Alkalinity Stability Question

[Budman's Corals]

Is it best to dose alk all day or just in the evening.
I dose 140ml a day and keep level at 171/9.5
I was dosing every 15 minutes for 24 hours a day and was curious if its any different to just dose at night for 12 hours, My level stays a constant 171 day and night , idk if this is a good thing (which im sure it is) but would it be okay to dose just at night and let the levels fall thru out the day.
Thanks for any input

 

[redfishbluefish]

Here's my belief: The more stable you can keep any and all tank parameters, the better off you'll be. By dosing small doses throughout the entire day, you're maintaining greater stability. I think you're better off. I only have the ability to set three times on my controller, and wished I could do more.

 

[Budman's Corals]

Here's my belief: The more stable you can keep any and all tank parameters, the better off you'll be. By dosing small doses throughout the entire day, you're maintaining greater stability. I think you're better off. I only have the ability to set three times on my controller, and wished I could do more.

well what about Calcium, my problem would be they will be dosing at the same time and didnt think that was a good idea

 

[redfishbluefish]

No! You don't want to dose together (only if the dosing points are far apart). How about alternating every 15 minutes, if that's possible with you controller.

 

[Randy Holmes-Farley Verified Community Expert]

Dosing alkalinity only at night could have the advantage of pushing up the pH when it was lowest, but whether to do that depends on how much it would drop during the day.

Calcium changes much more slowly (on a percentage basis) an it doesn't typically matter much how many ties a day you dose it (IMO), although in absence of any reason not to, I'd spread it out 24/7.

 

[Lonelyreef]

What if your ph doesn't change very much during the day then is it ok or better rather to split the doses up through out the day

 

[eloehr]

I am still trying to get my dosing pump dialed in, basically testing my butt off. My alk doesn't fail over night. I still dose it 6 times per 24 hours (every 4 hours)

 

[ftherrmann]

My pH and NH3 are monitored every 30 minutes. I do see a minor swing from 8.15 during the daytime and then down to 8.1 during the night. I'm dosing only during the nighttime hours (12 hours). My guess is that the pH swing would be even greater if I dosed 24 hours/day. My understanding is that more CO2 is produced during the evening hours which in turn forms carbonic acid which lowers the pH. During the day the CO2 is used and the amount of CO2/carbonic acid drops which raises the pH. Please see attached graph.

 

[Budman's Corals]

Interesting. .thanks for yalls input. My swing right now is 7.9 to 8.3 of course 7.9 is at 8am and lights come on at 10am. I know your not to worry much about ph but i think i have a big swing ,this is dosing every 15 minutes 24 hours.

 

[Randy Holmes-Farley Verified Community Expert]

What if your ph doesn't change very much during the day then is it ok or better rather to split the doses up through out the day

Then I'd spread out the doses as well as is reasonably attained.

 

[Randy Holmes-Farley Verified Community Expert]

Interesting. .thanks for yalls input. My swing right now is 7.9 to 8.3 of course 7.9 is at 8am and lights come on at 10am. I know your not to worry much about ph but i think i have a big swing ,this is dosing every 15 minutes 24 hours.

How much does the alk change in a day if you do not dose?

 

[Randy Holmes-Farley Verified Community Expert]

My pH and NH3 are monitored every 30 minutes. I do see a minor swing from 8.15 during the daytime and then down to 8.1 during the night. I'm dosing only during the nighttime hours (12 hours). My guess is that the pH swing would be even greater if I dosed 24 hours/day. My understanding is that more CO2 is produced during the evening hours which in turn forms carbonic acid which lowers the pH. During the day the CO2 is used and the amount of CO2/carbonic acid drops which raises the pH. Please see attached graph.

Yes, that all sounds reasonable.

 

[Randy Holmes-Farley Verified Community Expert]

I am still trying to get my dosing pump dialed in, basically testing my butt off. My alk doesn't fail over night. I still dose it 6 times per 24 hours (every 4 hours)

What I meant was if you only dosed at night, for example, how much would you expect alk to change when you were not dosing?

 

[ftherrmann]

Yes, that all sounds reasonable.

After 4+ years of college chemistry (most of which I've forgotten) it also makes sense to me.

 

[Budman's Corals]

How much does the alk change in a day if you do not dose?

1.2dkh it uses up per day

 

[Randy Holmes-Farley Verified Community Expert]

1.2dkh it uses up per day

So I'd probably dose 24/7.