how do you know you have enough co2?

[logan5]

When I fist started puting CO2 (a la DIY) I got some awesome plant growth with lots of bubbling ... now about three months later, I haven't changed anything I'm doing ... but i've notice a drop in growth and no more bubbling.

How do I test of CO2 content?  and should I start using ferts?  I haven't before and really don't want to.

Thanks
Logan5

[Mzungu]

Re: how do you know you have enough co2?

Quick question: Have you replaced the sugar/yeast solution, or is it still the same one you had three months ago?

[logan5]

Re: how do you know you have enough co2?

I use a two bottle system where I replace one each week and have had a steady stream of co2.

Logan5

[eklikewhoa]

Re: how do you know you have enough co2?

since the forum messed up and deleted a day ill post it again.

http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

how big is your tank? i have a 20H with a 2liter and 1liter running with almost perfect co2 levels for the tank and get excellent growth and occasional pearling.

[wesleydnunder]

Re: how do you know you have enough co2?

Chuck Gadd's chart can give you a rough idea of co2 concentration using KH and ph. As co2 increases, ph drops. Using Gadd's chart, you can see with your KH, what ph you need to get to your target CO2. It's not perfect though. It relies on KH being all carbonate and in this area we have other buffers, like phosphate, as components of our KH.

As your plant mass increases, the co2 is used up faster. It may be time to add another bottle.

Mark

[Mzungu]

Re: how do you know you have enough co2?

One more question, sorry. When you say "bubbling," do you mean the actual CO2 bubbles, or pearling?

[wesleydnunder]

Re: how do you know you have enough co2?

I went back and reread your first post. I missed where you said you don't fertilize. You may need to. Also, as I stated before, since you had three months of good growth your plant mass has increased and your plants use more CO2. Keeping it at around 24 ppm may require more bottles or an upgrade to pressurized.

Mark

[logan5]

Re: how do you know you have enough co2?

By bubbling I mean I can see CO2 bubbles coming into my reactor.  I guess I could start using ferts ... but like anything else there are so many on the market ... what's the best to use and how often?  When I use ferts, what's my indicators?  Nitrates and Phosphates?

Sigh ...

thanks
Logan5

[szidlon]

Re: how do you know you have enough co2?

If you're not seeing co2 bubbles in your reactor check for leaks.  After a while the cap on your bottle can get loose and not fit tight, there can be a small tear in the tubing or your check valve could have a leak.  It doesn't take but a pin head size leak to loose pressure.  I have been using the silicone tubing and haven't had a problem with the tubing, but I have had a cap go bad, a check valve start to leak co2 and had to reseal with silicone around the cap where the line goes in.  All the parts of my DIY system are so inexpensive or even free that I keep extra bottles, tubing, etc. around for just such problems.

[wesleydnunder]

Re: how do you know you have enough co2?

By bubbling I mean I can see CO2 bubbles coming into my reactor.  I guess I could start using ferts ... but like anything else there are so many on the market ... what's the best to use and how often?  When I use ferts, what's my indicators?  Nitrates and Phosphates?

Sigh ...

thanks
Logan5

Your macros are N,P,K. A freshwater master test kit has the nitrate test in it. I use a red sea phosphate test. I know of no test for K outside a lab. Here's what I use:

For nitrate - Mostly provided by my fish/filters - around 20 ppm, if I need to dose I use dry KNO3
For phosphate - My tapwater has 2 ppm PO4 already - if I need to dose I use Fleet Enema
For potassium - I use No-Salt from the spice section at the grocery store - it contains KCl

I try for NPK ratio to be 10:1:10. For trace elements I use fluorish, by seachem.

What is your lighting wpg? I find light to be the determining factor of how much CO2 and fert is needed.

Mark

[logan5]

Re: how do you know you have enough co2?

Right now my nitrates are pretty much zero ... I've actually prided myself in keeping my water pretty much clear of amonia, nitrite and nitrates ... but I guess I'm going to either have to cut back on water changes or start adding nitrates to the tank.

Logan5