Calcium help

bhavy · Jan 16, 2018

So I checked my calcium this morning right before my Doser started dosing 270ml for the day. Calcium was 381. At 7:30 pm after about 250ml had been dosed I re-checked my calcium and its 353! What! Where dos it go? I've been steadily raising my calcium to try and get it above 420 the last few months. It is acting as if it is precipitating but I don't see it doing so? Help would be appreciated! 200 gallon tank 10 corals total

Martin Kuhn · Jan 16, 2018

Sounds like a measurement error

Randy Holmes-Farley · Jan 17, 2018

I agree. It didn't likely decline that much that fast, even with no dosing. If somehow you consumed that much (with no actual dosing), alk would need to decline by 4 dKH. In reality, it would be even more since you dosed some amount of calcium. I assume that didn't happen.

bhavy · Jan 17, 2018

Just to clarify... I did dos 250ml over that time period and it was lower after the dosing? Do you still think it was a measurement error? I use the Hanna..
Thanks

Randy Holmes-Farley · Jan 17, 2018

bhavy said:
Just to clarify... I did dos 250ml over that time period and it was lower after the dosing? Do you still think it was a measurement error? I use the Hanna..
Thanks

Yes, that was my point. It is even more likely to be error if you actually dosed any calcium. It can't have dropped as much as you measured, and testing is not as accurate as most would like.

bhavy · Jan 19, 2018

Ok, I'm going crazy with this so I borrowed another test kit and am going to test tonight. Since last comment I upped my Doser to 300ml each of 2part. Late in the day (same time I always test 7pm) my calcium was 353 , Alk was 7.7. (My Alk doses from 11:00pm -9:00AM)
The next morning I retested Alk and it was 8.6. So it went up 1.1 Dkh with 300ml added. Going to test for calcium with my kit and my borrowed kit at 7:00pm tonight.
I will post results....
Thanks
The next morning

bhavy · Jan 19, 2018

Ok...results are in. I borrowed a second test kit.
I have 2 Hanna checkers. I tested for calcium 352 and 355. So I can eliminate a tester error/variance. Actually that's pretty impressive . I also tested the reagent from each test kit against each other....same results.
Then I tested newly batches saltwater (Red Sea Coral Pro) had mixed for 3 days. Calcium -440!
Ok , so now I'm thinking I'm precipitating somehow even though I see no evidence of such. So i feel I'm getting somewhere.
I do a 20% water change. I let the system run for 1 hour. I retest for calcium......ready for this?
Calcium 352!
Anyone have a explanation or theory?! About to stop dosing altogether...
Thanks

Randy Holmes-Farley · Jan 19, 2018

FWIW, the new test confirms the current value only. A test error in the original value is still a viable explanation.

You would not expect very much rise from a 20% water change. Only from 355 to 372 ppm.

If you want to boost calcium, make a one time correction to just the calcium without dosing alkalinity. Have you been adding both calcium and alkalinity, or just calcium?

Randy Holmes-Farley · Jan 19, 2018

What actual product are you using for calcium? Did you use a calculator to set the doses for the boosts?

bhavy · Jan 19, 2018

Randy, I'm using your receipe 2 cups Soda Ash (BRS) to one gal ro water.
I have been 1 to 1 dosing 250ml each

bhavy · Jan 19, 2018

Should I add about 800ml to boost then, wait a few days and repeat? That would take me to about 440ish. But my ALK would fall . Or should I stop dosing and just do a few water changes over then next month?
Thanks for the help

bhavy · Jan 31, 2018

Anyone think a ALk swing of 1.0 Dkh (7.0 in evening 8.0 in Am ) is a problem or am I OCD?

Randy Holmes-Farley · Jan 31, 2018

bhavy said:
Anyone think a ALk swing of 1.0 Dkh (7.0 in evening 8.0 in Am ) is a problem or am I OCD?

Depends on the tank type. For SPS, smaller changes may be better.

How are the parameters now?

bhavy · Feb 3, 2018

Calcium around 410
Alk 7.5-8.2. That's dosing 160ml of each. Going to run with that for another week before maybe increasing. I'm starting to wonder if I should dose at the beginning of the sump instead of the return chamber..

Mr.Fishtank · Feb 3, 2018

Need to test mag. If it's too low, you will never be able to get your alk and cal where you want them.

Randy Holmes-Farley · Feb 3, 2018

bhavy said:
Anyone think a ALk swing of 1.0 Dkh (7.0 in evening 8.0 in Am ) is a problem or am I OCD?

I might split the dose into an AM and a PM dose to reduce the daily swing.

Randy Holmes-Farley · Feb 3, 2018

bhavy said:
Calcium around 410
Alk 7.5-8.2. That's dosing 160ml of each. Going to run with that for another week before maybe increasing. I'm starting to wonder if I should dose at the beginning of the sump instead of the return chamber..

Those values certainly seem fine. Dosing into the highest mixing area is best.