I have a fairly new setup that is about 4 months old. It has 250 gallons of total water volume. As for calcium demand I have maybe 10-15 lps, a handful of softies, and maybe 50 or so snails of varying size. Also I have been starting to get some small corraline algae growth. I have been testing Ca and alk to see when I need to start dosing. I plan on using kalkwaser in the ato initially. The strange thing is my calcium hasn’t fallen at all but actually the opposite, it has risen. Initially I was getting reading of 460 Ca and 8-9 dkh. This is with api test. This makes sense with the fritz rpm salt I am using. About a month in my tests started consistently reading 500 Ca with the 8-9 dkh. Just tested yesterday and had 500 Ca and 8 dkh. Is this normal? I’ve considered the test kit may be bad but since the alkalinity test is steady too this leads me to believe something else may be happening. Only other thing I could think of adding calcium to the water is that I drilled my rocks for aquascaping and didn’t really clean the dust off too well. Is it possible this is adding calcium to the water? Gonna try to mix up some fresh saltwater to compare my test results with. Any other thoughts? When should I normally expect to start dosing? Am I just being impatient?
Calcium Rise Without Dosing
- Thread starter TheKyle
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glb
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I would say that’s probably test error. My Ca has never gone up on its own. API isn’t that accurate so when budget allows, I’d get a better testing kit. I use Salifert for Calcium and nitrates, Hanna Checkers for alk and phosphates. The fact that you’re getting coralline is a good sign. As far as dosing, the test results will let you know when you need to dose. Then you calculate how much you need to dose based on your water volume and the dosing directions. Measure the next week and adjust up and down depending on the results. As your corals continue to grow, you’ll need to up the dose of levels start to fall. Good luck and keep us posted!
Thanks for the help. After testing some new saltwater I think you’re right and my test kit is probably bad. Water in my mixing barrel also tested to 500 Ca. This is frustrating since the kit says it should be good til 04/2019. Guess you get what you pay for.... I’ll have to get some new higher quality test kits asap. Hope my actual readings aren’t too low. Did a 40g water change a few days ago so maybe that will play in my favor.
Randy Holmes-Farley
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Calcium won't increase on its own unless you add it somehow. I agree it is probably test error, or it is in something you are adding (or salinity is changing). 
Update - thinking the test kits were bad I had my lfs test my water. Their test had near the same results at 490 Calcium. This would seem to indicate that the problem isn’t with my test kit. Bought a new salifert test kit anyways so I can continue to compare results. I guess I can understand if my salt is mixing a little high on calcium but I don’t understand the rise in calcium in the aquarium. This was without any water changes when I first saw the rise from 460 to 500 with the api test kit. Also seems strange these levels did not drop at all in the month prior to my 40g water change. Not sure what to think but I will continue to monitor.
Randy Holmes-Farley
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You didn't rule out an inaccurate test before the "rise", or lower salinity.
That said, calcium will not keep rising on its own. It also will not go down if alkalinity is not dropping significantly.
You didn't rule out an inaccurate test before the "rise", or lower salinity.
That said, calcium will not keep rising on its own. It also will not go down if alkalinity is not dropping significantly.
This is a great point. I suppose it’s possible my calcium was on the high side from the very beginning and I don’t have enough calcium demand to see a noticeable drop yet. Being new at this I don’t really have a gauge for how long it should take before I need to start dosing. Guess I will sit back and continue to test and let the readings tell me when I need to dose. Appreciate the help.
Randy Holmes-Farley
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Use alkalinity demand as the gauge to whether anything is needed in a new tank.
You're welcome and good luck!
bluerider098
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I have been having a similar phenomenon and can't figure it out. My alk is much higher than my new saltwater. I use Tropic Marin Pro and it tests as follows.Calcium won't increase on its own unless you add it somehow. I agree it is probably test error, or it is in something you are adding (or salinity is changing).
know it's been debunked before, but all I can think is my special grade sand is buffering the water. Tank is about 9 months old.
Tank measurements
I would ignore the pH on the track measurement as my ph pen needed calibration. A more recent value is 7.8.
Since the shown measurements my KH has actually risen to 9.1 when I tested Thursday.
Can't figure it out.
bluerider098
Active Member
No just been living with it. Hasn't seemed to harm anything up to this point. Kh had been hanging around 8.8, still no dosing, only weekly waterchanges with TMP at the values shown in my previous post.
thatmanMIKEson
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What are you testing with?
bluerider098
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Hanna for both.
Randy Holmes-Farley
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I have been having a similar phenomenon and can't figure it out. My alk is much higher than my new saltwater. I use Tropic Marin Pro and it tests as follows.
know it's been debunked before, but all I can think is my special grade sand is buffering the water. Tank is about 9 months old.
Tank measurements
I would ignore the pH on the track measurement as my ph pen needed calibration. A more recent value is 7.8.
Since the shown measurements my KH has actually risen to 9.1 when I tested Thursday.
Can't figure it out.
Falling nitrate will boost alk, as can the slow dissolution of sand and rock deep down where the ph is low.
bluerider098
Active Member
Mine has finally started acting normal. It took about 1.5 years and I am not sure what was causing it, but apparently whatever it was is exhausted now. I suspect it was my substrate or my rocks, but I was never able to make any sense of it. My Alk stayed around 8.8 for the entire 1.5 years even though my fresh saltwater measured at 7.5 and I had never dosed anything.
My tank and corals finallymatured enough that my Alk started steadily dropping and I have just started dosing AFR. My ratios of Ca and Alk are right in sync with one another now.
My tank and corals finallymatured enough that my Alk started steadily dropping and I have just started dosing AFR. My ratios of Ca and Alk are right in sync with one another now.
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Are you tracking salinity? How?
Dosing anything? Using tap water?
There's not a mechanism for calcium to rise much on its own.
Ponterbuck
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I’m going through the process thing now. I’m thinking about it and I’m not a brain surgeon so I’m gonna dumb it down a lil. LoL I was thinking about it and my calcium was super stable in my 50gal for the last 5 months. I love pistol shrimp so i added a mated pair and a watchmen goby. Now since they roll sand like mad my cal has risen to 660! I’m not dosing for last two weeks and it’s gone up every test. I’m going to take a shot in the dark. I’m thinking that it’s possibly the cal that precipitated out into substrate. That’s the only explanation I can come up with since my source water tests at 405.
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Not sure what you are suggesting. Precipitation of calcium carbonate on sand lowers calcium and alk.
Dissolution of enough sand to boost calcium to 660 ppm from 400 ppm would ADD 36 dKH of alk to the water.
So the sand seems an unlikely explanation.
Test error or overdosing seem likely.
