Calcium doing things it shouldnt

[Randy Holmes-Farley]

Randy is that due to low pH or what would cause the sand and rock to dissolve???? Just curious and I didn’t know it could happen in reef tank….

Various processes lower the pH inside rock pores and down in sand. Conversion of ammonia to nitrate, and degradation of organics to CO2 will both do it.

 

[Randy Holmes-Farley]

Very interesting. I wonder if it has to do with my choice of crushed coral as substrate. This is my first tank I've used it on. I will say that this particular track also struggles with low pH. I have 3 other tanks in the house that all sit about 8.1-8.2, but this tank struggles to reach 7.8 at its highest during the day.

Crushed coral may allow more penetration of organic detritus down into the sand.

Cleaning it more often may help.

 

[Pod_01]

Various processes lower the pH inside rock pores and down in sand. Conversion of ammonia to nitrate, and degradation of organics to CO2 will both do it.

Randy as this happens would it not raise Alk as well? To me it sounds like calcium reactor!!!
Or is the Alk increase minimal and consumed as it is created.

 

[SaltwaterandLime]

Randy as this happens would it not raise Alk as well? To me it sounds like calcium reactor!!!
Or is the Alk increase minimal and consumed as it is created.

In my tank calcium was more noticeable at first, both both alk and calcium are being raised at a fairly steady rate each week

 

[Randy Holmes-Farley]

FWIW, I don’t think most common reefing materials will add alk and not calcium or calcium and not alk. Both typically are added in the proportion of 20 ppm calcium to 2.8 dKH of alk, but what you notice first is usually alk.

 

[SaltwaterandLime]

FWIW, I don’t think most common reefing materials will add alk and not calcium or calcium and not alk. Both typically are added in the proportion of 20 ppm calcium to 2.8 dKH of alk, but what you notice first is usually alk.

The longer this phenomenon continues in my system, the more convinced I am that it is not a result of any product or combination of products.

I really do think your suggestion of some sort of dissolution of rock/sand is to blame.

I used caribsea arag-alive for the substrate, and enough other reefers use this without the same issue so I don't think it's the sand. I can't see even my lower tank pH of 7.6-7.8 causing that without other people seeing the same results. I'm going to assume it's my rock. I admit to talking a chance on some cheap rock offered locally and I have no way of knowing what it's actual original source is.

Twice a month ICP tests have shown no other concerning elements showing up so at this point my plan is to just do nothing and hope eventually my corals outgrow the issue.

I really would like to find a way to get the pH up in this tank, it seems odd that it stays so much lower than my other systems do when I maintain them all fairly consistently.

Right now I see a weekly increase of just about 1dKH and 30ppm calcium. I bring it down on Sundays with a water change using lower parameter salt, and it gradually rises back up over the week.

 

[Randy Holmes-Farley]

Randy as this happens would it not raise Alk as well? To me it sounds like calcium reactor!!!
Or is the Alk increase minimal and consumed as it is created.

Yes, it's exactly like a reactor.

 

[SaltwaterandLime]

Interesting recent development in my tanks saga;

After noticing the pH in my tank beginning to drop concerningly low at night (7.6-7.7) I decided to try dosing a small amount of diluted kalkwasser during lights out just to try and help stabilize the pH swing.

I'm still never going any higher than 7.9, but my low isn't AS low in the mornings now.

Since hooking up the doser to add kalkwasser to my tank, my calcium and alkalinity have stopped rising and stayed almost perfectly stable for the first time in months.

Not sure if any of that has any connection but it's interesting

At the same time, since starting kalkwasser, the ORP in my tank has almost doubled. I've neve paid much attention to that probe other than the fact that it's just there because it came with my Apex, but I thought it was interesting that it's always stayed in the 200's and now suddenly it's reading in the 400's

 

[Pod_01]

Interesting recent development in my tanks saga;

After noticing the pH in my tank beginning to drop concerningly low at night (7.6-7.7) I decided to try dosing a small amount of diluted kalkwasser during lights out just to try and help stabilize the pH swing.

I'm still never going any higher than 7.9, but my low isn't AS low in the mornings now.

Since hooking up the doser to add kalkwasser to my tank, my calcium and alkalinity have stopped rising and stayed almost perfectly stable for the first time in months.

Not sure if any of that has any connection but it's interesting

At the same time, since starting kalkwasser, the ORP in my tank has almost doubled. I've neve paid much attention to that probe other than the fact that it's just there because it came with my Apex, but I thought it was interesting that it's always stayed in the 200's and now suddenly it's reading in the 400's

That is good news, not sure how that works though. Kalkwasser adds both Alk and Calcium and the side benefit is increased pH.

My experience with ORP is that you need to clean it every so often, as things start to grow on the sensor the reading changes suddenly and I know it is time to clean all the probes, including pH probe. Usually after cleaning all the readings are back to normal. I am really not sure what ORP is good for.

Good to know the tank is now behaving as most reef tank bahave with Alk and Ca.