ATTN: Aarone, Gypsum update.

cprdnick

Active Member
Hey bud, I have a question that maybe your wonderful sister could answer for me. Do you remember me talking about the Calcium Carbonate sand? Well, with the help of your sister we figured out that the calcium would precipitate first, and it did, my Ca readings are now 1200+.
The main thing I want to know is why is the sand turning black towards the bottom of the sand bed? Right now it's just a small 4 inch long patch and it's not totally black but it's getting there. It also appears to be reaching further towards the surface.
I appreciate your help.
 

aarone

Active Member
I will ask about the color but i have my own thoughts about it.
Have you ever had a DSB? Gray or darker areas are anoxic zones where the actual denitrifying occurs. Now if your calcium levels are at 1200+ is there any excess precipitation that is noticeable?
 

bang guy

Moderator
1200 sounds a bit unreasonable unless your PH is really really low. I think something's wrong with your test kit.
 

cprdnick

Active Member
My pH is sitting at around 7.4, this tank is still cycling so I haven't bothered to touch the pH. It did have some noticeable precipitation for a day or so a while back, but now everything is crystal clear.
Well, I'm not sure at what point calcium starts to precipitate visually, but I've been experimenting with Calcium Sulfate sand to see if it would work, and Aarone said that the calcium would definately precipitate. I haven't had any true problems with this test kit as of yet.
 

bang guy

Moderator
ahhh now I understand... 7.4 is low enough to handle that kind of Calcium but I'm surprised the Gypsum is dissolving. I would have though the PH would have to be below 7.0 to dissolve the Gypsum.
Lots to learn.. lots to learn.
Thank you for sharing.
 

cprdnick

Active Member
Do a search on my name and the word gypsum, I didnt explain it real well, but it gives you a general idea of what I'm up against in the original thread.
 

aarone

Active Member
clint,
i would have asked my sister if it was normal for the substrate to trn black....but she came home today with possible appendicidis (sp?)
I will ask when she gets better.
aaron
 

cprdnick

Active Member
Nah, she can answer a question in pain, lol. Ok, it's not a problem, I hope she starts feeling better. Give her my best.
BTW, no I haven't ever had a DSB, so I suppose that is what is happening. I checked my ammonia today and it hit 0 and my trites are at .25. So I'll bet that the sand is maturing or something. I was just worried that some kind of chemical reaction was taking place. Of course this is experimental so I guess I can't get too worried. I'm hoping maybe the Ca will drop as the tank ages, or after some water changes.
Thanks a bunch
Clint
 

aarone

Active Member
Is the gypsum actually dissolving or staying relativly intact?
also How does the SG look?
 

cprdnick

Active Member
The gypsum has not dissolved as far as I can tell, of course it may take a few weeks more to tell a difference in bed depth. My SG is stable as long as I stay with the top offs. So far other than the high Ca, I haven't noticed any parameters that worry me yet.
 

aarone

Active Member
well this sounds like a great experiment....maybe you should try mixing an equal amount of gypsum and aragonite in the future???:thinking:
 

cprdnick

Active Member
I will, but the main reason I wanted to try the gypsum was because I'm broke and I have a bunch of this gypsum stuff.
 

aarone

Active Member

Originally posted by cprdnick
I will, but the main reason I wanted to try the gypsum was because I'm broke and I have a bunch of this gypsum stuff.

lol trust me i understand completely!
 
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