Calcium spike after reef snow???

[nomad6]

Dosed brightwells reef snow recommended dose for 25 gals in my 30 cube and tested a few days later. Spiked ca and lowered alk. Calcium sitting at ~508 ish Hanna tested and alk dropped under 9 dkh. Any explanation and recommendations on lowering calcium (baking soda?) would be greatly appreciated. Only a few frags in there did not mess with major elements or water chemistry. Only chemistry I mess with is nutrients as they continue to bottom out or stay relatively low. Have some small sps frags/ 3 colonies, caulerpa and other macros, few hermits, snails, damsel and 6 line. Have a pocillopora showing stress tissue die off in shaded areas where they was non before. Thanks!

 

[nomad6]

Ph unchanged

 

[nomad6]

Using Red Sea pro salt not dosing anything for ca/ alk

 

[Randy Holmes-Farley Verified Community Expert]

I suspect you are getting false high readings from suspended reef snow dissolving in the calcium test. I’d wait a while and not use the snow and see if calcium returns to normal.

 

[nomad6]

I suspect you are getting false high readings from suspended reef snow dissolving in the calcium test. I’d wait a while and not use the snow and see if calcium returns to normal.

Thanks for your reply. I have already conducted a 25% WC and it only dropped about 3 ppm from 511 to 508 ppm. My alk also dropped under 9 but ordering new reagent as this one is about 5 mos old and it’s showing alk in the high 7s (or could the suspended reef snow be the culprit?) It had been consistent until recently after the reef snow. Weird part about it is that I had dosed it before and it didn’t spike anything. I appreciate your input thanks again

 

[Ziggy17]

So I had a similar experience this week. I dosed 7ml of DIY reef snow using 10 level tablespoons to 450ml RODI. Apparently 5ml per 50g and mine is 75 gallons water volume after deductions. 48 hours after dosing I ran my trident and got a calcium spike from 420 to 505. Alk dropped of a full DKH but mag stayed the same at 1425. So I rant the test again and got the same results. I shut down the AFR pump head to monitor. Next day, 72 hours post reef snow, calcium was at 495, mag unchanged, alk up slightly. Likely was soon after a sodium bicarbonate dose. The 10 ppm is about my normal daily calcium consumption.

Nothing changed, other than adding the reef snow.

 

[Randy Holmes-Farley Verified Community Expert]

So I had a similar experience this week. I dosed 7ml of DIY reef snow using 10 level tablespoons to 450ml RODI. Apparently 5ml per 50g and mine is 75 gallons water volume after deductions. 48 hours after dosing I ran my trident and got a calcium spike from 420 to 505. Alk dropped of a full DKH but mag stayed the same at 1425. So I rant the test again and got the same results. I shut down the AFR pump head to monitor. Next day, 72 hours post reef snow, calcium was at 495, mag unchanged, alk up slightly. Likely was soon after a sodium bicarbonate dose. The 10 ppm is about my normal daily calcium consumption.

Nothing changed, other than adding the reef snow.

The calcium reading is likely false high due to suspended particles of calcium carbonate, or a test issue. Adding calcium carbonate cannot boost calcium, and if it did somehow dissolve, it would boost alk hugely for that calcium rise.

I suppose the calcium carbonate you used may also have been contaminated with calcium chloride, or was actually calcium chloride. Did the tank turn cloudy?

 

[Ziggy17]

It was cloudy as expected for a few hours. Thing is, the test results have been high for a few days now and slowly coming down, which makes me think the tests are accurate. Especially because the tests prior to were accurate. The AFr didn’t increase the calcium either. if there was a large bolus that dosed, the mag would have spiked as well. In terms of contamination, I can’t rule it out, but I did use food grade that was recommended.

 

[Randy Holmes-Farley Verified Community Expert]

Food grade is good, but a calcium chloride contaminant would pass a food grade test.

One way to sort things out is to take some tank water in a bucket, measure alk and calcium, add a bunch of the diy snow, stir and let it settle for a few days. Then test alk and calcium.

 

[Ziggy17]

Food grade is good, but a calcium chloride contaminant would pass a food grade test.

One way to sort things out is to take some tank water in a bucket, measure alk and calcium, add a bunch of the diy snow, stir and let it settle for a few days. Then test alk and calcium.

Great idea. I’m going to do that today.

This was the calcium source used.

 

[Ziggy17]

Food grade is good, but a calcium chloride contaminant would pass a food grade test.

One way to sort things out is to take some tank water in a bucket, measure alk and calcium, add a bunch of the diy snow, stir and let it settle for a few days. Then test alk and

When it’s time to take the sample in a few days, how should I remove the sample water to ensure there isn’t particulate in the sample? Something to mimick the filtration process that would normally take place after three days.

 

[Randy Holmes-Farley Verified Community Expert]

When it’s time to take the sample in a few days, how should I remove the sample water to ensure there isn’t particulate in the sample? Something to mimick the filtration process that would normally take place after three days.

For purposes of this test, it won't matter if there is, but if you want to allow for that, take an identical sample and let it settle too for the same amount of time. .

 

[Ziggy17]

For purposes of this test, it won't matter if there is, but if you want to allow for that, take an identical sample and let it settle too for the same amount of time. .

Copy. Stay tuned.

 

[Ziggy17]

For purposes of this test, it won't matter if there is, but if you want to allow for that, take an identical sample and let it settle too for the same amount of time. .

Ok here are the comparison numbers

First sample

Alk 8.19
Cal 472
Mag 1396

Today’s sample

Alk 8.74
Cal 505
Mag 1395

This was using .025 ml into 1L of water to match the dose of 7.5 ml into my 75g tank.

Thoughts?

 

[Randy Holmes-Farley Verified Community Expert]

How are you measuring alk?

I think there may be some non carbonate calcium in that material, if the rise is real. Simple dissolution to produce 33 ppm calcium would boost alk by 4.6 dKH.

The only other possibility is some fine suspended material that dissolves in the calcium test but not the alk test. The pH is definitely low enough to dissolve it in an alk test, but if the test went very fast maybe it finished before dissolution was complete.

 

[Ziggy17]

I just used my Trident for this as it does all 3.

It’s tough using hobby grade testing and looking for spot on accuracy, but it was worth a try.
It’s somewhat consistent with what I saw in my DT, with a jump in calcium but nothing of note on alk.

 

[Ziggy17]

Hanna Alk read 7.9