CO2/PH for a discus tank - The Planted Tank Forum
LinkBack Thread Tools Display Modes
post #1 of 6 (permalink) Old 04-10-2006, 08:43 AM Thread Starter
PTrader: (0/0%)
Join Date: Apr 2006
Posts: 8
Question CO2/PH for a discus tank

First off thanks to those whom were kind enough to answer a newbies basic questions on setting up a planted discus tank.

Basic question again.

Here in SE Michigan we have a PH a touch alky. 7.3-7.6. Many local discus breeders (Great Lakes Discus for instance) have good luck in keeping and breeding in water right from the tap.

In a tank that uses CO2 for plants. The addition of the CO2 will cause the PH to drop, right ? As the controllers I have seen all use PH as the means of measuring the CO2 delivery.

So then how do we control the addition of CO2 in an amount benefical to the plants without changing the water chemistry ?

Also taking into consideration the water used for WC`s.

It would seem that the discus would be swimming in a constantly changing enviroment with the inculsion of CO2, WC`s and the parameters within the tank itself.

Could someone help me to understand this or provide a link to explain ?

John Edwards is offline  
Sponsored Links
post #2 of 6 (permalink) Old 04-10-2006, 10:27 AM
Algae Grower
PTrader: (1/100%)
Join Date: Apr 2005
Location: Los Angeles, California
Posts: 73
PH changes due to CO2 don't effect the fish as far as I have seen. It's when the PH crashes due to low alkalinity where you start running into problems. So there shouldn't be any problems as long as everything else is stable, even touchy discus.
Wiggawam is offline  
post #3 of 6 (permalink) Old 04-10-2006, 12:43 PM
PTrader: (28/100%)
Join Date: Jul 2005
Posts: 1,984
As the controllers I have seen all use PH as the means of measuring the CO2 delivery.
I think this is your answer. By using a pH controller such as the Milwaukee MA957+SMS122, the pH shouldn't fluctuate more than 0.1-0.2 points.

As for water changes . . . . . . I don't know about you, but most of my fish really enjoy a new batch of water. But . . . .. they aren't discus! I think most/many discus keepers allow their water to age and bring it up to temp before they use it. I guess another way to reduce the stress during pwc's is to introduce the new water very slowly.

But then again, I've read over and over that smaller but more frequent (daily) water changes are best for discus. Maybe partially for this reason!
esarkipato is offline  
post #4 of 6 (permalink) Old 04-10-2006, 04:10 PM
PTrader: (1/100%)
Join Date: Apr 2006
Posts: 129
I keep discus in a planted tank. Unless you're keeping wild caught fish, discus will do just fine at higher pHs. Now, if you use a Milwaukee controller, like already mentioned, you will be able to nicely control your pH where you want it. My pH is 8.0 out of the tap. My discus haven't had any issues with it. Of course, mine are young. Breeding discus may require a lower pH (there's still debate on this).

I put my discus in my planted tank, they are now at a pH of 6.8. I've not seen any problems at all with them. They are thriving and growing like weeds.

I don't bother aging my water, either. I make sure the temp out of the tap is correct and put the water directly in (I'm on a well, so I don't have to worry about city water issues). I change water twice a week, about 25%.

The discus strains developed are a far cry from their wild counterparts, just like with most fish. Strains carrying pigeon blood are also particularly hardy. There are some strains that are known for being fragile...the ghosts, in particular.
Titania is offline  
post #5 of 6 (permalink) Old 04-10-2006, 04:36 PM
Planted Tank Guru
Georgiadawgger's Avatar
PTrader: (16/100%)
Join Date: Apr 2004
Location: Kansas City, MO
Posts: 2,423

Keeping discus isn't really that difficult, other than a couple more water changes than usual per week and feeding them a lot of messy food!

I used to age my tap water (24 hours) before swapping it out, but now I'm just filling directly from the tap...generally my pH is 7.2 from the tap and with co2 its around 6.3. No issues with the drastic change in pH during the water changes.

Just give the fish some time to acclimate to the procedure...mine usually hover around the fresh water and greet the oncoming rush (they seem to play in it)...and they're also used to getting blood worms during water changes. Normally I have to shoo them away with my python to clean the gravel and move/trim plants.

Patience will be the key

Georgiadawgger is offline  
post #6 of 6 (permalink) Old 04-11-2006, 03:57 AM
Planted Tank Guru
plantbrain's Avatar
PTrader: (267/100%)
Join Date: Dec 2003
Location: The swamp
Posts: 13,609
pH can change for a number of reasons, but CO2 induce pH changes play no role, I repeat and I will likely repeat this 10,000 more times, no role in providing a "better" stable place for any fish, let alone discus.

Now changing the salt content and raising the KH up rapidly is something totally different and can kill fish.

But pH has a number of things that can cause it to move,.

A pH controller offers nothig better for your fish vs on durin gthe day and off at night.

I'd argue that leaving high levels of CO2 on 24/7 and chronically high CO2 is much worst than the pH effects from not adding it at night.

Fish do not need CO2 at night, nor do bacteria, nor plants, so why add it?
The only good reason I've heard is: it's simpler for folks that add CO2 into their filters.

But using a solenoid/air stone works, or a powerhead that are connected to the light timer.

That's simple to do and it allows you to add more CO2 when you need it and then only when the plants are also adding higher levels of O2.

If you honestly believe that the pH changes causes fish stress/worst etc, then you better never do water changes either in a CO2 enriched tank...........without adding the same amount of CO2 directly to the replacement water, which no one ever does.............

We do 50-75% even water changes in CO2 planted tanks with plain old tap without issues and folks have for the last 20 years of CO2 injection usage.

Never bothered fish before. The tap's pH is dramatically different than a CO2 enriched tank. I've bred Discus in my planted tanks in the past. They did not care about pH either.

Tom Barr

Tom Barr
plantbrain is offline  


Quick Reply

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome