Help with PH/KH/GH from tap - The Planted Tank Forum
LinkBack Thread Tools Display Modes
post #1 of 2 (permalink) Old 11-02-2015, 10:45 PM Thread Starter
PTrader: (0/0%)
Join Date: Apr 2014
Location: BC Canada
Posts: 4
Help with PH/KH/GH from tap

Recently moved to a new place and I'm going to be delving deeper into planted tanks. I decided to take some readings of my tap water and the results are as follows

PH: 6.6
GH: 2.24
KH: 1.12

I also have taken some readings from an established tank using this tap water with Fluval stratum and a medium sized piece of driftwood with some anubias tied on, and they are

PH: 6.4
GH: 3.36
KH: 0.56

Why is my KH so low and should I be adding anything to raise it? Is my GH at proper levels or should I be addressing this as well?

Sent from my iPhone using Tapatalk
mtlister is offline  
Sponsored Links
post #2 of 2 (permalink) Old 11-02-2015, 11:24 PM
Planted Tank Guru
PTrader: (0/0%)
Join Date: Jan 2010
Location: Contra Costa CA
Posts: 11,721
The substrate is probably removing the bicarbonates from the water, so the KH and pH are dropping.
You can correct this by adding baking soda (1 tsp per 30 US gallons = 2dKH) or potassium bicarbonate once or twice a week. Just enough to bump the KH back into the proper range.

Nitrifying bacteria and some other organisms use the inorganic sources of carbon (including carbonates) so I would keep the KH around 3 degrees. Also, monitor the pH. If that is still a bit low, go ahead and increase the KH a bit more.

GH ought to suit the fish. Most aquarium plants are fine with a wide range of GH. This supplies calcium and magnesium to both fish and plants. Seachem Equilibrium is one the the GH boosters that has a good ratio of Ca:Mg, plus some potassium. I would dose this when doing a water change, then monitor it through the week. If it drops more than about 1 degree between water changes, then I would add some each time you dose trace minerals.

Here is how I prepare new water for a water change:

1) Make the GH suit the fish.
2) Make the KH equal the GH.
3) This ought to make the pH in the right range for the fish. Fish generally are not as picky about the pH as people used to think. The important parameters are the mineral and salt levels. GH, KH and (if you have a meter, TDS).
4) If you are keeping black water fish, filter the water through peat moss to add the organic acids these fish seem to need. You could add oak leaves, alder cones, or any of several species of wood to the tank to do the same thing.
Diana 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