Alk spike after water chance with Instant Ocean

[SoCalVictor]

After doing a 40g water change on my 230g system, my alk spiked from 8.4 to 10.2. pH and calc remained similar at 8.2 and 400

I use instant ocean salt and I know it sometimes has high alk, freshly mixed, but drops down to 9 after a couple of days. Same routine this time, I mix and then wait a couple of days.

When I was done with my water change, luckily it was time for my trident to test and that’s when I got the alert. I had some residual mixed water in the mixing container and tested that and it tested 10.6 on my hanna.

a couple of questions
1. Should I be concerned and should I try to adjust the alk down? I have a mixed tank with sps, lps, softies and fish
2. Did I just get a bad batch or did I need to wait a bit longer? It was a fresh bucket I used and I rolled it before using it
3. Why was the alk spike so high if the freshly mixed water was 10.6 and I only did a less than 20% water change?

 

[joseserrano]

Stop dosing and let the alk drop on its own

 

[Randy Holmes-Farley Verified Community Expert]

After doing a 40g water change on my 230g system, my alk spiked from 8.4 to 10.2. pH and calc remained similar at 8.2 and 400

I use instant ocean salt and I know it sometimes has high alk, freshly mixed, but drops down to 9 after a couple of days. Same routine this time, I mix and then wait a couple of days.

When I was done with my water change, luckily it was time for my trident to test and that’s when I got the alert. I had some residual mixed water in the mixing container and tested that and it tested 10.6 on my hanna.

a couple of questions
1. Should I be concerned and should I try to adjust the alk down? I have a mixed tank with sps, lps, softies and fish
2. Did I just get a bad batch or did I need to wait a bit longer? It was a fresh bucket I used and I rolled it before using it
3. Why was the alk spike so high if the freshly mixed water was 10.6 and I only did a less than 20% water change?

The reported numbers do not seem to add up.

Are you using tap water to make the salt water?

Otherwise, I don't see how that large of a rise is possible for that size water change. If the tank is 8.4 dKH and the water change was about 20%, the alk in the new salt water would need to be 17.4 dKH to give a 1.8 dKH rise.

 

[chipmunkofdoom2]

What Randy said. Something is wrong here. You say the left over Instant Ocean tested at 10.6 dKh? If that is true, your tank would have risen to 8.78 dKh, not 10.2 dKh.

I suspect the Trident is wrong. 10.6 dKh is what Instant Ocean usually is, so that makes sense. Did you drain your sump during the water change and put all the new Instant Ocean in the sump? Is it possible the Trident pulled almost all new saltwater for its test?

 

[nanonøkk]

The reported numbers do not seem to add up.

Are you using tap water to make the salt water?

Otherwise, I don't see how that large of a rise is possible for that size water change. If the tank is 8.4 dKH and the water change was about 20%, the alk in the new salt water would need to be 17.4 dKH to give a 1.8 dKH rise.

i used rodi water this time but i think it was one of my mixing containers with residue

 

[Privateye]

If your IO salt produces 10.6 dKH, I want some of that batch!

 

[nanonøkk]

i used rodi water this time but i think it was one of my mixing containers with residue

i’m so sorry about this i forgot i followed this because i used the same salt and i had an alk spike i’m so sorry

 

[Daveobrien]

By any chance do you have a calcium reactor, and touch it in any way? Increase in CO2, cleaned/changed reactor media/increase effluent rate, lower the pH target? Do you have a pH monitor on the reactor?

Or, how about a KALK reactor. Clean it, new fresh media, ... Anything?

I just spiked my Alk... And you can guess what I did to cause it.

 

[SoCalVictor]

I know that the numbers don't add up either which is why I'm puzzled.

I use RODI. I will caveat that the residual water was pretty low so I'm not confident I got the best sample water.

I verified the trident reading with my hanna alk and they were pretty closely aligned.

I did empty out of my sump and filled it via the sump but the trident ran its test about 15 minutes after my water change. However 30 more minutes later, it went to 9.3. 12 hours later it was at 8.9.

No KALK or Ca reactors.