Ph issues

anarchy · Aug 23, 2015

Hey guys. Been talking to adam @Battlecorals about this weird ph issue I've been having and we havnt been able to figure it out so he sent me here.

The issue is my ph drops to around 7.6 each night and only gets up to about 7.8 during the day. I'm monitoring ph by lab grade ph probe and my apex. I just recalibrated them last week to make sure they were reading accurately.

I'm seeing no I'll effects on any of my sps or any other coral for that matter.

The tank
I have 2 displays. A shallow 30 and a 93 rimless
Sump diy 55 gal middle section fuge with tons of chaeto
Skimmer reef octopus nwb 150
Lighting 1 250w halide over each tank
Fuge light 2 bulb t5 1 6500k bulb and 1 magenta bulb
Sand is crushed coral

Current parameters
Alk 8.6
Cal 500
Mag 1400
Nitrates 0
Phos unsure
Salinity 1.025

Currently to get ph into the 7.8x range I have to open all my windows and turn the house fan on for an hour each day

Here's a screen shot of my apex from earlier

And from right now with the house fan on

And here's a current pic of the tanks

Greenstreet.1 · Aug 24, 2015

My ph has been the same way for months my hi 7.73 right now it's at 7.57 I don't see any problems with corals or fish so I don't worry about it. I think it may be caused by the cheato as my probe is in the same section as the cheato.

anarchy · Aug 24, 2015

My probe is in the chamber before my chaeto. It's with my skimmer and heaters and a few other pumps that run my Reactors and an air stone

ReefMadScientist · Aug 24, 2015

Hey anarchy.

I just had the same issue and I FINALLY fixed it thanks to Randy. See my thread below. As a quick recap, my house had too much CO2 in the den where my tank is. This is because its 115 degrees out and we have the house closed up. We do not have any fresh air coming. Long story short, I did a quick test to prove this is a CO2 issue and not an aeration problem. I then ran a air hose from my skimmer inlet to outside where my skimmer sucks in fresh air. I also ordered a CO2 scrubber from BRS but I really do not need it right at this point. I am averaging 7.9 to 8.0 pH.

https://www.reef2reef.com/threads/wanted-to-say-thanks-my-low-ph.210200/

anarchy · Aug 24, 2015

ReefMadScientist said:
Hey anarchy.

I just had the same issue and I FINALLY fixed it thanks to Randy. See my thread below. As a quick recap, my house had too much CO2 in the den where my tank is. This is because its 115 degrees out and we have the house closed up. We do not have any fresh air coming. Long story short, I did a quick test to prove this is a CO2 issue and not an aeration problem. I then ran a air hose from my skimmer inlet to outside where my skimmer sucks in fresh air. I also ordered a CO2 scrubber from BRS but I really do not need it right at this point. I am averaging 7.9 to 8.0 pH.

https://www.reef2reef.com/threads/wanted-to-say-thanks-my-low-ph.210200/

Thanks I'll read your thread. I exchange all of the air each day by opening windows in the basement where my tank is and turning on our house fan that pulls the air out of the house and the new air comes in through the basement windows. If I do this for an hour the pH comes up to 7.9 but by the next morning it's right back at 7.6, but if I don't do it for a few days it keeps creeping lower

anarchy · Aug 24, 2015

After reading I'll probably have to open my stand back up. And then run my skimmer air inlet to the outside

ReefMadScientist · Aug 24, 2015

anarchy said:
After reading I'll probably have to open my stand back up. And then run my skimmer air inlet to the outside

Glad you read it! Yeah I just ran my line up the wall, through the attic, and to an outside corner. My pH has been at a steady 8.0 since

anarchy · Aug 24, 2015

ReefMadScientist said:
Glad you read it! Yeah I just ran my line up the wall, through the attic, and to an outside corner. My pH has been at a steady 8.0 since

I may run mine to a near by basement window. They are small 6" x 12" windows with a screen. Adam @Battlecorals gave me a great idea about doing this. He runs his outside but before it gets to his skimmer it goes through a reactor that is filled with I believe filter floss and carbon, correct me if I'm wrong Adam, then it goes to the skimmer to prevent anything unwanted from ever reaching his system

ReefMadScientist · Aug 24, 2015

anarchy said:
I may run mine to a near by basement window. They are small 6" x 12" windows with a screen. Adam @Battlecorals gave me a great idea about doing this. He runs his outside but before it gets to his skimmer it goes through a reactor that is filled with I believe filter floss and carbon, correct me if I'm wrong Adam, then it goes to the skimmer to prevent anything unwanted from ever reaching his system

Yep. Tomorrow I get my CO2 scrubber in.

So I will be running it like this: Skimmer > CO2 Scrubber > Outside fresh air. (All connected by air line of course).

Anyway, here is what I will be running.

http://www.bulkreefsupply.com/brs-color-changing-medical-grade-co2-absorbent.html

http://www.bulkreefsupply.com/universal-air-filter.html

neuwave · Aug 24, 2015

I had PH issue a few years back. I've been using a CO2 scrubber for about 4 years now and have had great success. The heat and humidity can get pretty intense in Florida so the windows stay shut. At the moment the Ph has been at 8.2 in the morning and 8.3 before the lights go out. Before I installed it I always hovered around 7.8 at its peak during the day. I buy the bulk CO2 media(soda lime) in 5 gallon buckets which is about 37 lbs. It lasts a little over a year which puts me average of $8 or less a month. So I can't complain with the results.

Downbeach · Aug 24, 2015

If you can get outside air to your skimmer, its unlikely you'll need the CO2 scrubber media(soda lime can be expensive). I would however consider using some GAC to keep any contaminants from entering your skimmer from the outside, i.e. insecticides, etc. You can use the same device, connect it the same way, just get the proper GAC as the media. I would also suggest you put some kind of filter/screen on the end of the pipe/tube you're using so small critters don't get into it and block the air flow. I used an old prefilter from a Maxijet on the end of my 1/2" vynil tubing.

Randy Holmes-Farley · Aug 24, 2015

You can try this simple aeration test to see if the problem is primarily CO2 in your tank water only or also CO2 in your home air:

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com
from it:

The Aeration Test

Some of the possibilities listed above require some effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure the pH. Then aerate it for an hour with an airstone using outside air. The pH should rise if the pH is unusually low for the measured alkalinity, as in Figure 3 (if it does not rise, most likely one of the measurements (pH or alkalinity) is in error). Then repeat the same experiment on a new cup of water using inside air. If the pH rises there too, then the aquarium pH will rise with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise inside (or rises very little), then the inside air contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should).

anarchy · Aug 24, 2015

Randy Holmes-Farley said:
You can try this simple aeration test to see if the problem is primarily CO2 in your tank water only or also CO2 in your home air:

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com
from it:

The Aeration Test

Some of the possibilities listed above require some effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure the pH. Then aerate it for an hour with an airstone using outside air. The pH should rise if the pH is unusually low for the measured alkalinity, as in Figure 3 (if it does not rise, most likely one of the measurements (pH or alkalinity) is in error). Then repeat the same experiment on a new cup of water using inside air. If the pH rises there too, then the aquarium pH will rise with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise inside (or rises very little), then the inside air contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should).

Thanks for the reply I'll do the aeration test. I was wondering since my cal reactor (currently running without co2) is always higher than my tank ph, if I add aragonite sand to my tank if it will help buffer the pH

Randy Holmes-Farley · Aug 24, 2015

anarchy said:
Thanks for the reply I'll do the aeration test. I was wondering since my cal reactor (currently running without co2) is always higher than my tank ph, if I add aragonite sand to my tank if it will help buffer the pH

No. Aragonite won't dissolve in seawater unless the pH is well below 7.8. What you are seeing is likely a calibration difference.

anarchy · Aug 24, 2015

Randy Holmes-Farley said:
No. Aragonite won't dissolve in seawater unless the pH is well below 7.8. What you are seeing is likely a calibration difference.

I thought the aragonite kind of absorbs the excess co2

Randy Holmes-Farley · Aug 24, 2015

If the pH is low enough with excess CO2 (down into the mid 7's or lower), it will dissolve, but seawater at pH 8.2 is substantially supersaturated with calcium carbonate and it cannot dissolve. The exact pH where dissolution begins depends on alkalinity (higher alk means lower pH), but it won't be above pH 7.7.

anarchy · Aug 24, 2015

Randy Holmes-Farley said:
If the pH is low enough with excess CO2 (down into the mid 7's or lower), it will dissolve, but seawater at pH 8.2 is substantially supersaturated with calcium carbonate and it cannot dissolve. The exact pH where dissolution begins depends on alkalinity (higher alk means lower pH), but it won't be above pH 7.7.

Thanks I'll swap out the probes and see if they are still reading different values