Check those refractometers!

copper · Jan 10, 2012

Long story short...Over the last few weeks my tank has been slowly deteriorating, corals dying, loosing color, staying closed , etc. I checked all the obvious tests and all are WNL It was getting to the point of just wanting to close the tank down. But 2 days ago I started mixing up a batch of make up water (25gallons) using reef crystals for the first time. When I had used 1/2 of the 50g bucket of salt and the specific gravity of it was only 2.016 the light bulb went off!! The refract is off! Hadn't recalibrated it it in over a year.
So, today I took it to AM and had it recaled, Thanks Jake , and Mel ( for the solution). OMG , the tank water is 2.035!!!! Surprised anything is alive at all. I will get it lowered slowly and hopefully see things recover.

cee · Jan 10, 2012

I do it every time I do a water change after learning the hard way too. 3.65 g Morton's Iodized salt to 96.35 g RO/DI or distilled H2O gives you 35 ppt on your refractometer. You can get a scale for not too much $$ that is sufficiently accurate and a wise investment IMO. In spite of what the instructions say, calibrating with pure water alone will NOT give you accurate readings.

cee · Jan 10, 2012

copper said:
OMG , the tank water is 2.035!!!! Surprised anything is alive at all. I will get it lowered slowly and hopefully see things recover.

Did you mean 1.035? 2.035 and everything would be dead. I don't even think saturated salt water could achieve 2.035 (I think it is around 1.2).

copper · Jan 10, 2012

Good catch Dave. It is 1.035 I Used to recal with every water change but got complacent when it never changed and stopped over a year ago. I now have some solution that mel made up.

Engloid · Jan 10, 2012

How close would it be to calibrate with pure water? Or is it simply going to be inconsistent?

cee · Jan 10, 2012

copper said:
Good catch Dave. It is 1.035 I Used to recal with every water change but got complacent when it never changed and stopped over a year ago. I now have some solution that mel made up.

Mel's solutions are spot-on 1.025!

cee · Jan 10, 2012

Engloid said:
How close would it be to calibrate with pure water? Or is it simply going to be inconsistent?

I've seen it off by as much as 0.005. Doesn't sound like much but 1.025 is a lot different than 1.020 especially if you're talking coral. If you ever want a cal solution I can mix it up in a couple of minutes at home.

Runner · Jan 11, 2012

Sounds like a good topic for (and a good thing to bring to) the next meeting.

EvilMel · Jan 11, 2012

cee said:
Mel's solutions are spot-on 1.025!

:wink:

I try!

I made them at the lab and dropped them off at AM for Jake to use/give out. If Coral Reef needed more and asked me, I would give them some too. They used to have some from me but I'm not sure if there are any left. I used to give everyone a tube of it when they bought a refractometer.

Man, I haven't checked mine in a bit. I will today though. But ding dang...I'm not sure if I've got any of the solution at home. hah hah. I will bring some from the lab though.

Janie, I'm really sorry to hear about your tank. If you need some frags to get started again, let me know! I'd be happy to help you replenish.