lowering co2 to raise ph

[tank a holic]

I saw this come up in another thread but I didn't want to hijack, so....
if dkh and calcium are on target, and ph is low is it safe to assume you have excess co2?
and if you have good flow, in what other way can you lower it?

 

[spanko]

Seems like this type of question comes up in the winter here and on other sites. As we close up our houses for the winter there can be an increase in CO2. A good way to check if this is what you are experiencing is to take some tank water, test the Ph and record the reading. Then put the water outside for a bit. Recheck and see if the Ph comes up. If it does it may be an air exchange thing going on in the house.

 

[beaslbob]

Originally Posted by tank a holic
http:///forum/post/3208397
I saw this come up in another thread but I didn't want to hijack, so....
if dkh and calcium are on target, and ph is low is it safe to assume you have excess co2?
and if you have good flow, in what other way can you lower it?

Depends on what you mean by low pH. PH like 8.2 or so can be more or less normal but if pH is down under 8 then IMHO it does signal potential problems. But even with that we had a local here who had been growing sps corals for years, selling frags and so on. His pH was 7.5 or so.
IMHO low pH always signifies high co2. The more serious question is how did it get there. In the example above the local dialed back the calcium reactor co2 and ph rose. Dripping kalk rasies pH.
But for a more normal, non calcium reactor, non kalk setup, The single best way to get pH up is by adding macro algaes. To me that simply trumps anything else. Especially, if the tank also had nitrates and phosphates. The macros raise pH by making the tank a net consumer of carbon dioxide and producer of oxygen every 24 hours. Plus they will also consume nitrates and phosphates.
My 55g had a pH of 7.6 or lower until I added macro algaes. In a week pH was above 8.4 (api test kit) and has stayed there for years.
also be sure to measure pH just before lights out and if high don't worry. That last thing you want to do is start making drastic changes for a low just before lights on pH value.
my .02

 

[drsteve2001]

ok to a newbie here what are macro algaes? so i can add them my ph is at 7.8

 

[jstdv8]

if you think its lack of o2 becuase your hosue is closed up tight. find a place where you can get a cup of your tank water some fresh air WITHOUT changing the temperature. put an airstone in the cup and let it run for an hour then take a new test. if the PH comes up that is indeed your problem.
Do you have good surface agitation in your tank?
Also adding a sump if its feasable will help get more O2 into the water too.
What is your alkalinity at?
If the areation doesnt work, try kalkwasser. Kalk will help remove excess CO2.
Make sure to follow the directions its not easy to add

 

[tank a holic]

there are 2 types of algae .... micro algae which is the thin film like or hair algae that grows on our rocks
and macro algae which is like caulpera and chateo which grow tall and have root systems
kinda like weeds
these are mostly used in sump's or refugiums to help in the filtering process

 

[beaslbob]

Originally Posted by drsteve2001
http:///forum/post/3208459
ok to a newbie here what are macro algaes? so i can add them my ph is at 7.8
Macro algaes are "ogranized" algaes that can look like plants.
the addition of macro algaes to your system will help raise your pH by consuming carbon dioxide and returning oxygen. Plus they also consume nitrates and phosphates as well and in the process suck out (filter) nasties like copper.
Fish and cleaner crews can and will eat them so usually some type of protected environment called a refugium is needed to seperate the fish/display area from the refugium/macro area. Even just an egg crate partition with some added lighting woud be sufficient.
So like FW plants macros complete the nitrogen cycle by consuming the end products. And in the process balance out and stabilize the operation of the aquarium.
my .02

 

[bang guy]

Originally Posted by tank a holic
http:///forum/post/3208397
if dkh and calcium are on target, and ph is low is it safe to assume you have excess co2?
It's safe to say it's most likely to be excess CO2, I wouldn't go so far as to assume that's the issue. It could also be a build up of metabolic acids from decaying organic material.
The test described above where you take a sample of water outside and retest is a sound diagnostic tool.
One caution with using Macroalgae to consume CO2 - it only works when the algae can photosynthesize (the algae must have light). When the algae is in the dark the reverse process occurs and the Macroalgae will produce CO2 instead of consuming it. This can be mitigated by having the algae in a seperate location connected to the display tank and lighting it opposite the display tank or 24/7.
Dripping Limewater will also consume CO2.

 

[tank a holic]

so dripping lime water will reduce c02
and not change your dkh... correct?

 

[bang guy]

Originally Posted by tank a holic
http:///forum/post/3209085
so dripping lime water will reduce c02
and not change your dkh... correct?
well... maybe I made a bad call there. If you know the dKH consumption rate of the system then you can tailor the limewater concentration to match the consumption rate. If you add more then you're right, dKH will rise.

 

[tank a holic]

thanks bang

 

[xcali1985]

if you dont have a sump for most macro algaes, you can put a few shaving bushs in your display tank, most of them look great especially in a reef tank. Im ordering 2-3 not and will install them in the sandbed right in the front corners of the tank. They do everything macro algae does except its actually a plant.

 

[tank a holic]

how do they look?

 

[bang guy]

Shaving Brush is a macroalgae. How well it does for nutrient export will of course rely on the quantity and growth rate of the algae.

 

[tank a holic]

so...
I tested water, ph 8.0, set a jug outside for an hour, stirred it every 10 min's
tested again, 8.0
so can i guess its not co2?

 

[natclanwy]

I wouldn't get to hung up about a Ph of 7.8 or 8.0, also have you tried testing your Ph several times throughout the day? You Ph will fluctuate quite a bit depending on the time of day, used to go from 7.8 to 8.3 depending on the time of day. Its far more important to have a consistent Ph than it is to have exactly 8.2 so as long as your Ph isn't dropping well below 7.8 and isn't rising above 8.4 I wouldn't worry about it as long as your Calcium, Magnesium and Alkalinity levels are good.

 

[tank a holic]

last nite was 8.0
this morning was 8.0, I'll check again this afternoon

 

[beaslbob]

The only pH measurement I take is just before lights out.
And also measure alk and keep that above 8 dkh by adding baking soda.
Guy is correct that macro algaes will release carbon dioxide and consume oxygen during lights out. But in my experience the tank will become a net consumer of carbon dioxide and producer of oxygen in a 24 hour period with plant life like macros balancing out the system. And under those conditions the just before lights out pH will reflect how completely the tank has consumed the carbon dioxide from the surrounding air and the much larger carbon dioxide from the fish. That to me is the important thing.
Adding baking soda to keep alk up will help limit the lights out pH drop. But again that actual pH drop is not what is important. Things like corraline algae and corals need the carbonate to grow. The limited pH drop is just a side effect. The main thing is to get the carbonate there for the life that needs it.
my .02