The Puffer Forum

Its reading 1.0 right now. I know I have salt in there. I know not to move the salt up by more than .002 at a time to avoid killing the bacteria. Do these work okay? I know its nothing like a refractometer in terms of accuracy but I wanted a cheap, ballpark number. My F8's have been in the tank for a week and a bit.

Yeah, hydrometers are not the best thing to tell a 0.002 SG difference, especially close to the freshwater range. That's the exact the reason I got the refractometer. It's the most practical $25 I spent on the fish hobby.

Thanks. Should I just leave the salt as is then for now?

By the way, I like your photography. Looked at your flickr account the other day.

When I first started adding salt to my water, i realized that my tap water read "0.996" so I assumed that the indicator was probably off by 0.004. Check to see if that's your case. You can still try to increase the salinity in a very reserved way until you get a refractometer. The hydrometer makes it hard, but not impossible to tell an SG difference.
Btw, thanks for liking my photographs!

i hadn't thought to test the tap water. we have city water but makes me wonder about those with well water- salt and sump pump and all.

idid add a small amount of salt earlier and it registeted 0.002 higher after i let it sit for 10 mins or so.

Since you're using a hydrometer, calibrate it. I don't know how this is done, but it makes them much more accurate. Google some directions.

To calibrate a hydrometer, simply test the same sample of water with both a refractometer and your hydrometer. Note the difference, and factor that in when you test your water from then on out.

marksrush wrote:To calibrate a hydrometer, simply test the same sample of water with both a refractometer and your hydrometer. Note the difference, and factor that in when you test your water from then on out.

Although if you have a refractometer to begin with just use that!

Or you can get distilled water and test it in your hydrometer.....it should read zero. Then test your tap water, could read darn near anything. Keep that in mind when you add salt.

marksrush wrote:To calibrate a hydrometer, simply test the same sample of water with both a refractometer and your hydrometer. Note the difference, and factor that in when you test your water from then on out.

That is only good if the refractometer has been calibrated 1st. There is calibration solution available. RO water isn't always the best:
http://www.reefkeeping.com/issues/2006-12/rhf/index.php

God this is confusing..