re: Bubbles during water change

---------- Forwarded message ----------
Date: Sat, 15 Feb 97 19:48:42 -0800
From: John <jlob at wpa_net>
To: aquatic-plants at actwin_com
Subject: Re:  Bubbles During Water Changes

> This very same bubbling occurs in all 3 of our plant tanks every time we
> do a water change - new water is 100% DI reconstituted and stored for 1
> - 3 days before use.


The same thing happnes in my tanks after a water change.  Does this 
happen to everyone?  It seems like it does. In the latest issue of FAMA a 
man said he has this happen to his tanks.  He tested his tap water and 
claims it is high in CO2 and its the CO2 from the tap water that causes 
this.  It was FAMA so I would take it with a grain of salt.  It would be 
nice to know what exactly causes this to happen.    

> Since our water mix is so soft, 3 GH & 3 KH, I thought that it might be
> calcium that was limiting so I started experimenting with adding small
> amounts of CaCO3 to 1 of the tanks with no change noted except a 1
> degree rise in KH - no change in GH or PH - which puzzles me as I
> thought that when adding CaC03 both KH & GH would rise equally?

Not sure.  I thought calcium carbonate would only raised the GH.  And 
bicarbonates would raise only the KH.  I read one thing in one book, one 
thing in another book, read a post here and read a post there, and get all 
confused.  :)  

> However I've also started adding PMDD for 1 week now to all 3 & just
> today in 1 of the 3 tanks (not the CaC03 test tank) the bubbling started
> like crazy just like it does after a water change - so I'm assuming its
> something in the PMDD, although I don't know which nutrient it is.

> Rebecca Marsh

Are there others using PMDD that experience this?  If so any ideas on what 
in PMDD would do this?  Is there ammonia in there?  Could ammonia do 
something like that?  I think most of us probably have ammonia in our tap 
water.  If it's possible maybe that would explain the bubbles from PMDD 
and water changes.