pH chronically low

[Vesian]

Okay, so I know there are countless pH-related threads already on this forum. However, the pH level of my tank doesn't fit into the "my pH is low at 8.0, what should I do?" bunch.

 

For months now it is literally impossible for me to get my pH up to a safe level. Typically, I can raise it via several different methods to ~8.0 ish, and the it will drop again to about 7.5 during the night and 7.7 to 7.8 at the very end of the photoperiod. Here is the week's pH readings to demonstrate:

 

(Note that the extreme drop recently was when I recalibrated the pH probe)

 

I'm grasping at straws here. I've done everything that's been listed as common sense to get perfect water, and the pH still refuses to approach a safe level. A bit about my tank:

 

28g JBJ LED

 

Day Lights: On from 2pm-10pm

Dusk/Dawn Lights: On from 1pm-11pm

Night Lights: On from 10:30pm-1:30pm

 

Refugium in the middle chamber inside the media basket with Chaeto, using a JBJ LED refigium light to light it. Currently on a reverse photoperiod from 12am-12pm.

 

Salt: Using Tropic Marin Reef Pro Salt

Water: Using a SpectraPure MaxPure RO/DI unit

 

Skimmer: AquaC Remora

 

Temperature kept at a consistent 78.5f by a chiller

 

No additives or dosing.

 

 

Things i've thus far done to try to help the issue:

• I've tried frequent large water changes. As you can see by the graph, the water quickly returns to the low level.
  
• I've tried recalibrating the pH probe, hoping that it was just giving me innacurate readings. After recalibrating it with the appropriate solutions, no change.
  
• I've tried adding Marine Buffer from Seachem. pH rises, but then falls again.
  
• I've directed the return flow straight up at the surface instead of only partially to increase water agitation. No change.
  

 

Seriously, what am I doing wrong? I haven't had much luck with invertibrates and i'm speculating it's due to the pH swings.

 

Anyone have any advice? Am I missing something stupidly simple?

[MarcG]

Do you test alkalinity? What are the results?

[M1A1]

Where is the tank located? How old is the house/apt/etc? You likely have excess CO2 in the air around the tank and that is depressing your pH.

 

My 75g system is in a basement and I see a very similar affect with a normal pH of around 7.8. I can aerate a cup of tank water upstairs or outside and get a pH of 8.0 to 8.2 depending on the season. Kalk dosing is the only way to consistently raise the pH.

[DBarsotti]

I used to have this same problem, I would have HUGE pH swings in my40g system. 8.4 in the day, to as low at 7.65 at night. I tried running my refugium on a reverse photo period and this seemed to help a little but i was looking for much more stable results. The system was being dosed in the mornings with b-ionic 2 part at the time to maintain ca and alk so what i did was buy some dosing pumps (drews dosing pumps from BRS, they have a very low flow) and hooked them into my aqua controller. Since the pH swings only happened at night i programmed my controller to do almost all my 2part dosing throughout the night in small increments every 2 hours. This really seemed to help keep pH stable.

[M1A1]

Figure out the cause of the low pH first.

[Vesian]

Do you test alkalinity? What are the results?

 

I have not tested alkalinity; I was under the impression that regular water changes would replenish needed trace minerals (0 SPS in the tank, only current corals are 2 frogspawns, Ricordia, and numerous mushrooms)

 

 

Where is the tank located? How old is the house/apt/etc? You likely have excess CO2 in the air around the tank and that is depressing your pH.

 

My 75g system is in a basement and I see a very similar affect with a normal pH of around 7.8. I can aerate a cup of tank water upstairs or outside and get a pH of 8.0 to 8.2 depending on the season. Kalk dosing is the only way to consistently raise the pH.

 

The tank is located on the 2nd floor of a 1970's house in my room. The window is kept closed for the most part, although a hang-on air conditioner is sitting in it so the window is never completely closed. I do keep the door closed to my room; however, I have found that even keeping it open does not effect the pH readings.

[M1A1]

Can you aerate a glass of water outside your room for an hour and then check the pH? It does sound like you've tried enough things to eliminate high CO2 as the cause but it won't hurt to double check.

 

What controller do you have? I can't tell based on the screenshot. It seems you've ruled out everything except for a bad pH probe and a bad controller.

[7digits]

What kind of substrate? What kind of rock? Sounds like a buffering issue. Where is alk, calc, and mag?

[almost]

i read some where tropic marine pro is designed to have low ph/alc so you can run cal reactor/dose kalk, ect. try using tropic marine normal or redsea or instant ocean (tho i have low ph with instant ocean) when i buy natural seawater (the kind in jugs at fish stores and petco that cost way tooo much) my ph and alk balance out ..

[tako]

I've been dealing with a pH below 8 for the past several months as well. You really should test alk and calcium at the very least, also testing magnesium would be ideal. My alk had been hovering at 7 while my calcium had shot up to 540 by only doing weekly water changes. I'm now in the process of trying to get the calcium down and alk up.

[Steve-O21]

the salt you are using is meant for a reactor. If you are not using this it will be hard to maintain correct levels of alk, etc which will cause a low ph.

[shan]

Is your home heated by natural gas? If so, thats your problem. Natural gas puts CO2 into the air and that causes the level of CO2 to rise in your tank and drop the pH. I always run into the same problem each winter. Get an airpump and airstone and put the airpump outisde your window and run the stone into your tank. Or better yet if you have a skimmer run the airline outside your window. This will help dramatically and stabilize the pH. It may still average lower on cold days, but you probably wont see the bigger ph drops. Also do test your alkalinity. Higher alk will help keep your pH up.

[lakshwadeep]

This is a good overview of low pH and its causes and cures. Also, double check your calibrations with either a different pH probe/test or solutions. :

http://reefkeeping.com/issues/2004-09/rhf/index.php

[Genj]

I will put my money on your use of Tropic Marin Pro, which is designed for use with a Ca Reactor. Without you will have low PH.

 

I know this, because this is exactly the same salt I use, and i have to buffer constantly. Once I deplete my supply to the 20% remaining level, I'm switching to the standard Tropic Marin salt and mixing them together to transition myself out of the Pro salt.

[Vesian]

Is your home heated by natural gas? If so, thats your problem. Natural gas puts CO2 into the air and that causes the level of CO2 to rise in your tank and drop the pH. I always run into the same problem each winter. Get an airpump and airstone and put the airpump outisde your window and run the stone into your tank. Or better yet if you have a skimmer run the airline outside your window. This will help dramatically and stabilize the pH. It may still average lower on cold days, but you probably wont see the bigger ph drops. Also do test your alkalinity. Higher alk will help keep your pH up.

 

Lack of Oxygen in the air may be a potential cause of the problem, but i'm really hoping that's not the case. The tank is on the other side of the room and is about 20 feet away from the window. Not easy to run a tube the length to the tank. Also, AquaC Remora skimmers don't have an airline like typical skimmers do, so I unfortunately can't hook anything up to that.

 

 

This is a good overview of low pH and its causes and cures. Also, double check your calibrations with either a different pH probe/test or solutions. :

http://reefkeeping.com/issues/2004-09/rhf/index.php

 

Thanks for the link lak! I've read that article on numerous occasions, especially recently as this issue has become more and more of a sore thumb for me.

 

 

I will put my money on your use of Tropic Marin Pro, which is designed for use with a Ca Reactor. Without you will have low PH.

 

I know this, because this is exactly the same salt I use, and i have to buffer constantly. Once I deplete my supply to the 20% remaining level, I'm switching to the standard Tropic Marin salt and mixing them together to transition myself out of the Pro salt.

 

This is a really good point, and not something I had considered! I'll go out and purchase a different brand of salt and see if a few water changes helps remedy the problem! Thanks!

[markandstaci]

Air out the room. Changing CO2 concentrations in the air by a few PPM can have a significant effect on pH.

[gmckay]

I strongly recommend that you first test yor water ca/alk/mg before you try to correct your ph through dosing.

 

No harm in switching up your salt and aerating to see what may result.

 

 

Once you have a clear understanding of your water parameters, you can adjust accordingly via dosing if your levels are off.

 

Another point to address is your assumption that ph can be corrected by a partial water change. This is untrue, although your elements will replenish by the same percentage of your water change, there may still be an imbalance in the total water volume'

[HecticDialectics]

Is your tank actually SUFFERING from low pH?

[Vesian]

I strongly recommend that you first test yor water ca/alk/mg before you try to correct your ph through dosing.

 

No harm in switching up your salt and aerating to see what may result.

 

 

Once you have a clear understanding of your water parameters, you can adjust accordingly via dosing if your levels are off.

 

Another point to address is your assumption that ph can be corrected by a partial water change. This is untrue, although your elements will replenish by the same percentage of your water change, there may still be an imbalance in the total water volume'

 

Very good points, gmckay. I actually agree with you completely about the dosing. I tend to shy away from suppliments unless it's absolutely necessary, and beyond a few additions of the aforementioned pH buffer have not added anything to the tank.

 

I have been doing water changes for the last month at ~33% of total water volume. While the pH would rise immediately afterwards, it would gradually decline back to 7.5ish.

 

Is your tank actually SUFFERING from low pH?

 

That's a difficult question to answer. The tank has never completely thrived; there has always been something amiss (ie, snails dying, claim dying, etc). The mode i'm in right now is to try to fix conditions that are not CLOSE to accepted norms of the hobby. I think that's the best place to start. a Ph of 8.1-8.3 is widely accepted as the optimal range for our reefs. 7.8 is thrown around as not great, but still an okay reading. 7.5-7.6 is not okay, and it's something i'm seeking to correct.

 

 

Since my last post I went out and bought some new salt, Instant Ocean, and have done 2x 10g water changes on the tank. The pH readings are looking a little better now, and seem to be holding more steady over the night as well. This in contrast to 10g water changes using Tropic Marin Pro.

 

 

I appreciate everyone's input on this thread! It looks like it's helping me fix this :-)

[sean151]

I appreciate everyone's input on this thread! It looks like it's helping me fix this :-)

I think it's so cool and must be quite a relief to see it visually change over time after the water changes.

[Natural71]

Glanced at this thread and didn't see anything about your feeding schedule. How much and how often?

[HecticDialectics]

Good to see it moving in the right direction! Still going good?

[vangvace]

Perfect pH is a mythical beast that goes into hibernation in the winter months. lakshwadeep and HD have really given the best advice in the thread imo.

 

If your SG, Alk, Ca, and Mg are within established ranges and your inhabitants show no sign of stress then don't go chasing after pH. You can end up causing more harm than good.

[d9sccr]

I'm interested in what you find out with all this. I have a similar set up and have been doing the same things and not gotten any results. I'll post my pH readings later. Good luck

[FishStrings]

Air out the room. Changing CO2 concentrations in the air by a few PPM can have a significant effect on pH.

 

This helps too especially if you have your fish in a closed room. Keep the air in the room circulating as well. I live in Florida so I know how windy it is above that water.