how to keep CO2, PH, and KH in balance

loaches r cool

loaches r cool

Snail Terminator
Feb 15, 2006
1,830
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Gahanna, Ohio
tristan.homelinux.net
Hello all, this will be my first post here. I came here because I am pulling my hair out trying to keep my tank 'in spec'. Its my 75g planted tank that I setup about 1 yr ago. I have most all the test kits and used to take readings every so often. It has been a while since I took any. I just took some the other day and they seemed kinda outa wack. I did about a 30-40% water change and retested today. Thought I would post this and hopefully maybe someone can give me some advice?

PH=6.4-6.5, KH=~1, CO2=well I gave up after 60ppm because I didnt want to waste my whole test bottle.

This just seems really odd to me. How can the CO2 be so high? I inject about 1 bubble per 3-4 seconds, using a glass diffuser that is currently clogged, but CO2 is bubling out were the hose attaches to it in pretty fine bubbles so I havent fixed it yet. Injection runs 24x7 but when the lights go out a powerhead near the surface kicks on that agitates the surface plus bubbles air into its output. I would like to get the conditions back to ideal because I plan on adding several more plants and a few more fish by the end of the month. :help:

Tristan
 
loaches r cool said:
Hello all, this will be my first post here. I came here because I am pulling my hair out trying to keep my tank 'in spec'. Its my 75g planted tank that I setup about 1 yr ago. I have most all the test kits and used to take readings every so often. It has been a while since I took any. I just took some the other day and they seemed kinda outa wack. I did about a 30-40% water change and retested today. Thought I would post this and hopefully maybe someone can give me some advice?

PH=6.4-6.5, KH=~1, CO2=well I gave up after 60ppm because I didnt want to waste my whole test bottle.

This just seems really odd to me. How can the CO2 be so high? I inject about 1 bubble per 3-4 seconds, using a glass diffuser that is currently clogged, but CO2 is bubling out were the hose attaches to it in pretty fine bubbles so I havent fixed it yet. Injection runs 24x7 but when the lights go out a powerhead near the surface kicks on that agitates the surface plus bubbles air into its output. I would like to get the conditions back to ideal because I plan on adding several more plants and a few more fish by the end of the month. :help:

Tristan
Click to expand...
I presume your KH is degrees no ppm -- a KH of 1 is pretty low -- I would stop the CO2 and raise the KH to 4,5 or 6 range -- then start the CO2 again. A KH of 4 to 6 will buffer your PH and keep it from swinging to wildly.

How are you measuring CO2? If you have not added acid or base you should be able to estimate the CO2 from the PH and KH values -- I get 11 or 11ppm for KH=1 and PH=6.4. You will want a higher CO2 than that, I aim for KH=6 and PH=6.8 giving me about 25 to 30ppm CO2. The rule of thumb is to not add CO2 unless your KH is at least 4.
 
Just to clarify...my KH is around 1 degree... I am using the Aquarium Pharmaceuticals test kit and I put 1 drop in and the color slowly turned to the finished color. For the CO2 levels I have the Red Sea Plant Lab kit.

I figured I would need to raise the KH and I have searched old posts for a while and so far cant seem to find one post indicating how to do this.

"I would stop the CO2 and raise the KH to 4,5 or 6 range -- then start the CO2 again. "

I wasnt sure if shutting of the CO2 would hurt things since it has run constant for months... Its late tonight but if you think I should shut it off I might do it in the morning... Thanks for the help so far!
 
You can use baking soda to raise your KH. 1 teaspoon per 50 liters will raise your KH 4 degrees. Or add a piece of coral which will dssolve faster with a lower ph.

You CO2 levels are high. But sounds like an unlikely level due to aeration and other factors you stated. It's likely your test kits are failing you and giving you the wrong data. Take your water to a fish store and have them test it against your results.

-John N.
 
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loaches r cool, grab some crushed coral from any LFS (they will give a handful for free) and add a tablespoon in a nylon stocking and throw it in your filter.

As someone else mentioned, add baking soda to immediately buffer your water. The crushed coral works wonders and dissolves faster when the pH is low, so if the pH drops again, the crushed coral will do its job. The tap water in Columbus is close to 7.5 and with the right buffer, your tank should be in the 7.2 to 7.5 range
 
I added quite a bit of crushed coral to my filter. It hasn't done a thing in about 1.5 weeks (maybe I need to wait longer?). I've been told that adding baking soda on water changes shouldn't be to hard to do and that when you do water changes you are taking out whatever the coral put in the water anyway so might as well dose the baking soda.... Seems to make sense. But that is not what I always hear on this board. So I don't know who is right.
 
hurricanejedi said:
I added quite a bit of crushed coral to my filter. It hasn't done a thing in about 1.5 weeks (maybe I need to wait longer?).
Click to expand...

Remember., coral works very slowly when compared to Baking Soda....BUT...coral dissolves a lot faster when your pH is low and gives you the protection when you actually need it. Think of it as an insurance policy.

As far as taking it out with water change...I dont know, cichlid folks would have a hell of a time maintaining the high pH if the coral's buffer was lost after every water change :huh:
 
Definitely get your KH to a safer level. Coral is good. Aragonite works faster. Baking soda is instant so be careful not to add too much in one go.

I would suggest switching CO2 off until your KH is at 3 degress or higher because your tank is a candidate for a pH crash.
 
Baking soda, crushed coral, now we are getting somewhere. I guess I heard about baking soda once before but thought that couldnt be right lol. How quickly can you raise the KH with baking soda? WIll raising it a few degrees at once stress the fish? I'll try to raise it one degree right now and then wait for word here. I measured my tap water its comming it a 7.0 on the money if my test is accurate...btw I actually live in gahanna, I think the water is seperate from columbus. Cool to see someone else local though. I might supliment with coral also, but not sure about getting freebees, most places around here are big chain places and I never expected to get freebees before but I can ask.
 
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