calcium and alkalimity

[eholceker]

Lately I have been having some huge issues trying to raise my alk and cal. No matter how much buffer or Calcium I add I cant get higher than 400 calcium 8 DKH. I am trying to get to 425-450 on the calcium and 10-11 DKH. My magnesium is at 1250. I do have a bunch of sps and LPS corals but never had issues before. Any idead on what I could do?

 

[Phyl]

Do you have glass tops on your tank? Otherwise covered? Tight canopy? You may be suffering from supressed Co2. That would suppress the alk. Try getting your mag closer to 1350, which might help allow the Ca to come up a bit, and add a fan over your sump or tank to remove the Co2 sitting over the tanks water surface.

 

[eholceker]

Phyl,
The whole tank is open. I will try to get the mag up but I also wonder if the dsb can cause higher CO2 levels? I do have alot of surface movement though a long with a fan in my sump. I'll try to raise the mag a bit and see if that helps at all.

 

[Phyl]

How big is your system and how much alk addative (and what kind) are you adding at a time? How's your PH?

 

[eholceker]

Phyl,
The full system is 75 gallons. I add 3 capfuls of kent super buffer and 1 1/2 capefuls of liquid calcium. Before this I was using seachem products but once they stopped working I though I would change buffers. Last time I checked the PH it was 8.1 in the morning 8.3 at night.

 

[kheflw]

A DSB will cause a drain on Alk & Ca. Not sure if it has anything to do with CO2, but I've heard that Bare Bottom Tanks use less Alk & Ca.

I'd say you simply are not adding enough of the additives.

Is there a reason that you want 10-11 DKH? I run my tank at between 6 - 7 DKH. I keep my Ca at around 400. I use a lot of Additives to acheive this.

 

[Brian]

Last time I checked the PH it was 8.1 in the morning 8.3 at night.

Forgive me if I'm wrong, but doesn't PH usually drop during the day and then rise during the night? Are you sure your readings are accurate?

 

[RichT]

Unless you have your fuge lights on opposite of the display, your PH will drop overnight and be at it's lowest first thing in the morning. When the lights are out and there is nothing to photosynthesize, the animals aspire using the O2 in the water and expelling CO2. The effects of the additional CO2 cause the PH to drop.