Ca/Kh usage

Jguido1987 · Nov 2, 2017

I was hoping someone would know if this “sounds” right. I have been really tracking my parameters for calcium and alk over the past 2 weeks. In an attempt to get to check my daily usage/amount to dose. I do not own an automatic doser. I am using Kent’s A/B product. I am thinking of switching suggestions are appreciated. But right now I am using about 10ml of B for alk a day. And 30ml of A for calcium a day. My Tank is only about 25 gal of water volume. I guess a 1:3 ratio doesn’t seem that high writing it out now. But still seems like a lot of calcium for a small Tank.

Gareth elliott · Nov 2, 2017

Jguido1987 said:
I was hoping someone would know if this “sounds” right. I have been really tracking my parameters for calcium and alk over the past 2 weeks. In an attempt to get to check my daily usage/amount to dose. I do not own an automatic doser. I am using Kent’s A/B product. I am thinking of switching suggestions are appreciated. But right now I am using about 10ml of B for alk a day. And 30ml of A for calcium a day. My Tank is only about 25 gal of water volume. I guess a 1:3 ratio doesn’t seem that high writing it out now. But still seems like a lot of calcium for a small Tank.

Calcium and alkalinity should be dosed in equal parts. Your water has a particular carrying capacity and both are battling for the same space. Try reducing to 15ml each for a week testing each day. Your aim is stability not perfect numbers. At the end of the week tweak up or down in small numbers and repeat till your alk/ca are stable within an acceptable range.
Your corals will be happier at around 390 calcium everyday than 450 on Monday, 420 on Tuesday, etc.

Jguido1987 · Nov 2, 2017

That’s where I get confused. My ca ppm goes down by 20pts per day if I don’t dose anything. And my alk drops about 1 dkh per day with no dosing. I know that adding 10ml of part B will keep my alk the same from morning to morning. But in order to keep my Ca levels stable and to raise it the 20pts that is consumed over the course of the day it requires 30ml of part A. That keeps my levels at 9dkh and 440ppm. I usually add the 10ml in the morning of part B and can either add half of part A in the morning and the other half in the afternoon.
My question would be if I add an equal part like you suggested of 15ml each per day wouldn’t my consumption rate of the calcium continue to drop below desired levels, obviously slower at lets say 10pts less each day. And wouldn’t my alk levels continue to rise by 0.5dkh per day? I know mag plays a big part in this and I keep that around 1350ppm.

Randy Holmes-Farley · Nov 2, 2017

Instead of telling us volumes, can you give us the alk and calcium consumed per day?

The balanced consumption ratio is about 1 meq/L (2.8 dKH) of alk per 18-20 ppm calcium.
You aren't actually consuming three times that amount of calcium, but water changes might be messing with the real ratio.

Jguido1987 · Nov 2, 2017

I think my daily consumption is around 20ppm of calcium and 1 dKH per day right now. My test kits are the API kits so it’s hard to get an exact amount. But I have been getting consistent readings.

Jguido1987 · Nov 2, 2017

I am due for my weekly waterchange. But held off a day or two to try to get a better consumption reading.

Randy Holmes-Farley · Nov 2, 2017

That ratio, if accurate, is not from in tank consumption, unless nitrate has accumulated quite a bit during that period. Most likely, there is some testing issue.

Jguido1987 · Nov 2, 2017

Now I’m even more confused. Hahaha
If that ratio is not based on Tank consumption, then what/where is the Ca/Alk going? Because if I don’t add any chemicals (A/B) my alk rating drops by 1dKH and my calcium drops by 20ppm. I do expect the corals to be consuming the “elements” so I’m not concerned about that. But if I understand what youre saying is that the ratio of consumption is off. What should I do? What can be done?

Randy Holmes-Farley · Nov 2, 2017

Jguido1987 said:
Now I’m even more confused. Hahaha
If that ratio is not based on Tank consumption, then what/where is the Ca/Alk going? Because if I don’t add any chemicals (A/B) my alk rating drops by 1dKH and my calcium drops by 20ppm. I do expect the corals to be consuming the “elements” so I’m not concerned about that. But if I understand what youre saying is that the ratio of consumption is off. What should I do? What can be done?

Don't do anything except maintain them. It is not a problem, it just isn't likely highly accurate.

It is most likely test error if not due to water changes or salinity changes messing with ratios. Calcium changes pretty slowly, and has substantial test to test variation.