dKH drop after water change

[Fringe09]

I've been using Tropic Marin PRO-REEF since I setup my tank almost a year ago. It's a 200 gallon mix-reef aquarium (more SPS than LPS).

I dose 5 ml a day of Ca and Alk using the Neptune DOS so I can keep my Alk between 7.7-8.1 dKH.

I perform a weekly 10% water change.

I've noticed lately that a day after a water change, my Alk drops sometimes by .3 or .4 dKH. I don't see any negative affects on my corals.

I'm temporarily increasing dosing until I reach 7.7-7.8 dKH and then scale it back. Any other suggestions on what to do?

 

[Crabs McJones]

I've been using Tropic Marin PRO-REEF since I setup my tank almost a year ago. It's a 200 gallon mix-reef aquarium (more SPS than LPS).

I dose 5 ml a day of Ca and Alk using the Neptune DOS so I can keep my Alk between 7.7-8.1 dKH.

I perform a weekly 10% water change.

I've noticed lately that a day after a water change, my Alk drops sometimes by .3 or .4 dKH. I don't see any negative affects on my corals.

I'm temporarily increasing dosing until I reach 7.7-7.8 dKH and then scale it back. Any other suggestions on what to do?

When you do your water change, do you know what the DKH is of your new water you're adding in?

 

[Fringe09]

When you do your water change, do you know what the DKH is of your new water you're adding in?

I'll test it next time. The description reads "To maintain the alkalinity in a 7-8° dKH range".

 

[Crabs McJones]

I'll test it next time. The description reads "To maintain the alkalinity in a 7-8° dKH range".

Variances in salt mix may be causing your alk to not mix what you think it is. My best guess is your salt is mixing up at a lower alk level then what your tank is, bringing your level down.

 

[Fringe09]

Variances in salt mix may be causing your alk to not mix what you think it is. My best guess is your salt is mixing up at a lower alk level then what your tank is, bringing your level down.

I am fairly certain the Alk mixes low, but will test next time to confirm. I guess I'll continue to temporarily raise the dosing amount for a day or two and then it scale it back.