Calculate alkalinity demand using Calcium reactor flow rate

[foxt]

Apologies if this has been asked and answered before - I searched but came up empty. Am I able to calculate my alkalinity demand based upon the flow rate and alkalinity level of my Ca reactor effluent?

I know that I can hold alk steady at 8.0dkh if I run 90ml/min of effluent through the reactor, and the dkh of the effluent is around 13. So I am adding 5dkh at a rate of 90ml/min to keep things steady, but I get lost a bit trying to take it from there to my daily alk consumption? Anyone?

 

[Brew12]

Apologies if this has been asked and answered before - I searched but came up empty. Am I able to calculate my alkalinity demand based upon the flow rate and alkalinity level of my Ca reactor effluent?

I know that I can hold alk steady at 8.0dkh if I run 90ml/min of effluent through the reactor, and the dkh of the effluent is around 13. So I am adding 5dkh at a rate of 90ml/min to keep things steady, but I get lost a bit trying to take it from there to my daily alk consumption? Anyone?

I've never given it much thought, but you should be able to if you know your tank volume. Adjust your flow rate to alkalinity added over 24 hours. So, you are adding 64,800ml/day with a 5dkh increase. 64,800ml is 17.12 gallons. So, if you had a 17.12g system you would be adding 5dkh per day. If you have 85.6g of water, you are making up 1dkh per day.

 

[Foothill Corals]

Just turn it off for 24 hours and measure the drop in Alk.

 

[foxt]

Thanks!

My system volume is 300 gals. I am circulating about 34 gals of effluent per day at +5dkh (that's 2x your 17gal, you must have hit the wrong key on the calc, but I appreciate the help!). That works out to about 11% of system volume. So, am I using 0.11 x 5dkH=0.65dkh per day?

 

[foxt]

Just turn it off for 24 hours and measure the drop in Alk.

Yup, that would work but if there is a way to estimate it without experimenting I'd prefer that. Just trying to get a sense of the current level so that I can have a rough starting idea of what I need to dose if my reactor is offline for any reason.

 

[Brew12]

Thanks!

My system volume is 300 gals. I am circulating about 34 gals of effluent per day at +5dkh (that's 2x your 17gal, you must have hit the wrong key on the calc, but I appreciate the help!). That works out to about 11% of system volume. So, am I using 0.11 x 5dkH=0.65dkh per day?

Good catch! Glad I typed out the numbers!

So thinking out loud again. 34g @5dkh would be 170g @ 1dkh or 300g @ .57dkh

I need to think about why our two methods don't agree....

 

[foxt]

Good catch! Glad I typed out the numbers!

So thinking out loud again. 34g @5dkh would be 170g @ 1dkh or 300g @ .57dkh

I need to think about why our two methods don't agree....

Oh, they don't agree because I can't do math - 11% of 5dkH is 0.55dkH, not 0.65dkh! I was rounding my 11%, so it's all tied out when you use a calculator.

Thanks again!

 

[Brew12]

Oh, they don't agree because I can't do math - 11% of 5dkH is 0.55dkH, not 0.65dkh! I was rounding my 11%, so it's all tied out when you use a calculator.

Thanks again!

;Hilarious;Hilarious;Hilarious;Hilarious

Together we aren't too bad at this math and chemistry thing!