Plants and their effects on Ph
Planted Tank Forums
Your Tanks Image Hosting *Tank Tracker * Plant Profiles Fish Profiles Planted Tank Guide Photo Gallery Articles

Go Back   The Planted Tank Forum > Specific Aspects of a Planted Tank > Fertilizers and Water Parameters


Reply
 
Thread Tools Display Modes
Old 05-14-2012, 05:07 PM   #1
jrman83
Wannabe Guru
 
PTrader: (12/100%)
Join Date: Nov 2010
Location: White Plains, MD
Posts: 1,000
Default

Plants and their effects on Ph


Does anyone experience ph changes with their planted tanks due to the plants - permanently? On another site I frequent there is one individual that swears his tanks all eventually get to a ph level of 8.2-8.4 and has had tap water that has started as low as 7.0 in the last 10yrs or so of moving around.

I have seen in my tanks a very slight difference at the end of a 10hr lighting cycle back before my tanks all had CO2, but it would be back to the previous level before the light would be coming on the next day. I assume this is the plants using up some of the CO2 in the water.

To give the full background on the individual, all of his tanks have no filters, no powerheads, and no water changes being done. He only replaces water as needed to topoff weekly. My belief is that his high ph is isolated to his stagnet water methods and not a normal plant action that he claims. His substrate is 1" peat, 1" sand, and 1" gravel. Although....one other person on the site now says they see some changes also.

Although there have been quite a few say they see no change as he does, curious to hear what you guys here have to say about it? What do you guys see in your tanks?
__________________
Eheim Pimp #448
jrman83 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-14-2012, 06:08 PM   #2
Hoppy
Planted Tank Guru
 
Hoppy's Avatar
 
PTrader: (74/100%)
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 18,666
Default

My money is on leaching of carbonates from his gravel, not the plants effect, if any, on pH.
__________________
Hoppy
Hoppy is offline   Reply With Quote
Old 05-14-2012, 06:12 PM   #3
jrman83
Wannabe Guru
 
PTrader: (12/100%)
Join Date: Nov 2010
Location: White Plains, MD
Posts: 1,000
Default

He claims that his plants use up all the available CO2 in his water, thus driving up the ph.
__________________
Eheim Pimp #448
jrman83 is offline   Reply With Quote
Old 05-14-2012, 06:25 PM   #4
HD Blazingwolf
Planted Tank Guru
 
HD Blazingwolf's Avatar
 
PTrader: (8/100%)
Join Date: May 2011
Location: Chattanooga, TN
Posts: 4,907
Default

c02 leaves the water on its own.. and it doesn't take long.. with any decent flow. c02 that's injected or is already present in the tap water will leave in abou 45 mintues to an hour
__________________
HD Blazingwolf is offline   Reply With Quote
Old 05-14-2012, 11:29 PM   #5
Hoppy
Planted Tank Guru
 
Hoppy's Avatar
 
PTrader: (74/100%)
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 18,666
Default

The water is also constantly absorbing CO2 from the air, so it is never at zero concentration. Both the loss of CO2 and the absorption of CO2 occur at the same time.
__________________
Hoppy
Hoppy is offline   Reply With Quote
Old 05-14-2012, 11:33 PM   #6
ThatGuyWithTheFish
perugiae
 
ThatGuyWithTheFish's Avatar
 
PTrader: (23/100%)
Join Date: Apr 2012
Location: Boston
Posts: 2,278
Default

Apparently tanks slowly become more acidic over the years. I'm not too sure why, that's just something I've heard from someone I'd trust.
__________________

"Boulders-Upon-Meadow"


My Golden Rule of planted tanks: WWTAD-
"What would Takashi Amano do?"


RAOK Club #69
ThatGuyWithTheFish is online now   Reply With Quote
Old 05-14-2012, 11:47 PM   #7
HD Blazingwolf
Planted Tank Guru
 
HD Blazingwolf's Avatar
 
PTrader: (8/100%)
Join Date: May 2011
Location: Chattanooga, TN
Posts: 4,907
Default

Over time the buildup of mulm can create more acidic water, if water changes are done properly. The continual balance of kh makes this negligable. Otherwise poor water change habits will make this happen rather quickly
__________________
HD Blazingwolf is offline   Reply With Quote
Old 05-15-2012, 05:18 AM   #8
mistergreen
No more Bow ties
 
mistergreen's Avatar
 
PTrader: (13/100%)
Join Date: Dec 2006
Location: Cincinnati
Posts: 13,896
Default

It had been observed in terrestrial plants that they actively drive down the ph in the soil to make certain minerals like iron available for use. I could see aquatics do that too.
mistergreen is online now   Reply With Quote
Old 05-15-2012, 10:47 AM   #9
HD Blazingwolf
Planted Tank Guru
 
HD Blazingwolf's Avatar
 
PTrader: (8/100%)
Join Date: May 2011
Location: Chattanooga, TN
Posts: 4,907
Default

Quote:
Originally Posted by mistergreen View Post
It had been observed in terrestrial plants that they actively drive down the ph in the soil to make certain minerals like iron available for use. I could see aquatics do that too.
Not that this isnt possible. But i have not seen this. I however have not tested the substrate to see if that happens there.
It may not be neccessary thought because mulm builds up in the substrate where it will release acid which would help absord nutrients.
The effect on water is not noticed under normal water change conditions
__________________
HD Blazingwolf is offline   Reply With Quote
Old 05-15-2012, 06:48 PM   #10
m8e
Planted Member
 
m8e's Avatar
 
PTrader: (0/0%)
Join Date: Oct 2009
Location: Sweden
Posts: 201
Default

There is a bunch of ways plants can lower the pH.
Plants take up more cations than anions and releasing H+ ions.
Plants actively releasing acids.
Plants using carbonates as a carbon source, softening the water. (For example egeria can do this)
Plants decomposing releasing CO2, tannins, acetic acid, humic acids etc.

Plant can rise the pH by using CO2...
m8e is offline   Reply With Quote
Old 05-15-2012, 08:39 PM   #11
iano7000
Algae Grower
 
PTrader: (0/0%)
Join Date: Apr 2012
Location: Vancouver, Canada
Posts: 65
Default

You explained it in your original description. This individual isn't doing water changes, only topping off the water. Follow this example,

Week one, PH is 7.
Water evaporates, therefore calcium and magnesium concentrations go up.
Say after this water evaporation PH is now 7.1.

Week two, PH is 7.1, and he tops up the water. The top up water is diluting the PH7.1 water with PH7. So now his PH is 7.05.
Again water evaporates, but calcium and magnesium still stay behind. His PH is now 7.15.

Through this same process, after week three, his PH is 7.2, then 7.25 etc.

It makes sense that he would end up with a high PH using this logic. Its the same reason so many of us use the 'reset' day with EI dosing. It's so the concentrations don't get so high.


The logic of plants causing water to become basic is nonsense. If a tank starts with PH7, and after injecting CO2, the PH drops to 6. It wont return to PH8 after all the CO2 gets used up by way of the plants or natural dissipation.

Hoppy makes a strong possibility as well, with the idea of substrate leaching.
iano7000 is offline   Reply With Quote
Old 05-15-2012, 09:16 PM   #12
takadi
Planted Tank Obsessed
 
PTrader: (0/0%)
Join Date: Dec 2010
Location: Northern VA, USA
Posts: 496
Default

My tank becomes extremely acidic when I top off, it's kind of weird.
takadi is offline   Reply With Quote
Old 05-16-2012, 06:08 PM   #13
jrman83
Wannabe Guru
 
PTrader: (12/100%)
Join Date: Nov 2010
Location: White Plains, MD
Posts: 1,000
Default

Nice to read the different responses. Based on what has been posted, I glean from that most believe that plants don't cause huge changes and if they cause any change it is usually only a slight difference, and that if it were sustained for any period would be "reset" by a water change.
__________________
Eheim Pimp #448
jrman83 is offline   Reply With Quote
Old 05-17-2012, 02:06 AM   #14
Diana
Planted Tank Guru
 
PTrader: (0/0%)
Join Date: Jan 2010
Location: Contra Costa CA
Posts: 6,967
Default

I have heard of that method as described in post #1, and I disagree with his conclusion (There may be more than one person doing this method... but I think I know who you are talking about).
I think it is the accumulation of minerals (especially carbonates) because of topping off with tap water that is driving the pH up.

I see the same thing in my tanks in the summer. In the winter I top off with rain water, and do water changes with tap water. In the summer there is no rain, so I top off with tap water. TDS goes up over the summer, in inverse proportion to how many big water changes I do. When I do lots of water changes the TDS stays stable. The more topping off I do the more build up there is in the water.

Ditto m8e: There are many things that life does that lowers the pH. In addition to plants, microorganisms and animals also contribute to lowering the pH. In nature there is usually a balance, or else changes happen slowly, but look at how many soft water habitats there are, from rain forests to peat bogs. The hard water habitats are areas where more minerals are added to the water, such as the Rift Lakes, and waters in areas with high calcium and magnesium carbonate soils. Karst regions, for example.

While there sure might be minerals leaching from the gravel in those set ups, there is also peat moss blended in there. I know that peat moss can act like an ion-exchange water softener, but it eventually gets used up, I would think.
Diana is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 06:34 AM.


Powered by vBulletin®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright Planted Tank LLC 2012