Why would KH go down? - The Planted Tank Forum
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 12-13-2004, 07:07 AM Thread Starter
Planted Tank Enthusiast
motifone's Avatar
PTrader: (4/100%)
Join Date: Nov 2004
Location: Los Angeles, CA
Posts: 648
Why would KH go down?

ok, I'm a little confused --

When I set my tank up last week, I had a KH of about 5-6, with a pH of about 7.2-7.4. Today, after a week of pressurized CO2 injection controlled by a Milwaukee controller I'm getting a reading of 6.8 pH on the controller LCD and likewise a 6.8 pH reading from my Aquarium Pharmaceuticals test kit. So far, so good. (My tests kits use drops)

Then I went to test my KH with my Aquarium Pharmaceuticals KH kit (same one from earlier in week), and now my KH is reading is down to a 3.0 - low 4. Tested twice, same results. I also tested a sample of tap water: it was still a KH of 5 - 6 (just like when I first filled the tank).

What gives? I though KH was suppose to remain constant. No rocks, wood, or modifiers in my tank/filter. Just 100% Flourite. Some Water Sprite and Val and a few Angels.

At 6.8ph and 3KH I'm still providing a "good" level of CO2 (about 14ppm). BUT I was really hoping for the 20-25ppm of CO2 a KH of 5 would have provided me at 6.8ph. Any thoughts? Should I go lower to a pH of 6.6 or 6.7 (assuming KH stays at 3)? Is that dangerous? Not sure how folks usually go.

thanks as always
motifone is offline  
Sponsored Links
post #2 of 5 (permalink) Old 12-13-2004, 07:19 AM Thread Starter
Planted Tank Enthusiast
motifone's Avatar
PTrader: (4/100%)
Join Date: Nov 2004
Location: Los Angeles, CA
Posts: 648

After searching a little on here, I am suspecting it might be my Flourite.

I know, I know Flourite is not suppose to change water parameters like KH, but read this read, particularly the conclusions Rolo came to at the end:


I'm due for a water change soon, I'll see if that helps.
motifone is offline  
post #3 of 5 (permalink) Old 12-13-2004, 03:16 PM
Wannabe Guru
BSS's Avatar
PTrader: (12/100%)
Join Date: Sep 2004
Location: Oviedo, FL USA
Posts: 1,600
If the kh drops below 3, you can expect a pH crash, which could kill off lots of fish. I got lucky and didn't lose any. But, upon testing my pH one day, I noticed it at the lowest reading (6.0), so it could have been lower. Checking my kh, I found it was down less than 1 drop of reagent. I eventually tracked my kh (and gh!) killer to "toxic" driftwood. So, if the kh is continually dropping, either find the source or don't miss any weekly water changes.


46g bf, XP3 w/ vertical spray bar, CO2 w/ SMS122 & diffuser,100% Flourite, 96w+55w cf AHS, AGA Member
BSS is offline  
post #4 of 5 (permalink) Old 12-13-2004, 07:27 PM Thread Starter
Planted Tank Enthusiast
motifone's Avatar
PTrader: (4/100%)
Join Date: Nov 2004
Location: Los Angeles, CA
Posts: 648
sounds like I should do a water change tonight, since that was recommended for addressing possible Flourite problems
motifone is offline  
post #5 of 5 (permalink) Old 12-13-2004, 07:38 PM
Planted Tank Obsessed
PTrader: (0/0%)
Join Date: Aug 2004
Location: Alameda, CA
Posts: 492
Send a message via AIM to rayhwong
I read some where that the bacteria in the ammonia, nitrite, nitrate cycle will release acid as a by product. That could be the source of your KH drop.
Ive had a bare bottom tank that had dropping KH issues as well. The only cause of the drop would be the bacteria.


Eheim Pimp #91
Tank Information: 100 gallon TruVu, white play sand, Eheim 2028pro2 and 2026pro2, 2X96W PC 6700K and 2X55W PC GE 9325K, Pressurized CO2, Eheim autofeeder
rayhwong 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