Help with Red Sea Calc test

[Brian1f1]

Hello,
I’m trying to measure my calcium. Does anybody know what I might be doing wrong to get an obviously wrong low reading of 75? I did it twice, used the right amount of water, the right amount of drops, the right powder. I get the right start color, but I can only add .15ml of titration fluid before it goes to the finished color. That can’t be right... but I can’t figure it out. Salinity is 1.026, alk is 11.2. What gives?

 

[pluikens]

Have you ever tried a second test kit, Red Sea or otherwise? Whats the expiration date on your test kit? Do you have an LFS that will test for you to either corroborate or disprove? Do you shake up reagent A before dropping, level off the scoop of reagent B when measuring, shake up the titration reagent before filling your syringe? Are you shaking up your sample after adding each reagent? This may be silly but I have to ask: I've seen the syringes that start at 0 at the tip and some that start at 1. Are you positive you're adding .15 ml of solution and not .85 ml?

 

[Randy Holmes-Farley Verified Community Expert]

Maybe there's a problem with the reagents, but i don't see any obvious issue, and you are right that 75 ppm is extremely unlikely.

 

[Brian1f1]

Have you ever tried a second test kit, Red Sea or otherwise? Whats the expiration date on your test kit? Do you have an LFS that will test for you to either corroborate or disprove? Do you shake up reagent A before dropping, level off the scoop of reagent B when measuring, shake up the titration reagent before filling your syringe? Are you shaking up your sample after adding each reagent? This may be silly but I have to ask: I've seen the syringes that start at 0 at the tip and some that start at 1. Are you positive you're adding .15 ml of solution and not .85 ml?

I don’t have a second test kit. The test is new, but I didn’t see if maybe BRS shipped me an old kit, I’ll check. Nearest LFS is 45 minute drive, not sure if they test... that’d be a last resort, but possible. I did not shake up regent A before dropping, I was following the instructions carefully, didn’t see that, will try. I did use a level scoop of powder. I did not shake up the titration regent, it didn’t say to do that, but I will try. Finally, yes, I’m sure, I barely added any regent at all, 85% remained in the syringe, both times.

 

[Brian1f1]

Maybe there's a problem with the reagents, but i don't see any obvious issue, and you are right that 75 ppm is extremely unlikely.

Yes, especially because I used RPM and Ken’s salt, and I’ve changed out at least 40% since I started. The tank is only 3 months old, and my corals are thriving. PH is 8.2, phosphorus is .25 (hoping this goes down via kalk and large refugium, or maybe it isn’t a problem?). Nitrate is 2.5. Alk last night was 11.2. I haven’t tested calcium. Since the tank is new, so I don’t have any number besides the 75. I have a Reefer 525, running to its sump in the basement which is functioning entirely as a refugium and sort of algae scrubber (one compartment is just growing hair algae, the other has chateo), it drains to a 150 gallon rubber maid, mostly filled, so I’m sure the calc couldn’t have been depleted by my mostly lps frags.

I have a large ATO that I have kalk in at a little less than half saturation. That is probably why my Alk is 11.2, which is fine, I think given my parameters. I was actually testing because I wanted to ensure my calc hasn’t been driven too high!

Edit: I do currently have what I think is a mild diatom outbreak. Coats the sand lightly, only takes a few hours after I disturb it to come back. Rocks have it too, no strands, just brown and right to the rock, doesn’t blow off with a baster from rock. Is not harming coral or very obtrusive, don’t know if that will go away on its own or is tied to my parameters.

Thanks for all your help!!!