Alkalinity dropping even with increasing dosage.

[Joe Batt]

Are you sure your dosers are actually dosing what you think they are? 2 things happened to me.

1. I forgot that i needed to double dose the mixed 3a/3b solution
2. One of my dosers was pulling air and not actually dosing.

That can play with your mind and the results do not make sense. @William DeCoursey post is exactly what can happen. You are basically not dosing evenly and buffering something or precipitating something else.

I am dosing 3a/3b separately, and have checked the doses calibration and output. Thank you for your input though

 

[Joe Batt]

Your triton solution is likely bad. You should be higher in ph when dosing a lot of alk

This is a possibility that I will have to check.

 

[Joe Batt]

Sounds like you've been thorough in ruling out the more obvious stuff. My only other guess is an issue with the dosed product. Maybe try using a different alk solution to rule out one more variable?

Good luck sorting it out, thank you for posting the details of what you've already investigated

This is my next step, thanks for your input.

 

[Joe Batt]

You're running a much, MUCH, more advanced setup than me. FWIW, same happened to me. Alk/Calc demand went from moderate to out of control and well beyond what one would expect on a 4 mo tank. I don't know how I overdosed it initially, but in my case, that was the problem. Too much supplementation lead to precipitation. Tiny white crystals started to appear on the rock and in the sand. It was barely noticeable. The interweb tells me that these crystals aggressively suck further calcium and alkalinity out of the water. In my case, the solution was to stop supplementing entirely for a painful 3-4 days. Mag wasn't the issue, but I punched it up to 1450 anyhow and began dosing calcium and alkalinity very slowly again after letting it bottom out at 6.5 dkh. After about a week, I'm back to 9.5 dkh and a daily alk demand of .9dkh, which seems reasonable to me.

No idea if this is your issue, but a BRS vid I watched labeled this is the "most common" scenario leading to apparent runaway alkalinity demand.

This could well be the problem.

I had a return pump failure a couple of weeks ago when I was away. The dosing was just going crazy since it was now in the much smaller volume of the sump with no corals since it was in effect disconnected from the display for nearly 48 hours.

I got home, sorted out the return and fortunately hadn’t killed everything. I lost a few corals but the remaining corals requirements would have decreased drastically. When the return was sorted the total missing 48hr dose in the sump would have been added to the main display as it kicked back in circulating the water. The corals seemed OK and the Kh was Ok but demand steadily increasing.

This could well be the result. I have turned off all dosing for 24hours and will let the Kh fall, as per the BRSTV guidance. Will check again in 24hrs and dose back to the original level.....Fingers crossed!

 

[Ktran350]

I’m running into the same issue as well. I think I figured out what my problem was. My doser was dosing too much Alk at one time even though it was 60 ML of Alk which was spread over a 24 hr period (on the hour every hour, number of total doses = 24 at 2.5 ML per dose).

I recently got an apex dos which further increased my number of dosing over the same 24 hr (60 ML total; number of total doses = 85, at .7 ML per dose per day). Have you looked at this as a possible issue? Slower dosing of 2-part?