Calcium Reactor Adjustment

[smj_115]

Hi all

This is a problem that has been bugging me for a while now. I have a calcium reactor (Deltec PF500) and a Kalkwasser mixer (Deltec K500) working.

My calcium levels have been way too low and am fighting to raise it. The best I can get the effluent at is 415ppm but with that my DKH is over 12. I cannot understand how people get a calcium level of 410ppm and a DKH of 7.5-8. I know how they are linked so if calcium level is raised alkalinity will raise also. therefore I cannot think how to raise my calcium level without having a really high DKH. Even with adding Kent Calcium every night I am struggling to raise it over 320.

I am testing using a salifert test kit and the American Marine calcium probe so that basically rules out faulty testing.

Has anybody any ideas on what i can do.

Any help/ideas would be really appreciated,

Many Thanks

Sam

[kim]

Hmmm...need more data to reply to this.

(i) The calcium and alkalinity of your tankwater.
(ii) The calcium and alkalinity of your effluent.
(ii) The magnesium levels in your tank.

But in short, if the increase in calcium generated by your reactor is "X" ppm, then it should (well, it does ! ) generate an increase in alkalinity, measured in dKH, of X*5.6/40.

So if your tank is 320, and the effluent is 415, you are adding 95 ppm calcium, and would expect to see the effluent having an alkalinity 13.3 dKH higher than your tank.

That doesn't mean that your tankwater will be pumped up to some ridiculously high alkalinity, since of course the alkalinity (plus the calcium) will be consumed. The reactor effluent is highly concentrated, and does not reflect tank conditions.

What is the alkalinity and magnesium of your tank ? It doesn't make sense that you can't raise calcium. Need to answer that first, then get things into balance, then you have a chance.

kim

[smj_115]

Hi Kim

Thanks for your reply. It doesnt make sense to me either. My Magnesium level is about 1100 so too low at the moment (I want it to be about the same as seawater if poss).

Tank
Calcium - 320
DKH - 12.80
Mg - 1100

Effluent
Calcium - 415
DKH - >16
Mg - 1195

I am using Rowalith C as the media if that helps. I have been adding Kent Marine liquid reactor Calcium on a regular basis but intend to try something different. It appears that my calcium is being consumed at a high rate although I dont have that many sps/lps and Coralline is not growing at a rate of knots - just a slow growth which suits me.

HTH

Thanks agin for your help

Sam

[kim]

Hi !

I think that you need to fix the magnesium....your alkalinity is fine and it may be simply that when you add calcium you are causing calcium carbonate to precipitate. It is magnesium that prevents this. About 1,350 ppm is the target, IIRC.

You can use a supplement from your LFS or magnesium chloride.

Happy to help, but this has been done a few times recently (magnesium is a recurring problem) so may I suggest doing a search for magnesium and after reading it up, maybe post again with any specific questions that remain

You will want to get a better handle on the dKH of the reactor effluent, but might as well fix the magnesium first.

Btw, you might ask the Mods to move this to the main "Reefs" forum. This corner of the board is a quiet spot, you'll get more responses if you fish in the main street !

kim

[GaryM]

I agree with Kim, you need to up magnesium to 1350ppm (no more than 50ppm per day) Then bring tank alk/calc into balans before using reactor. The reactor will add alk/calc in a balanced fashion so it needs to start balanced or it will always be out. The calcium levels of your effluent looks wrong, what test kit are you using, can you get a second opinion ?

[Glenn@home]

IF you are looking for levels to be close to nsw for Ca/Alk then you should be running salinity close to nsw ie 35ppt.

FWIW if you are a point or two too low with your salinty then you will see relatively large deviations in your Mg levels.

So for
34ppt salinty the 'normal' ratio of would give somewhere between 1215 -1311
and at 33 ppt 1175 - 1280ppm
assuming nsw is at 1250 - 1350 ppm Mg.

As well as checking you Mg you need to make sure that your salinity is at the right level too.

HTH
Glenn

[smj_115]

Thanks for your help guys,

I have a magnesium supplement so will slowly rise it. Then I assume I balance the Calcium using a supplement and then run the reactor. I always measure my salinity in sg, which is always between 1.024 - 1.0245 so will check that to see how close to 34/35 it is.

I did think it may be down to not having the correct balance to start with, so will get it sorted.

Your help is much appreciated.

Cheers

Sam

[Glenn@home]

typically sg 1.0265 = 35 ppt salinity so I would expect your mag to read a bit low, it does affect Ca but it appears as a smaller problem because the numbers are relatively small for Ca.

HTH

Glenn