Why doesn’t my calcium drop?

[Randy Holmes-Farley Verified Community Expert]

Totally on this subject in a 20 gallon, about 60 kryptonite candy cane heads, a few montis growing crazy, a few ricordea and a 30+ head and growing acan colony. My dKH sits around 9.5 on hanna checker and calcium at approx 450 red sea pro, mag 1350 average on salifert. Tank setup 7/2017 and rocks are 30lbs figi I've been running since 2011.

My wife got me a galaxea tooth coral, a couple favias, 3 monti frags and a few zoas for Christmas and with in a week my alk dropped to 6.5 dKH. Calcium is within average range.

I'm using B-IONIC 2 part, and for the last couple years 6 drops a week of each keep the 9.5 dKH and calcium within range.

The directions say add 1/ml per 4 gallons but do not say what the increase would result. I moved to 10 drops a week and I'm at 6.8-7.1 dKH.

Question is, approx how much part 1 needed to get back to 9.5?

This calculator can be used to answer such questions:

Reef Chemistry Calculator

 

[Randy Holmes-Farley Verified Community Expert]

Don’t mean to hijack but a search lead me here.
I have a 130 gallon tank mainly sps dominant

i hve about 6 med-large acro colonies and lots of smaller colonies and frags. im dosing 60ml of brs 2 part. I had a nutrient issue where it bottomed out and tank almost crashed. All corals have revived nothing died. Growth has been stagnant, but getting better. Encrusting portions of acros are growing fast but not many new branches.
Started doing awc 30 gallons a week, feeding heavy, and now my alk is still being consumed at 60ml per day but I have completely stopped dosing calc. Im confused....

There are some processes that use alk only (such as ammonia conversion to nitrate), but corals cannot do so.

I expect it is a matter of the salt mix maybe having excess calcium, and not watching long enough to see the calcium decline, which is always much slower on a percentage basis.

This has more:

http://reefkeeping.com/issues/2004-12/rhf/index.htm

 

[onetootreefor]

There are some processes that use alk only (such as ammonia conversion to nitrate), but corals cannot do so.

I expect it is a matter of the salt mix maybe having excess calcium, and not watching long enough to see the calcium decline, which is always much slower on a percentage basis.

This has more:

http://reefkeeping.com/issues/2004-12/rhf/index.htm

thanks randy! Im using tropic marin pro, it is only rated for around 440 calcium, which is right near where mine stays without dosing. I was just confused as I have never had a tank where I was using so much more alk than calcium.

 

[Randy Holmes-Farley Verified Community Expert]

thanks randy! Im using tropic marin pro, it is only rated for around 440 calcium, which is right near where mine stays without dosing. I was just confused as I have never had a tank where I was using so much more alk than calcium.

How much alk (in dKH per day)?

 

[onetootreefor]

How much alk (in dKH per day)?

Honestly im not sure I don’t know how to do the calculation. I just bumped up my dose to 65ml per day using the brs sodium bicarbonate pharma pouches on ~130 gallon system

 

[Randy Holmes-Farley Verified Community Expert]

That is quite a low dose (about 0.32 dKH per day) so the expected calcium decline, even if all the alk is going into calcium carbonate, is only about 2 ppm per day. It may take quite a while to reliably detect that decline.

 

[onetootreefor]

That is quite a low dose (about 0.32 dKH per day) so the expected calcium decline, even if all the alk is going into calcium carbonate, is only about 2 ppm per day. It may take quite a while to reliably detect that decline.

Ok excellent thank you for the confirmation Randy. Didn’t realize how little my alk dose was contributing. Im used to my 30 gallon 65-70 would be a lot more in dKH