pH crash has me scratching my head

[recess62]

The pH in my 90 with 40 gal sump has been stable for months. For some reason on Sept 2 there was a "crash". I have not been able to ID the reason. I changed carbon, GFO, and added biopellets on 8/30. I have been using vibrant weekly for the past month for a slight GHA outbreak. Otherwise no other changes I can ID

Current parameters
Alk 8.4 Hanna
Nitrate 5 salfert
Phos .05 Hanna ulr

I have recalibrated probe x 2. Been doing 20 gal water changes every other day. I even installed a Co2 scrubber on the airintake on the skimmer. Two interesting observations. First is that my Alk consumption has greatly decreased. Secondly is that my Chaeto has taken a huge hit probably from the vibrant. I was thinking that maybe the vibrant has done something to the photosynthetic flora in the tank which has greatly affected Co2 sequestration.

Any other thoughts?

 

[WesleyC]

Did you have a big party with lot of people in the room that day?

When you recalibrated the probe x2, was that to confirm your pH reading is correct? Reason I ask is that I had similar thing happened. My pH dropped for no reason. So I calibrate my probe and found out that the low pH was just false reading. But couple of days later, pH dropped again. So I calibrate again, and found out that the probe just could not hold the correct reading any more. I had to replace the probe.

 

[recess62]

No parties. I wish it was that easy. Yes I calibrated to confirm the correct reading.

 

[Justin Swinney]

I have been using vibrant as well for gha no noticeable swings have had some chaeto die off but that could be because it's being out competed by the ulva in my fuge

 

[recess62]

I have been using vibrant as well for gha no noticeable swings have had some chaeto die off but that could be because it's being out competed by the ulva in my fuge

ULVA???

 

[GoVols]

Did you have a big party with lot of people in the room that day?

When you recalibrated the probe x2, was that to confirm your pH reading is correct? Reason I ask is that I had similar thing happened. My pH dropped for no reason. So I calibrate my probe and found out that the low pH was just false reading. But couple of days later, pH dropped again. So I calibrate again, and found out that the probe just could not hold the correct reading any more. I had to replace the probe.

I had to replace an Apex temp. probe that went bad.

 

[Justin Swinney]

ULVA???

Yeah. Ulva sp. also known as sea lettuce. Your algae eating fish will eat it as well so that's a plus instead of getting rid of it you can feed it

https://www.algaebarn.com/product/sea-lettuce-ulva-sp/