Night time alk spike?

BroccoliFarmer · Jan 2, 2023

Ever since I did a water change (instance ocean reef crystals) on friday, I had an alkalinity spike as per my trident. Readings went from 8.6 ish up to 9.4. Normally, I would be running my kalk reactor and dosing maybe .8 of dkh per day..really low consumption. However, since I did my water change...my dkh has been over my threshhold for dosing kalk (roughly I dont dose when I am above 8.7) and I have had a weird pattern going on.

My midnight alk reading is 9.4 (dosing off). Throughout the day, my alk drops down to 8.9 (still dosing off). Then at midnight jumps back up to 9.4

Calcium is at 440, Mag is at 1450 (yeah yeah yeah..i know, a little high, but I cant lower it with IORC water changes...ive tried). My nighttime PH drops to 7.7 (I have an outside airline...cant get that up either regardless of what I try).

Any ideas on what could be causing this weird pattern? As of now, I have had no negative impacts from the alk spike...just really threw my tank patterns off and want to get things back.

Thank you in advance.

ナイトコア猫 · Jan 3, 2023

I would recommend verifying in the logs that the kalk indeed does not dose.

Is ATO triggering during the daytime measurement?

Do your pumps, including powerhead and main pump, have special day vs nite modes?—e.g., go into peaceful mode at nite, or is the day time scheme very turbulent (this discrepancy would be noted by looking at the overflow—my day and nite water levels within the overflow box are consistently different, and at nite, the sump Tunze sensors are a bit more submerged than day nite. This causes the salinity at nite to rise (because more evaporation may take place compared to day time). Higher nite salinity in turn imputes higher alk.

Also, you are not carbon dosing, correct? Feeding will bind alk away, whereas carbon dosing will free it for use.

This does not explain why it seemed to have happened after you performed a water change. Reading Randy Holmes-Farley's postings on such matters, I think Randy might say the readings are within the tolerance/precision of Trident.

I would re-check and verify both the code and the output to make sure the APEX does what code intends it to do.

Is your kalk dosing setup like so:

C-like:

Fallback OFF
OSC 000:00/002:20/057:40 Then ON
If Alk > 9.00 Then OFF

(Mine is setup so kalk is primary—dose as much kalk as possible, then fill remaining deficit with other methods using Trident control. I recommend also comparing ALK measurements to other occurrences during the day (things with the socket icon):

BroccoliFarmer · Jan 3, 2023

ナイトコア猫 said:
I would recommend verifying in the logs that the kalk indeed does not dose.

Is ATO triggering during the daytime measurement?

Do your pumps, including powerhead and main pump, have special day vs nite modes?—e.g., go into peaceful mode at nite, or is the day time scheme very turbulent (this discrepancy would be noted by looking at the overflow—my day and nite water levels within the overflow box are consistently different, and at nite, the sump Tunze sensors are a bit more submerged than day nite. This causes the salinity at nite to rise (because more evaporation may take place compared to day time). Higher nite salinity in turn imputes higher alk.

Also, you are not carbon dosing, correct? Feeding will bind alk away, whereas carbon dosing will free it for use.

This does not explain why it seemed to have happened after you performed a water change. Reading Randy Holmes-Farley's postings on such matters, I think Randy might say the readings are within the tolerance/precision of Trident.

I would re-check and verify both the code and the output to make sure the APEX does what code intends it to do.

Is your kalk dosing setup like so:

C-like:

Fallback OFF OSC 000:00/002:20/057:40 Then ON If Alk > 9.00 Then OFF

(Mine is setup so kalk is primary—dose as much kalk as possible, then fill remaining deficit with other methods using Trident control. I recommend also comparing ALK measurements to other occurrences during the day (things with the socket icon):

Happened again last night. I can confirm...my kalk reactor never got fed any RODI. The ONLY thing I can think it might be is at what PH does the water turn acidic and start disolving calcium carbonate? My PH drops to 7.7 and below at night and that is my only guess on what could be happening.

Randy Holmes-Farley · Jan 3, 2023

With an alk of 9 dKH, there won’t be any significant rapid dissolution of calcium carbonate at pH 7.7.

ナイトコア猫 · Jan 3, 2023

If not any of the things I guessed, then I would look to discover correlations between any inputs or sockets vs Trident, and debug that way. The most likely thing is probably coincidence of timing of ATO or flow pattern vs testing.