Re: O2 pearls from plant stem breaks

Paul Krombholz wrote:
> Plants do really produce O2 when photosynthesizing,...  Aquatic
> plants have an interconnected system of air spaces that runs through the
> leaves, stems and roots.  When photosynthesizing actively, the O2 produced
> is added to the air spaces, and the pressure goes up until the gas starts
> escaping from some break in a leaf, stem, or root.  

I have seen air bubbles rapidly forming from four spots on a cut stem
of Bacopa. The spots were precisely symmetrical in location and I have
no doubt that these bubbles were streaming from the air transpiration
tubes of the plant. There was such a large quantity of bubbles that 
there must be a considerable amount of air present in the roots and
stems of the plants. Next time y'all trim plants, take a close look at
the cut stems; you can see the air channels with your naked eye
particularly on thick stemmed plants.

Matt Van Buskirk wrote:
> Subject: substrate question
> I am currently suffering substrate problems.  I have come to find out 
> that my $20 a bag gravel is causing my pH to raise to 7.6 and 
> stay there.  Even my co2 tank is doing little to lower it.  What evil 
> chemistry principal is at work here, and how do I combat it.  I seem 
> to believe my only option is to remove my $100 dollar investment and 
> pave my driveway with it!

Have you considered Tanganyikan Cichlids Matt? ;-) Seriously though,
your gravel probably has a large quantity of crushed sea shells 
(calcium carbonates) Try putting some of it in a jar of distilled 
water and measure the pH or carbonate hardness if you have a test 
kit for it in order to confirm this. Perhaps one of our chemistry
experts can suggest a good test. I don't think there is a suitable
remedy without removing the gravel; you'll have to live with that
pH and hardness. Probably not ideal depending upon your intended

If you purchased this from a pet store retailer sold as gravel
suitable for a fresh water aquarium, then you probably have a good
chance of getting a refund if you explain the situation to the
retailer; after all, your business and his reputation is worth a lot
more to him. He may want to return his gravel supplies to his
unscrupulous supplier too. If you used gravel intended for a salt
water aquarium, well, you shouldn't do that and can't really fault
the retailer.

Steve Pushak       spush at hcsd_hac.com            Vancouver, BC