Low calcium mystery....

[mojorizn]

So, here's a recent development ...


Did a 3 Gal WC on Saturday / checked params Sat night.

My usual params ( 65 gal display 20 sump)

Temp 78-80
DKH = 9-10
Cal = 420 - 440 ish
MG = 1470-1500
PH 8.2 -8.4

Dosing 26.4 ml of Alk daily with a pump
Dosing Cal by hand ~ 30 ml daily
MG stays @1470 - 1500 all by itself ( frequent WC's I think )

After the WC, my Cal read 380. No prob add a little right? Well Sunday AM was still @ 380.
I have added 500ml of Cal over three4 days with no increase showing ... still @ 380.

Old test kit? Nope. All tests confirmed by my LFS... Salifert / API

WTH? I have no recent changes / additions to my system other than adding Bio Pellets a week or so ago.
I have no Coraline ( tank is pretty new ) / no precipitate in the water / no excessive buildup on pumps, etc.

My brain hurts from Google / RC / NR / R2R / RA overdose ...

Ideas?

Like I said, this is outta the blue. The Cal solution I dose is fresh made last week and good.
Something is eating it up or binding it up . I'm hesitant to keep adding more Cal = sudden snowstorm...

Ya would figure 500ml over three days would show an increase...nada. Still @380. All tests done with three separate kits.

My levels have been easily maintained since the beginning and I have changed nothing except the addition pellets.

Far as I know, Bio Pellets don't absorb Calcium ... lol

- stumped -

EDIT:

I checked the solution ... it's good.
Letting DKH drop to 8

[bertoni]

What's being dosed for calcium? DIY recipe 1, recipe 2, etc? What's the alkalinity now?

[mojorizn]

BRS Two part #1.

As of today:
ALK 9 / MG 1470 / Cal 380 / PH 8.2 - 8.3

Cal has been at 380 for three days despite the additions. The Cal solution I checked using an API / Salifert kit and it was off the scale. So, I'm confident the Cal solution is good.

Have discontinued Alk dosing to let the DKH fall to 8.

[bertoni]

Okay, 500 ml of the solution should raise the calcium about 100 ppm, assuming 50g of actual water in the system, but there will be some consumption. I'd try dosing 250 ml and then measure the calcium after about 5 minutes or so.

[mojorizn]

So today, readings as follows.

DKH - 8
MG - 1470
Cal - 380
PH 8.2-8.3

Will continue to dose ALK to keep DKH @ 8.

Cal has neither risen or fallen ... no dosing.

I'd try dosing 250 ml and then measure the calcium after about 5 minutes or so.

I'll give that a shot ... thanks for ideas.

-stumped but hopeful -

[mojorizn]

So I added 350ml of Cal to the sump, checked display 15 minutes later....Cal @ 420.

Tank is 65 display + 20 sump ... btw

Will check and post tonight / tomorrow when I get home from work.