brought the data home and ran it through the charts and most of the time the ending salinity (after the modification charts) matched the refractometer. (but not all hydrometers --- on an individual basis).

Finally before anyone asks the book is "Fish and Invertebrate Culture" second addition by Stephen Spotte. This is a fairly technical book about marine tanks and is the only book I have ever seen w/ the modification charts. I don't believe you can find it currently on the market but I could be wrong. It took me awhile to find this book and that was 12 years ago.

Charles

[georgiajams]

I'm sure someone thought of this, but I'd suggest we have a mass "how to calibrate our new power buy refractometers" after they come in.

Is it as easy as putting a drop of RO on the lens and twisting a knob/screw til it reads 1.0?

-Chris

[sally]

Is it as easy as putting a drop of RO on the lens and twisting a knob/screw til it reads 1.0?

-Chris [/b][/quote]

Yes, it is that easy!

[Phantom Phish]

Ditto, thats all it takes (allthough the directions on my unit says to use three drops). In fact I usually test my tank water first and then rinse and test with the RO-DI water. As long as the RO-DI water reads 1.000 (and it always does), I accept the value I got for my tank water. This just saves me having to rinse and clean the refractometer a second time.