Reef Crystal CA & KH levels???

[duganderson]

According to aquariumwatertesting.com, RC basic elements are approximately, 340ppm Ca and 8.68 dkh of KH. I just tested a newly made batch of Reef Crystals made with RO water that was 78 degrees and 1.025 (BRS refractometer) and I got 400 CA (API) and 10 dkh of KH (API).

Any sense of which one is more correct or why my numbers are differerent?

I know people give API a hard time but I've heard many folks say the tests are accurate (and less expensive) for CA and KH.

[brandon429]

There was an article about three years back with this same skew when the author had everyone bring test kits both current and expired, but the focus was on expired to see how close they were. All test kits simply show a range. Since the API ammonia kit has known higher than usual readings thats no surprise the others might. Some people like API they just feel interpretations vary.


http://www.advancedaquarist.com/2012/6/chemistry

[hollister]

You cant test batches for anything other then salinity level. With all other water testing test main tank and in the morning around the same time. readings can change from daily tank activity.

[Michigan Mike]

I've always got 460 cal & 11dkh @ 1.026

[hogfanreefer]

Originally Posted by Michigan Mike

I've always got 460 cal & 11dkh @ 1.026

Mine has been very close to that (455 & 10.8). Using Salifert tests

[Bpb]

Funny this came up. I just did a whole write up on this same subject on my local forum. I just purchased a brand new bucket of Reef Crystals, and tested the first batch today.

I mixed the bucket up real real well, rolling and tumbling it to make sure nothing was settled down. I used fresh, 0 TDS RODI water to mix it. Mixed it for 24 hours. I'm not new to mixing salt, or my test kits. I've used them for a long time and after performing double tests back to back to ensure I didnt miss something here were my results:

Salinity: 1.026 (VitalSine refractometer, calibrated with pinpoint)
Calcium: 480 ppm (Red Sea Pro)
Alkalinity: 12.2 dKH (Red Sea Pro)
Magnesium: 1480 ppm (Red Sea Pro)

These levels were alot more buffered than I anticipated out of this salt. A little bothersome actually because I don't run my numbers that high in my tank, but as I only do 10% water change once monthly, I don't imagine its gonna screw anything up too bad.

The inconsistency in Reef Crystals is certainly disheartening. A friend who uses the same salt tested his bucket at 430 calcium, 8 dKH, and 1300 ppm magnesium, using the same testers. THOSE were the parameters I was hoping for.

To make matters even more inconsistent, I had been testing the final bag of a 200 gallon box I had purchased and been using for the past year. At 1.024 I was measuring 380 ppm Calcium, 8.2 dKH, and 1100 ppm Magnesium. Same testers and same mixing methods.

How can one salt brand be so wildly different from batch to batch?

[SUPERSTOCKRACER]

I got 12.0 dkh
calcium 480
magnesium 1440 @ 1.025

I switched back to regular IO Salt.

[Michigan Mike]

For people who don't dose or have softt/LPS tanks RC is decent enough but I have switched back to IO and kalk.

[duganderson]

Do folks think the variations in CA, KH and Mag in Reef Crystals is more due to test error OR actual variation in CA, KH and Mag in RC salt????

Why the switch to Instand Ocean for some folks? I've heard that IO is not as good as RC.

Also, does anybody know how to convert test results of CA, KH or Mg results on water at 1.025 vs 1.026 or would the difference be too small to mater????

[pete33]

Just did my first WC with RC last week (using IO). I never check my make up water but do check DT before and after. I thought maybe I could stop dosing for a few days after the WC but turns out my levels were not as high as I thought they'd be.

[sirreal63]

Originally Posted by duganderson

Do folks think the variations in CA, KH and Mag in Reef Crystals is more due to test error OR actual variation in CA, KH and Mag in RC salt????

Why the switch to Instand Ocean for some folks? I've heard that IO is not as good as RC.

Also, does anybody know how to convert test results of CA, KH or Mg results on water at 1.025 vs 1.026 or would the difference be too small to mater????

It can and will be both testing error and actual variations. If you are testing at 1.026 and your refractometer is not calibrated correctly, then there is no way to know what the levels actually are. API kits rely on matching up a color to a chart, but the variations in people's ability to see subtle color differences is always a problem. The other problem that happens is people do not stir the contents of the salt bucket before use, ingredients do settle and shift so it is very important to mix the salt the best you can before use.

There is nothing wrong with using regular IO, in fact some of the best reefs out there use plain old IO. RC adds vitamins and EDTA which is just not needed. The test results in the Chem forum are not that far off, considering their age.
http://www.reefcentral.com/forums/sh....php?t=1714505

IO mixes up fairly consistent for me and I have no problems with it. Whoever told you it was not as good as RC is not well informed.

[duganderson]

Originally Posted by sirreal63

It can and will be both testing error and actual variations. If you are testing at 1.026 and your refractometer is not calibrated correctly, then there is no way to know what the levels actually are.

When I was asking about test error, I meant test error in the Ca, KH or Mag. tests not in my salinity readings. I did used refractometer calibrated (calibration solution) right before it checked the salinity of the fresh salt water.

In your quote, are you saying that the exact level of salinity makes a big difference in leves of CA, KH, mg, etc? I would not think that 1.025 would make much difference in levels of CA, KH, Mg. etc. than 1.026. Is that that correct or do small changes in salinity change the CA, KH, etc. readings significantly?

[sirreal63]

The test error will vary, some kits have a better resolution than others, API is ok but not as accurate as Salifet or any of the other better quality kits. it is easier to see a color change than to match up colors on a reference card. Like most people I started this hobby with API but quickly went to Salifert, it is just easier to use and you don't have to try and figure out what color you are seeing.

If the salinity is accurate, there will not be a huge difference between 1.025 and 1.026. Where it becomes an issue is someone who calibrated with RO/DI instead of e correct solution, has a cheap refractometer that isn't accurate to begin with or is using a swing arm that has not been calibrated and could have a large difference in perceived salinity and actual, this will impact the readings as a mix at 1.040 is going to have a higher level of the big three than 1.020. This gets exacerbated by not mixing the salt before use, of the mix is not consistent then the levels will not be consistent. If separation has occurred and your mix starts out hi in alk, it could end up being very low at the end of the bucket.

We should always be testing our water before doing a water change. I know people frequently don't, but it is a good idea to know what you are adding before you add it and making corrections if needed.

[Reverend Reefer]

honestly, i found the same thing with IO-RC about a year ago. there was another thread, maybe on here, which discussed the inconsistencies with IO reef crystals. i remember people were proposing that there was a bad batch that year. either way, it was enough for me to just switch brands. i still haven't found one that is consistent and relatively affordable. i guess i might try plain old IO and start dosing again. for awhile, i was using Seachem's Salinity and that was the most consistent salt mix and i stopped dosing. however, Salinity was pricey, hard to find, and you had to follow sort of complicated mixing instructions.... i guess you gotta pay for the extra care they take in measuring each bucket.