Water change alkalinity question

[Hockeypunk1]

My alkalinity has slowly been dropping due to my calcium reactor not keeping up with demand, and me being a bit lazy and not making up for the difference. My reef looks great and all my sps are actually thriving at 4.8 DKH! I am planning to clean out my calcium reactor today and I was thinking about doing a water change. I have reef crystals mixed up at 9.9 DKH. What would the alk swing be on approximately 20% water change?

 

[p1u5h13r4m24]

I’d probably do a 10% and k think that would take you to 5.0. Why don’t u add kalk to a doser or ssomething to prevent this. Also Red Sea blue mixes a bit lower around 8.0 dkh

 

[Randy Holmes-Farley Verified Community Expert]

0.2 x 9.9 + 0.8 x 4.8 =5.8 dKH

 

[p1u5h13r4m24]

0.2 x 9.9 + 0.8 x 4.8 =5.8 dKH

Thank you wanted to edit my answer, but this app doesn’t let you edit post am I’m too lazy to search for the post on the browser

 

[Hockeypunk1]

I’d probably do a 10% and k think that would take you to 5.0. Why don’t u add kalk to a doser or ssomething to prevent this. Also Red Sea blue mixes a bit lower around 8.0 dkh

Thank you! I used to have a doser, but I have had great results with a calcium reactor. I have been manually dosing soda ash once or twice a week. I just don't test as often as I should! Lol! It's crazy because my across all look amazing! My coral grow like weeds and everything looks good besides a touch of hair algae in a few places. I don't mind raising it 1 DKH and then l will slowly raise it back to 7-8.

 

[p1u5h13r4m24]

I’d probably do a 10% and k think that would take you to 5.0. Why don’t u add kalk to a doser or ssomething to prevent this. Also Red Sea blue mixes a bit lower around 8.0 dkh

Thank you! I used to have a doser, but I have had great results with a calcium reactor. I have been manually dosing soda ash once or twice a week. I just don't test as often as I should! Lol! It's crazy because my across all look amazing! My coral grow like weeds and everything looks good besides a touch of hair algae in a few places. I don't mind raising it 1 DKH and then l will slowly raise it back to 7-8.

Can we see a picture of your tank??

 

[Hockeypunk1]

Thank you wanted to edit my answer, but this app doesn’t let you edit post am I’m too lazy to search for the post on the browser

You can edit on the app. It's the drop down arrow next to the report button on the bottom left

 

[p1u5h13r4m24]

Thank you wanted to edit my answer, but this app doesn’t let you edit post am I’m too lazy to search for the post on the browser

You can edit on the app. It's the drop down arrow next to the report button on the bottom left

Are you on iOS?

 

[Hockeypunk1]

0.2 x 9.9 + 0.8 x 4.8 =5.8 dKH

That's amazing! Thanks Randy! What is the 0.8? That is the number that was keeping me from doing my own math.

 

[Hockeypunk1]

Can we see a picture of your tank??

I'm not at home but I'll post one later

 

[Hockeypunk1]

Are you on iOS?

I'm on Android

 

[p1u5h13r4m24]

Are you on iOS?

I'm on Android

Ya I’m iOS I think they are working on us iPhone users

 

[Hockeypunk1]

Ya I’m iOS I think they are working on us iPhone users

Ahh yes! I didn't think about all you iPhone users

 

[EricR]

...What is the 0.8?

That's the 80% of your original 4.8 dKH water left when doing 20% water change.

 

[Randy Holmes-Farley Verified Community Expert]

That's the 80% of your original 4.8 dKH water left when doing 20% water change.

Yes, nearly all parameters except ORP and pH will just be the weighted average of the new and old salt water. :)

 

[Hockeypunk1]

That's the 80% of your original 4.8 dKH water left when doing 20% water change.

That's really interesting! I would have thought it would be much more complicated

 

[Hockeypunk1]

Can we see a picture of your tank??

You'd never guess that my alk was so low!