Sudden Drop in pH (and Drop in ALK plus Other Changes)

https://www.triton.de/en/

Dr. Jim

Well-Known Member
View Badges
Joined
Nov 30, 2019
Messages
603
Reaction score
383
Location
Farmingdale, NJ
I've had several parameters change suddenly in the past few days but I've made several changes during this time as well. Some parameter changes I understand, some I don't. I will list the changes in parameters first, then list the changes that I've made that somehow caused them, and then a discussion.

60gal cube set up for 10 months; 50 SPS frags.


Changes in parameters (over past 2-3 days):

-pH suddenly dropped from 8.16-8.35 to 8.06-8.25 (most troubling).
-Alk dropped from about 8.4 to 7.4
-Protein skimmer greatly reduced foam production
-NO3 dropped from about 17-20 to about 12-15 (a good thing; aiming for 2-5).
-PO4 dropped from about 0.08 to 0.03 (now dosing a little PO4; aiming for 0.04-0.06).

Changes I made in past 3-4 days:
-Switched from Triton 4-Part to Tropic Marine 3-Part Balling Method; Dosing Mg separately and TM Trace Elements A and K separately (and very sparingly). (Will write up reasons in a different forum).
-Added 1 cup chaeto to HOB refugium. (Chaeto has died 3 times in past 7 mo).
-Started using ZeoVit START and FOOD (vinegar smell).
-Closed windows (due to cold) but skimmer is plumbed to window.
-Added 3" sand (bottom half oolyte; top half slightly coarser) 2 months ago. NO3 seemed to have gone up from 5-10 to 15-20 as a result. Added burrowing snails 4 days ago.
-Started dosing saturated Kalk during the night: every 2 hrs for 6 doses of 2 ml each. (40 gal system)

Discussion and Questions

The drop in Alkalinity is easily explained by the new "learning curve" that came with switching 3-Part systems, but why would the pH drop so much? Unless I'm mistaken, the alkalinity level doesn't "control" the pH, correct?. Instead, pH is dependent on CO2. Although I closed windows, I still have outside air piped to the skimmer. (I will check for leaks, but this seems like it would be too much of a coincidence to start leaking right when all the other factors took place).

Next, why would the skimmer suddenly reduce foam production? The DC skimmer pump had always been set at 40% with the gate valve wide open. Now, I can set it at 95% and close the gate valve a little, and foam still doesn't rise. It has been like this for 2 days. Today (Day 3) it is starting to foam a little, perhaps as a result of me slowly raising the Alk?....now at 7.7.

The lower NO3 and PO4 can more easily be explained: i'm guessing it is due to the ZeoVit START and FOOD. (If so, these products seem to be a great way to lower NO3....in just 2-3 days!

Thanks for any comments.
Tank 10.28.20.jpg

Before anyone says "frags are too crowded", let me explain: I'm planning to move in about a half year and am just getting a "head start" for my "dream tank."
 
The Best reef aquarium LED lighting

Mastiffsrule

Where ever you go, there you are, so be nice 2 you
View Badges
Joined
Feb 10, 2019
Messages
7,789
Reaction score
31,196
Location
Charlotte
Hi @Dr. Jim

So first I want to say I do not see anything so alarming I would start immediate water changes or anything like that. You made some changes that should be expected to impact your #’s. I would not overly worry about the ph, or even alk too much. Rapid alk shifts are more concerning than PH. The change have been made, I would now work to get stability in the tank. Watch the kalk dosing by testing until you get a good dosing schedule down.

The problem with the amount of frags you have is not so much the space as you needing to figure out the daily alk consumption. I would highly recommend getting a good dosing schedule set up. You have a lot of money in there, you want to keep it stable.
 

scardall

Valuable Member
View Badges
Joined
Oct 23, 2007
Messages
2,342
Reaction score
1,411
Location
Cocoa, Florida
Alk and PH connected. Corals are causing your alk. to lower indirectly. No biggy just add alk. solution. monito alk. regularly and add alk sol. then your alk. will stabilize abit. keep on top of it. I have to with my tank. Use a log book so you can see your usage trend. Have fun.
 
OP
Dr. Jim

Dr. Jim

Well-Known Member
View Badges
Joined
Nov 30, 2019
Messages
603
Reaction score
383
Location
Farmingdale, NJ
The corals haven't been affected by the changes so I'm not too worried about them.

I started this post mainly out of curiosity. I'm curious as to what would make the pH suddenly drop. Again, is it because of the drop in Alk? (I have been thinking that Alk wouldn't cause this pH change, but rather CO2 in the water and/or air. But perhaps lower alk is causing CO2 to rise in the water?)

And, I am curious as to what would cause the huge change in skimmer performance.
 

Macdaddynick1

Valuable Member
View Badges
Joined
May 20, 2014
Messages
1,339
Reaction score
1,571
Location
Reseda, California
The corals haven't been affected by the changes so I'm not too worried about them.

I started this post mainly out of curiosity. I'm curious as to what would make the pH suddenly drop. Again, is it because of the drop in Alk? (I have been thinking that Alk wouldn't cause this pH change, but rather CO2 in the water and/or air. But perhaps lower alk is causing CO2 to rise in the water?)

And, I am curious as to what would cause the huge change in skimmer performance.
Check out BRS videos on both alkalinity and Ph. They explain the relationship pretty well.
 
The Best reef aquarium LED lighting

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
40,388
Reaction score
28,558
Location
Arlington, Massachusetts, United States
All other things unchanged, an alk drop that the oP saw from 8.4 to 7.4 dKH willc ause about a drop of about 0.06 pH units.

The OP reported a drop from [ 8.16-8.35 to 8.06-8.25 ] which is an average drop of about 0.10 pH units.

So it is likely to be partly the alk drop, and maybe partly something else.

Different two parts can have different effects on pH, depending on how the mix the alk part. The kalkwasser will tend to be boosting pH.

Using anything with vinegar in it can drop pH a bit.

Closing windows will tend to lower pH.

Could be any or all of these added together.
 
OP
Dr. Jim

Dr. Jim

Well-Known Member
View Badges
Joined
Nov 30, 2019
Messages
603
Reaction score
383
Location
Farmingdale, NJ
All other things unchanged, an alk drop that the oP saw from 8.4 to 7.4 dKH willc ause about a drop of about 0.06 pH units.
This is what I was looking for......thank you Randy. If it is easy to direct me to equations and a discussion as to why this happens, that would also be appreciated.

The Alk is now up to 7.7 but the pH dropped to 8.02 during the night which is the lowest I've seen it in a long time. (Alk goal is 8.0; considering the large discrepancies amongst brands of Alk test kits, I'm guessing that would get me in the range of 7.8 - 8.2).

In regard to the skimmer issue I discussed, I just want to mention that it seems to be back to normal (where I had to lower the DC skimmer pump down to 50%). I guess it will remain a curiosity as to why it stopped producing foam for a 3-day period that coincided with the changes that occurred due to the switching of 3-Part solution brands.
 

Randy Holmes-Farley

Reef Chemist
View Badges
Joined
Sep 5, 2014
Messages
40,388
Reaction score
28,558
Location
Arlington, Massachusetts, United States
This is what I was looking for......thank you Randy. If it is easy to direct me to equations and a discussion as to why this happens, that would also be appreciated.

I discuss the issue in detail here:


In simplistic terms, pH has a logarithmic relationship to alkalinity, so a doubling of alkalinity (say, 6 to 12 dkh) would increase pH by about 0.3 pH units and a ten-fold rise in alkalinity (which we do not encounter) would result in a 1 pH unit rise in pH. That assumes everything else is kept constant (such as CO2 levels in the water).
 
https://www.triton.de/en/

Have you heard about our Toys For Kids Drive?

  • YES

    Votes: 106 61.3%
  • NO

    Votes: 67 38.7%

Online statistics

Members online
2,323
Guests online
7,046
Total visitors
9,369

New Posts

Tunze
Top