Hi there, I am trying to find rocks for my aquarium from the canterbury region, does anybody know whether basalt rocks leech dangerous levels of iron into the water, or whether greywacke will remain stable and inert in the aquarium. These 2 types of rock are the most common around this area, Basalt from the mountains and greywhacke from the rivers.

Also does anybody have any information on modifying soda stream bottles for CO2 injection, ie: cost of refills, ease of modifying regulator valve, length of time between refills.

Cheers

Peet

I would not recommend basalt as it has very sharp edges and will damage the fish. A good alternative would be quartz which you will find in the Ashburton rivers and places like Mt Somers. Agate is also plentiful down your way.

Greywacke will be fine. It does not leech anything and does not have the sharp edges like basalt.

That information came from one of our members who is a member of the Rock & Mineral Club. There is not much about NZ rocks June doesn't know!

Can you use soda stream bottles for CO2 injection

[ This Message was edited by: peet on 2001-08-22 04:24 ]

Hi Peet

Sounds like a reasonable idea, to inject CO2

We havent used our Soda Stream for years, but the last time we had it filled, Well exchanged it was $5.00, This was enough to fill approx 50-60 bottles I think (It has been a while)

Cheers

Bruce

Thanks Bruce, I have pulled apart my soda stream, seems pretty simple to make up an adjustable valve, I need it for a tank of about 250-300litres, is this to big to use the inverted bell method like the Tetra CO2 dispensers or do I have to inject it into the filter (Have a Genio 700L/H cannister) in which case I will need to have a very fine valve to get down to the Bubble/sec range. Is there another way of perhaps dispensing the CO2 into a device that then regulates the no of bubbles into the tank or filter.

Peet

Hi Peet

This site should give you an idea of what you will need to get you going

Cheers

Bruce

http://www.hallman.org/plant/booth1.html

Hi Peet,

I use CO2 injection. I use a commercial 6.8kg Food Grade CO2 bottle that I rent from BOC Gases. The cost to rent it is about $95 per year, and gas refills about $25.00. It lasts about 2 Years. This bottle holds significantly more than a Soda-Stream bottle (probably at least 100x). It is also on a tank of 1200L. I do not use a gas reactor as they are a big waste of money. If you have a filter, inject the CO2 into its inlet if it can tolerate gas bubbles flowing through it, or into the return if it cannot. If you have to connect into the return, and some gas bubbles come out the end of the pipe, get a large diameter and longer return hose and fit it to the filter. You will need to zig-zag the hose vertically to maximise the turbulence in the hose. I use the return hose method and put about 6 bubbles (diameter 3mm - 5mm long) per second into the tank. This gives excellent growth on all plants. I use Barclaya longifolia as an indicator for too much CO2 as it develops holes in its leaves.

The beauty of using a commercial gas cylinder is it bolts straight up to standard CO2 regulators to take the 1000psi down to a managable 15psi. The regulator has stainless steel guts because CO2 is too corrosive for the standard brass type of regulator. Watch out for Sodastream regulators, they may not be up to the job long term.

[ This Message was edited by: Warren on 2002-01-24 19:19 ]

[ This Message was edited by: peet on 2001-08-22 04:22 ]