Hi.

I have two tanks. One is 30x15", the other 24x12". I would like to
have a CO2 system for both these, but don't want to spend a lot or use
gas cannisters. I also don't want to do the home brewing method
either.

What options are there to buy? I need something that I can see the
CO2 and PH levels, so I wont kill any fish I might get for the planted
tanks. Is there any device that can regulate the amount of CO2 to the
tanks that you can use and doesn't cost a lot?

I've seen the Hagen Nutrafin Natural Plant system, and also one by
Dupla. Does anyone have either of these and are they any good?

I have a Sodastream drinks maker, and just wondered what people though
to using this for adding CO2? You could make a few hundred
millimeters of water fizzy and add a bit to the water every so often?

I appreciate any recommendations. I am just getting back into the
hobby and haven't really done planted tanks in a major way, or
successfully before.

The CO2 is the last thing I need to look at, the lighting and
everything else is all prepared.

Thanks

John