I have no clue what I'm doing...

[CastAway]

Randy - I have a 150g display, 210g total volume, filter socks, skimmer, refugium full of caulpera, about 10 tlbs GFO in a reactor and a Ca reactor (ARM, 50ml effluent output at 6.4pH) - a few zoas, LPS and a couple SPS, ten small fish. Tank running just over six months.
Current params:
Sg - 1.026
pH - 8.2 - 8.3
dKH - 12.6
Ca - 410
Mg - 1260
NO3 - 0
PO4 - 0

I made a huge mistake with GAC, started a 16oz bag in my sump, then a week later another, and a week later another. I had no idea it was too much. I think the GAC was behind the loss of three birds nests. I've removed two bags now, and am just running one.

My montipora has lost all it's color. I don't want to loose it. Everything else looks fine, to me.

If it's true that all that carbon shocked my system, could removing 2/3 of it now do the same?
How do I get my params in order? All my Ca reactor seems to do is drive my alk up, while Ca and Mg just stay low.

I could really use a kindergarten level education on alk and GAC

anda:

 

[Randy Holmes-Farley]

I don't know if the GAC shocked it, but it might have if it was very yellowed before it and then suddenly a lot more UV light was getting to the corals.

In any case, removing it now won't produce another shock, but might not help much either if this is what happened.

The coral problem was sudden with this use of the GAC?

 

[CastAway]

The coral problem was sudden with this use of the GAC?

It took a little over a week for the three birds nests to die. The water was clear when I started the GAC, and I have just one LED fixture over the tank. I suppose it could have been increased light intensity. Not sure. I was also slowly increasing the output of my Ca reactor at the time, and first suspected it may have been an alk swing that killed them. But, a friend in my club told me that a transition from 10 to 13 on alk, over the course of three weeks, was not problematic.

Corals are gone now, and if removing the GAC is not an issue, does one usually have to does Ca and/or Mg while using a CA reactor? Will adding Ca or Mg decrease my alk?

 

[Randy Holmes-Farley]

Corals are gone now, and if removing the GAC is not an issue, does one usually have to does Ca and/or Mg while using a CA reactor? Will adding Ca or Mg decrease my alk?

Not unless you add so much calcium you force precipitation of calcium carbonate, which I wouldn't do.

Dial back the reactor CO2 addition rate (raise the pH, if that is how you control it) to allow alkalinity to decline. At 13 dKH, I might even turn off the CO2 cylinder for a while.

 

[CastAway]

Not unless you add so much calcium you force precipitation of calcium carbonate, which I wouldn't do.

Dial back the reactor CO2 addition rate (raise the pH, if that is how you control it) to allow alkalinity to decline. At 13 dKH, I might even turn off the CO2 cylinder for a while.

Dialed it back. Thanks. They should call it an alkalinity reactor, not a Calcium reactor.

 

[Randy Holmes-Farley]

:lol: Good point.

FWIW, I never call it a calcium reactor.

 

[CastAway]

Ca, dKH and Mg are such a common theme on this forum.
So confusing. Seemingly no kindergarten understanding possible.
My alk is high, and my Ca and Mg are low.
Which do I try to address first? Ca first, in order to lower pH? Mg first, as a buffer?

UGH!

 

[Randy Holmes-Farley]

What are the current values?

 

[gcrawford]

Slow drip from the cal rx, ATO runs through my kalk rx, I change things as little as possible. Stability, stability, stability. I find that the less I fiddle with it, the better everything thrives which is good for peace of mind when I travel. This method works for me and - I enjoy the hobby much more - not stressing about perfection. My apex takes care of everything for me and sends me a message if anything needs attention.

Again, that works for me, not telling anyone how to be. If I want to experiment, I set up a small tank and try new things. To much invested in my big tanks to chase numbers.

G

 

[CastAway]

So, if presently I am introducing 10ml per minute of 6.4pH effluent, and I reduce the CO² so as to introduce 10ml of 7.0 effluent per minute, this will help to lower my alk?

Current parameters are:
dKH – 11.6
Ca – 410
Mg - 1240

I think I'm only just now catching up to your "turn the CO2 off" comment.

 

[Randy Holmes-Farley]

Any reduction in CO2./raising of the pH in the reactor will add less alkalinity.

If you are adding less than the demand, it will fall.

The other two are fine, but you could boost them if you wanted to. I'd do it with calcium chloride and magnesium chloride/sulfate. You can do either one at any time.

 

[CastAway]

You know, as a newbie, I am trying to learn. Often, not just to learn something new but to remember something I’ve forgotten, or perhaps mis-prioritized.

I remember now, as I was researching Ca reactors and first decided to employ one in my system, having at least a better grasp on this topic.

This has been kind of an “ah-ha” moment, a Homer Simpson “doh” moment.

My alk has dropped to less than 10 now. I simply changed the set point on my pH controller. I hope to find an actual equilibrium now, between effluent output rate, effluent pH and my system alk demand. At least I hope I'm on y way to that.

Thanks

 

[Randy Holmes-Farley]

I think you are on your way.

Good Luck and Happy Reefing.