Help excessive alkalinity demand

[ncfishguy]

My magnesium is at 1350,my calcium is at 430, my alkalinity drops down to 6 daily. I use reef crystal salt

 

[HB AL]

What does it drop from?
Assuming everythings in order then up the dose.

 

[TheEngineer]

Alk and calc are used together. Odds are you either are having a testing error or the alk is precipitating out. How are you adding alk and how are you testing?

 

[ncfishguy]

8

 

[ncfishguy]

I noticed when I dosed alk was like little flakes like snowflakes

 

[ncfishguy]

What does it drop from?
Assuming everythings in order then up the dose.

Everything was perfect like a month ago and then all of a suddenly it started using all and nothing else

 

[HB AL]

Thats a decent size drop, is the tank loaded with corals? Is the salinity the same when you do each test also water temp?

 

[ncfishguy]

Alk and calc are used together. Odds are you either are having a testing error or the alk is precipitating out. How are you adding alk and how are you testing?

Are you salifer test kits and I added manually with a little cup measuring cup

 

[ncfishguy]

Thats a decent size drop, is the tank loaded with corals? Is the salinity the same when you do each test also water temp?

Yes and it is loaded with coral

 

[Randy Holmes-Farley Verified Community Expert]

I noticed when I dosed alk was like little flakes like snowflakes

That’s normal, assuming it redissolves are it is stirred in.

 

[Randy Holmes-Farley Verified Community Expert]

Yes and it is loaded with coral

2 dKH day is not unusual in a reef tank like yours. Even a soft coral tank can use that if coralline is growing well.

 

[Randy Holmes-Farley Verified Community Expert]

Everything was perfect like a month ago and then all of a suddenly it started using all and nothing else

I’m certain it is using calcium and magnesium too (unless the alk consumption is from a sulfur denitrator), but those deplete more slowly and are harder to see over the short term.

 

[ncfishguy]

I’m certain it is using calcium and magnesium too (unless the alk consumption is from a sulfur denitrator), but those deplete more slowly and are harder to see over the short term.

Yea calcium is goin from 450 to 430 daily but alk is 8 down to 6 daily

 

[Randy Holmes-Farley Verified Community Expert]

Yea calcium is goin from 450 to 430 daily but alk is 8 down to 6 daily

Which is approximately balanced demand. It's actually a tad more calcium deamand than exactly balanced, but I'm sure the difference is testing/rounding errors.

It just looks like so much more alkalinity, but true balanced demand in a typical reef tank is about 18-20 ppm of calcium for each 2.8 dKH of alkalinity.

The reason calcium demand is a range is that there are variable amount of magnesium (and to a much smaller extent, strontium) in the calcium carbonate in place of calcium, depending on which organisms are depositing it and the actual relative concentrations of Ca/Mg/Sr in the water.

 

[ncfishguy]

Which is approximately balanced demand. It's actually a tad more calcium deamand than exactly balanced, but I'm sure the difference is testing/rounding errors.

It just looks like so much more alkalinity, but true balanced demand in a typical reef tank is about 18-20 ppm of calcium for each 2.8 dKH of alkalinity.

The reason calcium demand is a range is that there are variable amount of magnesium (and to a much smaller extent, strontium) in the calcium carbonate in place of calcium, depending on which organisms are depositing it and the actual relative concentrations of Ca/Mg/Sr in the water.

Awesome thanks [emoji5]

 

[ncfishguy]

I just need to get on a dosing schedule then

 

[Randy Holmes-Farley Verified Community Expert]

I just need to get on a dosing schedule then

Yes, that seems appropriate.

 

[CurtnStac]

I just need to get on a dosing schedule then

What size is your tank? I have an 80g, mostly euphyllias and softies. Currently I have to dose a little alk twice a week but a 10% water change with reef crystals keeps cal and mag in line.