SPS Bleaching due to alkalinity swing seeking advice

Matthew Dambra · Feb 11, 2018

Hello all,
Recently my alkalinity rose from 8.5DKH to 9.5DKH seemingly overnight this morning i awoke to a lot of corals starting to bleach out and my LPS receding dramatically.
Im not exactly sure how it rose so sharply when i did not change my dosing pumps amount but the guidance i am seeking is my actions to correct it.
Should i just turn my dosing pump off and keep checking the alk till it goes back down to around 8.5 or should i do some water changes and attempt to lower it more quickly. I think trying to lower it down too fast will just add to the stress and bleaching.
If anyone has had a similar experience or any advice it would be greatly appreciated.

Finhead · Feb 11, 2018

Yes just shut your dosing pump off and let it fall naturally.

Tommy's Reef · Feb 11, 2018

Only 1.0 dkh is not to bad.
If it' happening all the time it could be a problem but just one rise overnight, unlikely. Especially went u say lps receding in one days time, that's pretty quickly for them to react. Look for another problem like temp or stray electric current etc?
Also make sure u test alk the same time as u did the day before.

Yati · Feb 16, 2018

To piggy back off @tommyhere 1.0 swing wouldn't have that effect overnight, there is a underline gradual effect that is being overlooked. If you think its really the DKH stop dosing and you can also do a small water change. Test your parameters, have them tested from you LFS if needed.

reefwiser · Feb 16, 2018

What I have found is that DKH swings because the corals change in their uptake due to their health. When corals are first placed into a tank it can take up to a month before that begin to grow and start up taking cal and alk. Introducing corals to a tank can cause other corals to stop their growth also for a time. So you can chart how your corals health is doing by how your alk reading is from day to day. So actually the swing upwards her is due to the corals health stopping the uptake of alk and cal and the bleaching is due to the health and not from a rise in alkalinity.