DKH spike

jrb1021 · May 25, 2021

My tank has been up and running and very stable for about 4 years. It's a 150 gallon with a 75 gallon sump. I have been running BRS 2-part with TropicMarin balling trace elements since it was about a year old. DKH has always been in the range of 7.5 to 10, mostly hovering at 8.5 at 7cc/hr x 12hr/day mixed as per package directions. I haven't changed anything--same salt mix, no new livestock additions, nothing.
Suddenly I am running DKH levels of 13ish. I decided the pump had given out and replaced it, recalibrated, and tested it for accuracy. It's accurate. I performed a partial water change, decreased the 2 part, and decreased it again. It's still 13ish. I have now shut the two-part all the way off and will just monitor levels. Has anyone experienced this? Does anyone have any ideas? I'm afraid these levels are going to cause problems sooner than later. Thanks in advance.

vabben · May 25, 2021

How are your other parameters? Sounds like something is upsetting your coral and they are now not taking up as much DKH.

I have experienced this once, I found there was some stray voltage from a small pump in my sump. Once I removed the pump my coral began uptaking the DKH again.

jrb1021 · May 25, 2021

Other parameters appear to be OK. The corals on the right side of my tank are thriving. I am noticing dieback only on the left side, Given the flow in the tank, it makes no sense to me and I have no idea how to troubleshoot it. Grateful for any help.

Randy Holmes-Farley · May 25, 2021

Might you have closed up windows due to heat, and the pH dropped, reducing demand?

jrb1021 · May 25, 2021

The house is climate controlled with A/C/heat year round. I have automatic skylights that open for ventilation several times a day and which are hooked to a sensor which open additionally with a rise in measured CO2. I don't think that's the answer. Thank you.

Randy Holmes-Farley · May 25, 2021

Then either you have been dosing more than you previously did, or the tank is not using as much for some other reason.

Are you dosing nitrate? (that adds alk)

Top off water is what?

You may never figure it out, but for now, stop all dosing while it decline son its own (assuming you want it lower).

jrb1021 · May 25, 2021

Randy Holmes-Farley said:
Then either you have been dosing more than you previously did, or the tank is not using as much for some other reason.

Are you dosing nitrate? (that adds alk)

Top off water is what?

You may never figure it out, but for now, stop all dosing while it decline son its own (assuming you want it lower).

I am not dosing nitrate. Unless the dosing pump is malfunctioning still--and I've tested it as accurate, I am using less than I previously was (it had been 7cc/hr x 12 hours, then 5 then 3. This morning I shut it off completely. Top off water is RO/DI via Apex ATK. I definitely want it lower--the fish and soft corals seem to be thriving but the SPS is visibly very unhappy.

Randy Holmes-Farley · May 26, 2021

jrb1021 said:
I am not dosing nitrate. Unless the dosing pump is malfunctioning still--and I've tested it as accurate, I am using less than I previously was (it had been 7cc/hr x 12 hours, then 5 then 3. This morning I shut it off completely. Top off water is RO/DI via Apex ATK. I definitely want it lower--the fish and soft corals seem to be thriving but the SPS is visibly very unhappy.

Assuming you believe the alk test, then I'd stop dosing and let it decline.