How Can I Lessen a Daily pH Swing

[cdness]

So I know chasing the target pH number is a big no-no and stability is key. However I am having a swing that no matter what I do will not get any better... I am looking for opinions, suggestions, or a general where am I going wrong...

Here is the graph from yesterday from Reeftronics. If you want to see the history, check it out as it is freely available: Apex Status « Reeftronics

Parameters:
Salinity: 1.026 - ATC Refractometer
Calcium: 440 - 460 - Red Sea
Alk: 9 - 10 - Red Sea
Magnesium: ~ 1440 - 1460 - Red Sea
Phosphates: .02 - Hannah
Nitrates: Undetectable on API kit

Cal and Alk maintained by BRS dosing pumps spread out through the day. Alk is BRS Soda Ash in solution...

Here's what I have tried:

1. Increased flow in the display by adding powerheads

2. CO2 Scrubber on an MSX 200 skimmer. I exhaust the media in a day or two so it is not cost effective.

3. Added a fan to the stand to cycle the air inside the stand

4. Ran the skimmer feed line higher in the room and to a different room - no effect. Unable to run to outside for multiple reasons (location of tank, mosquito spraying by city, use of fertilizers in the area)

5. I added numerous houseplants to the place

I am running out of ideas and just looking for additional opinions or ideas. If I should just ignore the swing let me know, but it seems to get pretty low at times during the day so I want to make sure I am not causing harm in the tank...

 

[mcarroll]

Unless the corals or fish are giving you a sign, I'd be very inclined to watch but do nothing.

But since you already have plants, lighting them should cause them to respire faster...they need to be on a flipped lighting cycle though, which could be tough. (The plants may end up with 24x7 lighting...no idea if they'd care.) Only do this if you already have the lights though.

-Matt

 

[pickupman66]

I agree with Mcarroll. So long as your corals and fish are happy, dont worry about it. I would prefer mine be higher than it is, but it is what it is.

I will however say that mine seems to be a much more uniform curve than yours is in the long term as well. my alk is about 11 I believe. I havent tested sine the water change thrusday. here is a comparison on a monthly basis.

Mine

Yours

 

[JOKER]

I reduced mine with a display fuge but it still swings some.

 

[Aquanaut WA]

When was the last calibration done? I find it hard to believe your numbers with the salinity and other perams. Probes can also be affected by stray voltage. A way to test is to remove a isolated water sample and test that. Something is drawing it down. High calcium 430+ can lock up alk and drive ph down too. Stable Alk 8.5-10dkh is more of a concern and flow for SPS.

 

[cheezybuda]

Try running chaeto in your fuge with a 12-16 hour light cycle opposite of display lights. I was able to get my tank to tighten up the curve by about .18 (.9 on each end)

 

[cheezybuda]

I mean .09 on each side

 

[cdness]

Last calibration was done a month ago, but it doesn't help. The probe reads perfect when placed in the calibration fluid. I have tested a sample in a jar as well just to be sure.

Fuge is on opposite light cycle. I have tried following exactly what my lights are doing, 16 hour cycle, 24 hours per day, etc with no change...

 

[choff]

Agree, chaeto. The fuge on an opposite cycle has held me quite a bit.

 

[jduck]

Fuge on opposite light cycle, or dosing kalk at night

 

[JOKER]

What if you add a little more light to fuge

 

[CastAway]

Luke says to Obi-Wan, "what about ozone"?

 

[gtbarsi]

What about using Kalk in your top off water, it raises PH, and will lower the amount of Cal and Alk you have to dose. If you do not want to use it with an ATO, to avoid raising PH during the day, and your evap rate is fairly consistent you could setup a dosing pump and dose Kalk throughout the night. It might cause a tiny swing in salinity but you could manage that by controlling the concentration of Kalk...

 

[cdness]

I have considered Ozone... However I think a 125G tank is a bit small for it, don't you think?


I have run Kalk in the past. I would more than likely have the ATO only run during the low PH times if I did that. I think I would prefer it in a reactor though and not in the top off reservoir...

 

[mcarroll]

After all that you've tried, I hate to ask, but...have you actually confirmed that the cause is CO2 buildup in the house?

For example, have you opened an outside window and put a fan in it to blow fresh air into the tank room? You may not be able to operate the tank like this all the time, but you WOULD get results and as a test you could use it as a confirmation (or not) of the issue.

If it's really a CO2 problem, then piping in fresh air via skimmer (using a better forced-air method) is probably worth looking at more seriously. It can definitely be done without impact to the houses HVAC system or leaving a wndow open, etc.

But to reiterate, if the coral and fish are happy as-is, then it's likely not worth the trouble.

-Matt

 

[mcarroll]

BTW, what happened between 7/27 and 8/4 in your chart above? Water chane(s)? Etc?

pH was pretty steady through that period.....maybe you need to look at a longer time frame to see what "normal" is?

-Matt

 

[cdness]

BTW, what happened between 7/27 and 8/4 in your chart above? Water chane(s)? Etc?

pH was pretty steady through that period.....maybe you need to look at a longer time frame to see what "normal" is?

-Matt

The house was empty during this time. We were at a family reunion. PH was super stable.

I can almost guarantee it is CO2 in the house... We have window AC units and hot water heat so no forced air circulation and no fresh air venting.

The tank is sitting on a middle of the house wall. It is at least 20 feet from the nearest window each way not counting the distance to run a tube to the skimmer. Plus there is no way to hide the tubing even if I could. If you have other options let me know. By the way, we are renting

 

[CastAway]

I would not think 125 is too small for ozone. In fact, in my ignorance, I would not think system volume would be a significant variable in the decision. But, your question may compel me to research a little. My thought was to dose ozone to your skimmer on the pH peaks only, to see if your pattern would flatten out little. It would be like treating a symptom instead of the cause, but it may work. Although you're object is not really the ORP, there may be some ancillary benefits.

Again in my ignorance, I find it interesting that during the time the house was empty, and I'm assuming the tank was basically hands free, that the swing was less although the values were higher. Can you tie the actual peak to any specifc action? Is it lights out? Is there any correlation to anything else, like your dosing times?

 

[feh]

The only time I see things being remotely close to a bad place is after lights out. Do you have a fuge? Running a refugium with the lights on at night can help counter low pH swings at night. The macro algae will help maintain the pH levels by using the CO2 dissolved in the water.

 

[beaslbob]

Ignore it.

your alk is fine.

Some minor daily variences in things like pH are normal and actually healthier then a constant, no change, pH of lower value.

my .02