Why does reef crystals only have 320 Ca?
- Thread starter StrategicReef
- Start date
Here is an update. When I mixed it last night, I way overshot the SG. I usually make SW 40G at a time. I dumped out some and added more RO to get it right.
I retested this am and got ~ the same ~ 340 for the ca reading. Because of the way I had mixed it, I wanted to be sure that wasn't the problem. I made up a new 1G and was more careful. This one reads 370, which is still lower than the 420 I usually get. I also tested alk and mg.
ca 370 Salifert
alk 12 API
mg 1110 Salifert
The MG is definitely lower than I usually see as well. I'm going to let this mix through the day and retest later on.
This is a 160G bucket that was shipped to me from DR F&S on 7/31/2007.
This is a bummer. Until now, RC was a very nice, balanced salt at an attractive price. I wonder what else has changed.
I retested this am and got ~ the same ~ 340 for the ca reading. Because of the way I had mixed it, I wanted to be sure that wasn't the problem. I made up a new 1G and was more careful. This one reads 370, which is still lower than the 420 I usually get. I also tested alk and mg.
ca 370 Salifert
alk 12 API
mg 1110 Salifert
The MG is definitely lower than I usually see as well. I'm going to let this mix through the day and retest later on.
This is a 160G bucket that was shipped to me from DR F&S on 7/31/2007.
This is a bummer. Until now, RC was a very nice, balanced salt at an attractive price. I wonder what else has changed.
Mike O'Brien
New member
I ordered a new salinity standard yesterday to recheck my refractometer. But how far off would it have to be to cause a 100 ppm difference. I'd tend to think it would be so far off that the corals would not be happy.
To make 1300 ppm magnesium look like 1200 ppm, the salinity would have to be off by (1300-1200)/1300 = 7.7%. So instead of 35 ppt you'd have 32 ppt, or instead of sg = 1.026 you'd have 1.024.
Mike O'Brien
New member
Randy, What about calcium. I'm getting 300 ppm and others have 420.
That would be a whopping 25% salinity difference. Unlikely you could have that. 
Mike O'Brien
New member
I got 28.6 % if that is still the right math ?
Mike O'Brien
New member
Cool. Thanks 
I rounded to 400 ppm.
StrategicReef
New member
What the heck, can you post your ALK too of new RC mixed water.
Mine has always been around 4-5 MEG/L or *2.8 = 14DKH
I am looking for the graph with the curve of ALK vs CA from reefkeeping so I know what CA level is suitable for this alk. it would be in the 420+ range I imagine
Mine has always been around 4-5 MEG/L or *2.8 = 14DKH
I am looking for the graph with the curve of ALK vs CA from reefkeeping so I know what CA level is suitable for this alk. it would be in the 420+ range I imagine
The optimal calcium level is largely unrelated to the alkalinity. I'd target 2.5-4 meq/L (7-11 dKH), almost regardless of what calcium level is targeted.
The only time they are related is if you are trying to raise or lower them together, such as by adding equal parts of a two part, or allowing corals to drop both by using them up.
The only time they are related is if you are trying to raise or lower them together, such as by adding equal parts of a two part, or allowing corals to drop both by using them up.
acrylic_300
New member
Just checked mine
SG 1.0255 (under shot it a bit) IO swing arm
PH 7.9 (only mixed for 10hrs) API
Alk 12.5 API
Ca 360 API
Seems like a good thread to make sure your numbers are ON...If you use RC.
I have no complaints....at least it is consistent.
SG 1.0255 (under shot it a bit) IO swing arm
PH 7.9 (only mixed for 10hrs) API
Alk 12.5 API
Ca 360 API
Seems like a good thread to make sure your numbers are ON...If you use RC.
I have no complaints....at least it is consistent.
acrylic_300
New member
Like jdieck said....it smells different. It has something different in it and it mixes up less clean.
It has a rich smell like minerals or something. But yes it seems to have the same parameters.
It has a rich smell like minerals or something. But yes it seems to have the same parameters.
Billybeau1
Premium Member
I will bet your swing arm is off. You are likely mixing at a lower s.g. than you think, causing the low calcium reading.
I tested a new batch of RC just the other day and at 1.0264 (35 ppt) it registered 420ppm calcium. As it always does.
Those of you seeing other readings are either mixing wrong or have faulty test kits IMO.
Mike O'Brien
New member
Billy, I think I can speak for all of us when I say that either your calcium kit is bad or you're refractometer is off by about 25 %.
Mike O'Brien
New member
Is anybody else starting to think that Michael Del Prete is right now ?
