A silly water change question

[William Sharkspeare]

My tank has been set up for about a month now with just live rock and 5 chalk bass in a 240. I do not currently have a fuge or any reactor and my nutrients are getting high.

​

PO4 .39​

NO3 11.4​

​

I have Tropic Marin Pro salt which has low alk. I imagine I would increase the alk of the new water before adding it to the tank? I have BRS soda ash.

Thanks

 

[Gumbies R Us]

Just do your water change normally and dose the soda ash after the fact. That is what I would do.

 

[Randy Holmes-Farley]

What tank alkalinity are you targeting?

 

[William Sharkspeare]

I also have B Ionic.

9-10 ish maybe?

I would like to do LPS and hopefully a Monti.

pH was around 8 (salifert) this morning before the lights came on. Alk is 8.9 (hanna)

 

[Randy Holmes-Farley]

A 10% change with 7 dKH water only drops alk from 9 dKH to 8.8 dKH, so it’s no big deal, but adding some baking soda after the change is a fine plan.

 

[William Sharkspeare]

Sounds good, thank you sir. For future reference, what would the change in alk be with a 20% change?

 

[Dom]

Sounds good, thank you sir. For future reference, what would the change in alk be with a 20% change?

If 10% drops it from 9 to 8.8, then I would think 20% would drop it from 9 to 8.6, but not 100% on this.