Alkalinity keeps falling- Help

[fishnugget1]

I have a 7 mo old tank with 5 fish and mostly LPS. I use the Apex doser. I want to maintain an alk level of at least 9.5 if not higher. No matter what I try the alk level keeps settling at 8.5 after a week. I keep adding alk once a week as well as my daily dosing. I am dosing 60ml of BRS alk and calcium. Calcium seems to hold at 425. Mag at @ 1400. I have a 175 gallon tank. Is it possible that I have to dose alk so much more than calcium on a daily basis?

Any comments would be appreciated. I am frustrated

 

[Brew12]

Following....

 

[reeferfoxx]

I keep adding alk once a week as well as my daily dosing

Can you clarify on this? You dose alk once a week or once a day?

Is it possible that I have to dose alk so much more than calcium on a daily basis?

Yes.

http://reefkeeping.com/issues/2002-04/rhf/feature/

"The primary reason that we care about alkalinity is that when organisms build calcium carbonate skeletons, they effectively remove calcium and carbonate from the water column. If we had a handy way to measure carbonate, or especially bicarbonate, which corals use as their source of carbonate, we would likely have little interest in alkalinity. Unfortunately, measuring bicarbonate directly is difficult. Measuring alkalinity is very easy, and we use it as a surrogate measure for carbonate and bicarbonate."

 

[fishnugget1]

I have an apex with a dos doser. I dose between 12:00am-8:am alk. I dose calcium rest of day. I do this daily. I also have a refugium with a reverse photo period. On same time as alk doser.

 

[cracker]

Following also, here is an interesting article concerning 2prt dosing.
https://joejaworski.wordpress.com/2014/05/19/the-right-way-to-use-2-part-additives/

 

[reeferfoxx]

I have an apex with a dos doser. I dose between 12:00am-8:am alk. I dose calcium rest of day. I do this daily. I also have a refugium with a reverse photo period. On same time as alk doser.

This is common. You have coral so they need calcium carbonate to grow. It takes alk and calcium to create calcium bicarbonate and carbonate. Without these two elements, corals would die. Your dosing regimen sounds good to me. I don't know what the issue is or you just don't understand why you are dosing?

For example, my tank uses 1.5dkh within a 24 hour period. I dose twice a day to maintain 8.5dkh. My calcium drops slower (maybe a little higher than yours) so I dose calcium twice a day but half the amount of alkalinity.