Water changes - Salt mix with high dkh

[RaymondL]

I have dkh around 8.7 on average. I'm using Instant Ocean Reef Crystals, which have a dkh of 11.2 or so. So whenever I do a water change, it changes the dkh value from 8.7 to 10.8.

How can I minimize or mitigate this dkh fluctuation from water changes, which the mixed replacement salt water has a different dkh than the tank water?

 

[CasperOe]

Buy a salt mix that matches the parameters you aim to keep in your tank. That's far the easiest way if you want to avoid these swings.

Different mixes have different compositions. I has Tropic Marin Pro Reef with alk around 7.5-8.

 

[Miami Reef]

I have dkh around 8.7 on average. I'm using Instant Ocean Reef Crystals, which have a dkh of 11.2 or so. So whenever I do a water change, it changes the dkh value from 8.7 to 10.8.

How can I minimize or mitigate this dkh fluctuation from water changes, which the mixed replacement salt water has a different dkh than the tank water?

I don’t believe that’s possible unless you are changing a very large percentage of water.

Either buy a lower alk salt, or use an acid to reduce the alkalinity in the mix prior to using it.

Sodium bisulfate: https://www.reef2reef.com/threads/s...in-new-salt-water-or-in-display-tanks.362825/

Muriatic acid: container size in gallons x dKH drop x .123= mL of muriatic acid to be dosed.

When using either acid, you need to heavily aerate the container for a day to bring back up the pH.

 

[rtparty]

What Miami said. You’d have to be changing 90% of your water to spike the alkalinity that high with every change.

Change 10% at a time or change salts completely. Either is fine

 

[gbroadbridge]

I have dkh around 8.7 on average. I'm using Instant Ocean Reef Crystals, which have a dkh of 11.2 or so. So whenever I do a water change, it changes the dkh value from 8.7 to 10.8.

How can I minimize or mitigate this dkh fluctuation from water changes, which the mixed replacement salt water has a different dkh than the tank water?

If you're doing a 10% water change, the effect on your tanks alkalinity using the 11.2 dKh water would only be 0.25dKh - raising your tank to about 9dKh

It would only be 0.5dKh even if you performed a 20% water change.

Either change will not bother anything in the tank, as most tanks vary by more than that over a 24 hour period.