pH - is 7.2 too low?

[nanojg]

Originally Posted by Inexplicable

All I have is the API kit and the Salifert kit, neither expired. My LFS doesn't carry any others. I can order a different kit if you have a better one to suggest?

Have you tested the saltwater planted tanks alk, maybe compare that to the reef tank.

[jdegrasse]

This is a mystery to me. I agree with Randy for sure, but I also think you've done enough testing with different kits/meters under different conditions and on different tanks to believe the pH and Alk values.

How could CO2 affect this one tank but not the others? Hmmm.... You sure you don't have a soda bottling machine right next to it? Or your skimmer is hooked up to a CO2 tank?

Hopefully this is just an odd occurrence and it goes away after several water changes.

Good luck.

[chuckreef]

What if the question (quoted below) is re-stated as:
Could there be something in this tank's water that chemically interferes with the dye-indicators used in the test kits?

[QUOTE=... Could there be another dissolved ion in the water causing a low pH besides CO2? Some sort of confounding factor only with my reef? [/QUOTE]

[m2434]

Is there a skimmer on your reef tank and no skimmer on the other tank? Or an open top on the reef and closed top on the other? Basically any reason you would have more aeration on the reef than other tank?

The reason I ask is maybe the extra aeration is saturating the water with CO2. On the other hand, the other tank, if there is less gas exchange, maybe is not CO2 saturated. This scenario is actually possible.

Another option is the planted tank is consuming a large portion of CO2. This also seems very likely. Could be a combination as well.

[Inexplicable]

Originally Posted by m2434

Is there a skimmer on your reef tank and no skimmer on the other tank? Or an open top on the reef and closed top on the other? Basically any reason you would have more aeration on the reef than other tank?

Good question. I hadn't thought of it this way, but the planted tank is skimmerless, so it is probably getting less aeration. It has a small air pump, but not near the aeration I am getting with my skimmer in the reef. My FOWLR is also skimmerless, so the same issue applies.

The reef has an open top with a fan to cool my LED heatsink and provide surface gas exchange. My suspicion is that you are correct, and the increased aeration of my CO2 saturated home is dropping the pH of my reef.

Update: I re-tested the pH of my reef after having all my windows open all day, and I am now at a pH of 7.8. I now am higher than I have been in a couple of months, so I'm pretty sure I'm on the right track. Perhaps with a couple of water changes and more air intake from outside I will be alright. I will probably start dripping kalk at night as well to prevent huge swings in pH. Thanks for all your help guys.

[Randy Holmes-Farley]

How could CO2 affect this one tank but not the others?

The relationship is different in fresh water, and if the new RC is not fully aerated with high CO2 home air, then the pH will not drop from where it initially mixes to.

[Randy Holmes-Farley]

I re-tested the pH of my reef after having all my windows open all day, and I am now at a pH of 7.8. I now am higher than I have been in a couple of months, so I'm pretty sure I'm on the right track. Perhaps with a couple of water changes and more air intake from outside I will be alright.

I certainly believe pH 7.8 is likely.

Water changes are not usually useful for solving pH problems, but are certainly not a problem to do them.

FWIW, I think planted tanks often run CO2 deficient, hence the addition of CO2 in such tanks.

[m2434]

Originally Posted by Randy Holmes-Farley

How could CO2 affect this one tank but not the others?

The relationship is different in fresh water, and if the new RC is not fully aerated with high CO2 home air, then the pH will not drop from where it initially mixes to.

Originally Posted by Inexplicable

saltwater planted tank

[m2434]

Originally Posted by Inexplicable

Good question. I hadn't thought of it this way, but the planted tank is skimmerless, so it is probably getting less aeration. It has a small air pump, but not near the aeration I am getting with my skimmer in the reef. My FOWLR is also skimmerless, so the same issue applies.

The reef has an open top with a fan to cool my LED heatsink and provide surface gas exchange. My suspicion is that you are correct, and the increased aeration of my CO2 saturated home is dropping the pH of my reef.

Update: I re-tested the pH of my reef after having all my windows open all day, and I am now at a pH of 7.8. I now am higher than I have been in a couple of months, so I'm pretty sure I'm on the right track. Perhaps with a couple of water changes and more air intake from outside I will be alright. I will probably start dripping kalk at night as well to prevent huge swings in pH. Thanks for all your help guys.

Right, Co2 will enter the water quickly, but less quickly if there is less air exchange. In the meantime, the plants are probably consuming the CO2 in the tank. So, I think it's likely the combination. I think kalk and maybe a CO2 scrubbing system, if still too low after the kalk, should help the reef.

[backettrio]

What if we aerate the water outside when we are reading high ph as above 8.5? Is it going to decrease?

[Randy Holmes-Farley]

Depends on the alkalinity, but yes, aerating inside or outside will lower pH when the pH in the water is higher than it should be based on the alkalinity and CO2 level in the air.

I show that there:

High pH: Causes and Cures
http://reefkeeping.com/issues/2005-03/rhf/index.htm

from it:



Figure 5. The effect of aeration on alkalinity and pH.

[DustinB]

Originally Posted by Randy Holmes-Farley

How could CO2 affect this one tank but not the others?

The relationship is different in fresh water, and if the new RC is not fully aerated with high CO2 home air, then the pH will not drop from where it initially mixes to.

Randy, I believe his planted tank is saltwater too. Do you think it would be advisable for him to run his skimmer intake outside with a sponge filter? I have of some people doing this to maintain a better pH level.

[Randy Holmes-Farley]

Yes, that can help.

[Inexplicable]

Originally Posted by DustinB

Do you think it would be advisable for him to run his skimmer intake outside with a sponge filter? I have of some people doing this to maintain a better pH level.

I actually did this late last night. I plumbed my skimmer intake to a jar with two holes in the lid, and filled the jar with filter floss (just to filter out particulate). The other hole I fed with an air pump drawing in fresh air from outside. This morning I checked the pH of the tank and found it to be 8.1. So it seems like my problem was purely CO2 related. I also bumped up my alkalinity to 10 dKH slowly overnight. My only suggestion to those with similar problems is to make changes slowly. I may have done it a little fast as I am seeing STN on one of my acropora colonies since making these changes.

[Randy Holmes-Farley]

Sounds good.

Happy Reefing.

[GlenG]

Is your low ph tank in your bedroom? I logged CO2 levels in my bedroom and living room over several days. The living room stayed around 450ppm 24/7 while my bedroom at night with the windows closed increased over 1600ppm.

[Randy Holmes-Farley]

while my bedroom at night with the windows closed increased over 1600ppm.

Probably helps you sleep soundly.

[GlenG]

Im surprised im not dead.

[HighlandReefer]

If you have a ventless fireplace this will drive up the CO2 levels in your tank quite a bit. Faulty gas and oil heathers that are not exhausting properly can do this as well.

[sdblanshan]

I have read that lava rock can lower ph in some cases, do you have any lava rock in your water? I am fighting the same problem... Its beyond me...

[Spyderturbo007]

I'm hoping he solved his problem, since this post is from 2011.

[Psxerholic]

Inexplicable,

Did this resolve your issue?
Please respond, i have a similar issue and have done all kind of stuff and think my water is contaminated but will do the aeration measurements as well today to see.
My ph is dropping down to 7.4 at an Alk of 8-10.

I could no believe that co2 can be so high in the house to drop the ph that low.

PSX

[Reefers4U]

Originally Posted by Psxerholic

Inexplicable,

Did this resolve your issue?
Please respond, i have a similar issue and have done all kind of stuff and think my water is contaminated but will do the aeration measurements as well today to see.
My ph is dropping down to 7.4 at an Alk of 8-10.

I could no believe that co2 can be so high in the house to drop the ph that low.

PSX

its happening to me right now. although my pH never got that low - somehow CO2 is getting into my tank. What worked for me was a running my skimmer air intake outside - be sure to get a diameter that fits over your current tube, not in it. And a fan to exchange the air in the house via a window next to the tank.

If you make your own salt I've heard it can also come from the tap water - maybe worth it to test for C02.

HTH

[Psxerholic]

All right guys,
this thread resolved my issue.
In the past I even ran down to 7.2 but mostly 7.5 or so.

I did the aeration test today, thanks to this simple and genius method to detect if Co2 in the room affect the reef tank!
Took the water from the tank and aerated it within the room.
The result was, it dropped to 7.6 then I interrupted the aeration and brought the jar outside and aerated it for around 5-6 hours.

Then the Water PH in the jar went up to 7.91. Great!!!!
So I brought this jar back into the house and kept aerating it.
It dropped again just within 45 minutes down to 7.71.

So I ordered the Co2 Absorber and a RODI cartridge at THE FILTERGUYZ.
This will be connected to the Air inlet of the Skimmer.

Theoretically, the Co2 reduced Air will positively increase the PH just because there is no new Co2 introduced, and as well the aeration of Co2 free air will get the existing Co2 out of the water. Since the Durso's and Water surface is helping the Co2 gettting into the tank as well.

I will post the results to see how effective this is gonna be.

Happy Reefing
PSX