Salinity 1.020/1.0210

NaturalGothic
Member
Hey guys!
I set up a 10 gallon nano reef tank less than a week ago. I don’t have corals, just inverts and one percula clownfish. I purchased R.O. Saltwater who’s parameters are: Ph 8.3, Salinity 1.0230. Everything went great, inverts doing well, Clown just fine. However, I noticed a dip in my salt levels. It went from 1.0230 to a 1.0190; I hadn’t added any water since setting it up so I don’t understand how that happened. (I have a glass lid too so not heavy evaporation.) In an effort to raise salinity, I topped off my tank with 2 quarts conditioned tap water and 1/4 cup instant ocean salt. I did my best to mix it but not all of the salt dissolved and I didn’t notice until it was in my tank. My water is now reading 1.0210. Anyone know what caused the dip? I’m sort of at a loss when it comes to that. How do I maintain a 1.0230 salt level? Also, when will the salt grains dissolve in my tank?
Thanks!
 
ChrissFishes01
Member
Typically you'll see salinity rise as water evaporates - the only way for it to fall is by freshwater being added.

Are you using a refractometer or a hydrometer to measure your SG? A refractometer needs to be calibrated with calibration fluid. If your refractometer is calibrated correctly, the fluid will read 35 PPT (about 1.026). If not, most refractometers have a screw that allows you to adjust it correctly. In a pinch, you can use distilled water, but it'll be a bit less accurate. If you're using a hydrometer, just ensure that it's well-rinsed and bubble-free. Sit it on a level surface. Then pray - I've never had good luck with hydrometers. Good enough for brackish and fish only tank, but probably not for a reef.
 
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NaturalGothic
Member
HarrisonAquatics said:
Typically you'll see salinity rise as water evaporates - the only way for it to fall is by freshwater being added.

Are you using a refractometer or a hydrometer to measure your SG? A refractometer needs to be calibrated with calibration fluid. If your refractometer is calibrated correctly, the fluid will read 35 PPT (about 1.026). If not, most refractometers have a screw that allows you to adjust it correctly. In a pinch, you can use distilled water, but it'll be a bit less accurate. If you're using a hydrometer, just ensure that it's well-rinsed and bubble-free. Sit it on a level surface. Then pray - I've never had good luck with hydrometers. Good enough for brackish and fish only tank, but probably not for a reef.
It’s a coralife hydrometer; brand new. I let it sit with my tank water for 24 hours just like the directions say. Are refractometers really that much better for a reef tank?
 
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NaturalGothic
Member
The only time I removed water from the tank was to acclimate my critters. I hadn’t take or added water prior to that.
 
ChrissFishes01
Member
NaturalGothic said:
It’s a coralife hydrometer; brand new. I let it sit with my tank water for 24 hours just like the directions say. Are refractometers really that much better for a reef tank?
IMO, yes.

The problem with hydrometers is that they don't read true in the first place - most of them have a slight offset. One might read 0.001 high, while the next one (of the same model) will read 0.002 low. So checking it with an accurate refractometer should probably be done so you know how much to offset your hydrometer.

Another issue is that there's a lot of room for error. A small bubble, an uneven table, or even a sticky arm can cause readings to be all over the place. Keeping it super clean and having a known level surface can help, but won't solve those problems. As for bubbles on the arm, if you fill it super slowly in the tank, it can help make sure less bubbles are formed while filling it.

They're not unusable or anything - I use one to double check my refractometer every now and then. My FOWLR tank is in hyposalinity right now, and I'm using my hydrometer as a sanity check, as 0.001 up or down can kill the fish or make the treatment useless. That said, when my water is testing exactly 1.009 on two freshly-calibrated refractometers, my hydrometer reads 1.007. If I was basing it on my hydrometer, I could be slowly killing some of my more delicate fish.

I personally used one of the cheaper ATC refractometers off of amazon for years before I got something else. Worked just fine for me - just have to calibrate it often and keep it clean.

Amazon.com : Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium 0-100 PPT with Automatic Temperature Compensation : Pet Supplies
 
  • Thread Starter
NaturalGothic
Member
HarrisonAquatics said:
IMO, yes.

The problem with hydrometers is that they don't read true in the first place - most of them have a slight offset. One might read 0.001 high, while the next one (of the same model) will read 0.002 low. So checking it with an accurate refractometer should probably be done so you know how much to offset your hydrometer.

Another issue is that there's a lot of room for error. A small bubble, an uneven table, or even a sticky arm can cause readings to be all over the place. Keeping it super clean and having a known level surface can help, but won't solve those problems. As for bubbles on the arm, if you fill it super slowly in the tank, it can help make sure less bubbles are formed while filling it.

They're not unusable or anything - I use one to double check my refractometer every now and then. My FOWLR tank is in hyposalinity right now, and I'm using my hydrometer as a sanity check, as 0.001 up or down can kill the fish or make the treatment useless. That said, when my water is testing exactly 1.009 on two freshly-calibrated refractometers, my hydrometer reads 1.007. If I was basing it on my hydrometer, I could be slowly killing some of my more delicate fish.

I personally used one of the cheaper ATC refractometers off of amazon for years before I got something else. Worked just fine for me - just have to calibrate it often and keep it clean.

Amazon.com : Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium 0-100 PPT with Automatic Temperature Compensation : Pet Supplies
Thanks hun! I think I’ll buy one once I recover from the pretty penny I spent lol I just want to know if my inverts be ok. The other day, I added 2 Tbsp slat directly to the tank (I didn’t think to dissolve it) and my poor nassarious snails flipped out for about a minute then went back to normal. They seem fine now but it made me worry.
 
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