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Unread 10/04/2017, 10:07 PM   #11
dkeller_nc
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Join Date: Mar 2013
Location: Central NC
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Yes, something is definitely "off" if you mixed a new batch of Reef Crystals to the correct specific gravity and you got those numbers. RC definitely can have some variations batch-to-batch, but an alk of 7 dkH is really hard to explain. In fact, RC is known for having alkalinity that's way too high, and doesn't enjoy a good reputation from the SPS keepers for that reason.

But you should still entertain the idea that your refractometer is out of calibration, because a low specific gravity would explain your salt mix numbers. Keep in mind that a refractometer must be a) made for ocean water (many are scaled for brine) and b) calibrated with a 1.026 calibration solution. Many refractometers will tell you to "calibrate" the instrument with RODI. That won't do it, especially if it's a brine refractometer.

As far as temperature is concerned, 74 deg F is definitely not going to be good for the animals long-term, though they will certainly be OK for a few days. There's a lot of debate about the "right" temperature for coral reef animals, but most will tell you to keep it between 76 deg F and 80 deg F. Too warm is far worse than too cool, btw - anything above 82 deg F is getting into the danger zone. You've several options for accurate temp measurement that won't break the bank. Lifeguard Aquatics little time 'n temp units are quite accurate, and are calibrated from the factory. You can also purchase an accurate laboratory-grade thermometer off of Amazon that should be under $20. With this, you can check whatever electronic instrument you already have, and simply apply an offset.

With respect to alkalinity adjustments, most will advise you that a 2 dKh jump all at once is a bit much - most will recommend no more than a 0.5 dkH adjustment every 24 hours.

Keep in mind the adage that nothing good happens quickly in a reef tank, and apply it to your water chemistry and temperature adjustments. Definitely don't raise the temperature suddenly - that can cause a cascade of bad things that can cause a tank to go downhill fast.

With respect to test kits, a lot of us like Salifert for high accuracy, ease of use, and cost effectiveness. Others may recommend Elos test kits, and Red Sea still has quite a few fans. API doesn't exactly get rave reviews, although in relatively skilled hands they can give accurate results. You can buy Salifert test kits from several 'net dealers and have it by this weekend, one example is Bulk Reef Supply.


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