Very low Ca level effluent from reactor

euphylius · #1 10/21/2006, 12:46 PM

I refilled Ca/CO2 reactor with small crab shels media and about 10% Grotech Mg media.

I'm getting very strange results from reactor effluent:
day 1 260 mg/l Ca
day 2 140 mg/l Ca and 14 kH
day 3 60 mg/l Ca and 36 (on that day efluent is closed)

Why are readings from reactor so strange? Where is Ca going?

Thank you for your answer in advance.

Regards, E.

Randy Holmes-Farley · #2 10/21/2006, 12:55 PM

Crab shells? What kind of crabs? Unless they are hermit crabs that stole the shells from snails, those are likely not calcium carbonate and wouldn't be expected to dissolve in a reactor.

Also, something must be wrong in the testing as you should always have at least as much calcium as in the tank.

euphylius · #3 10/21/2006, 01:21 PM

Ca levels are very strange. Might be snails shels. They are spiral.

Could dissolve only Mg media and high level Mg interfere Salifert test?

carman9941 · #4 10/21/2006, 01:23 PM

are thoes reactor readings or tank readings? where you running the reactor PH?

Randy Holmes-Farley · #5 10/21/2006, 01:25 PM

I do not believe that magnesium can cause calcium readings to be unusually low.

What is the calcium level in the tank?

These may help:

A Guide to Using Calcium Reactors
http://reefkeeping.com/issues/2002-0...ture/index.htm

Calcium Reactor setup calculator (CaCO3/CO2 reactors)
http://home.comcast.net/~jdieck1/reactor.html

euphylius · #6 10/21/2006, 01:31 PM

Quote:

Originally posted by carman9941
are thoes reactor readings or tank readings? where you running the reactor PH?

Reactor readings. At this moment I don't have pH meter.

euphylius · #7 10/21/2006, 01:34 PM

Quote:

Originally posted by Randy Holmes-Farley
[B]I do not believe that magnesium can cause calcium readings to be unusually low.

What is the calcium level in the tank?

I'll ask Habib about that. As I remember he mentioned that once.

Tank level dropped from average 410 to 360 last two weeks.

Habib · #8 10/21/2006, 03:13 PM

Quote:

Originally posted by euphylius
I'll ask Habib about that. As I remember he mentioned that once.

Tank level dropped from average 410 to 360 last two weeks.

No, magnesium will not influence the calcium reading.

You might be sseing weird readings because of possible precipitation of calciumcarbonate but an increase in magnesium.

That is the Mg media is increasing magnesium but precipitating calcium.

euphylius · #9 10/21/2006, 03:51 PM

Thank you Habib. So, I might overdosed Grotech media

jdieck · #10 10/27/2006, 02:52 AM

Where did you get the shells? Are they supposed to be used in reactors?
Usually shells are formed of Calcite not Aragonite which may require a lower PH to dissolve than Aragonite. Knowing your reactor's PH might help.
Have you tought of switching the shells to an Aragonite or Crushed coral media?

euphylius · #11 10/27/2006, 07:31 AM

Shells are from part of the coast, where there are tons of them in small area. But they are fare from you

These crushed shells I'm also using as part of the plenum.

You might be right. Low ph maybe caused Mg media to dissolve quickly. My friend uses these shells without MG media and he is having 460 Ca without problem in display.

I had to react quickly because of low Ca, so I unfortunately didn't measure ph. Now I have crushed corals in reactor.

jdieck · #12 10/27/2006, 11:10 AM

Glad to hear things are improving.