Calcification Rates Day vs. Night

[steamguy]

Hey Everyone,

I have been running a calcium reactor on my tank for the last three years or so. About four months ago I upgraded to the Masterflex-Carbon Doser setup that is so popular here and couldn't be happier. I am currently running a CP 7523-80 at 9 ml/min. My tank is only 65 gallons and has fairly low demand. I tend to add things very slowly, but my focus is SPS.

I have always enjoyed reading the calcium reactor vs. doser debates. In one of these debates I remember someone mentioning that they preferred to run a doser because they were able to get more stable ALK throughout the day and night. They made the argument that corals calcify much more during the day so calcium and alkalinity demand is higher. But at night as calcification slows down calcium and alkalinity tend to rise, as there is less demand for it.

Does anyone test at night, or right before the lights go on to see if they get any appreciable rise in alkalinity? I assume if there were a rise it would most likely be pretty small and wouldn't affect the corals too much.

I also run an apex, I have a pH probe in my calcium reactor controlling CO2, and one monitoring the tank as well. It would be easy to set up two virtual outlets to control the calcium reactor pH. One would control daytime (lights on) and run the reactor at a lower pH, and another virtual outlet would run nighttime (lights off) at a higher pH. My question is, is it worth it? And is that a safe way to run the tank and reactor?

I'd love to hear some opinions.

Thanks

James

 

[Piper27]

I thought growth happens at night? Could be wrong. Also I would not think there would be much of difference day or night when testing alk. Definatly haven't heard of anyone saying dosers are better because they can control that difference. I have tested at night before and during the day and I dont remember any difference no matter if I had my reactor or doser running. Who knows maybe someone can give a different answer.
But running your calcium reactor with two different settings and probes may be more risk of something going wrong for a minimal effect on your system.
Only thing I have tried to stabalize from night and day is ph and I dont even worry about that anymore as long as it's not a huge swing.

 

[swk]

My alk is always higher first thing before the lights come on. I too run a calrx with peri feed pump. I suspect this is due to a couple factors.

1 - the ph of the tank water that is feeding the reactor is lower, making the ph in the reactor slightly lower resulting in a more potent effluent

2 - different rates of use during night vs day by the corals.

All in all, it's a small difference but it does happen. Because of this, I always test alk, which I do DAILY, between 7-8pm so I can truly tell what is going on.

 

[Piper27]

I read a little bit of stuff and seemed to get that sps grow during the day and night, but more during the day. And there were a few discussions on this topic too. I would like to hear from anyone with more info on this stuff.

 

[spsfreak25]

I have read and seen multiple articles stating that hard coral do most of the growing at night and during the day is when they use the light to photosynthesis and break down the sugars they need and absorb the alk, calcium, and other trace elements. After doing that all day long they use what they have absorbed and they start to build the skeleton structure.

 

[Piper27]

I have read and seen multiple articles stating that hard coral do most of the growing at night and during the day is when they use the light to photosynthesis and break down the sugars they need and absorb the alk, calcium, and other trace elements. After doing that all day long they use what they have absorbed and they start to build the skeleton structure.

This is what I had thought before. The articles I just read were not specific to sps.
When using a doser I always have dosed at night because of this as well as keeping ph up. When running a reactor I haven't worried about either.

 

[spsfreak25]

This is what I had thought before. The articles I just read were not specific to sps.
When using a doser I always have dosed at night because of this as well as keeping ph up. When running a reactor I haven't worried about either.

I never dose at night as my fudge light is plenty strong enough to keep the ph up. Also if you dose alk at night it can drop your ph even lower. Calcium is dosed a few hours after the alk is done dosing so it does not start to participate in the water. So basically my calcium starts dosing around 8ish and goes all the way to I believe 1 or 2am.

 

[C.Eymann]

I agree with Piper, I remember reading in Alf Jacob Nielsen and fossa's modern reefkeeping series that calcification took place predominantly at night, but recent studies have shown that the higher O2 levels around the calcifying tissue that are experienced during the photoperiod vs night/respiration lead to more rapid calcification.

 

[Geeray]

I never dose at night as my fudge light is plenty strong enough to keep the ph up. Also if you dose alk at night it can drop your ph even lower. Calcium is dosed a few hours after the alk is done dosing so it does not start to participate in the water. So basically my calcium starts dosing around 8ish and goes all the way to I believe 1 or 2am.

Am I missing something? How would dosing Alk lower ph? Dosing Alk would raise ph if anything.

 

[Piper27]

I was wondering the same thing.

 

[C.Eymann]

If he/she is using recipe 2- using unbaked baking soda, it can lower pH slightly.