Must CO2 be used with 2 WPG ?

[NorCalAl]

OK, so does that mean with 2wpg we MUST use CO2? Or it's best that we do? I've read so much conflicting information that I'm in analysis paralysis here. I want to keep a planted tank, but I'm not sure I want to go the whole CO2 route. In my 65g, would I NEED a pressurized system or would one of the bubblers work? I realize most say that pressurized is NEEDED in a tank that large, but is that a fact or an opinion?
Trying to separate the two is often VERY hard! I want to do what's best, but I don't want to get so fanatical that it becomes a burden. I do water changes, but I don't do them every day. I test, too, but not every day. And in my 65g, which has around 20 plants, but will have more, I use florish, but is it enough?
Sigh, even with the internet and forums, it seems that you end up doing primarily trial and error.

 

[Purrbox]

2-2.5WPG is the grey area for CO2. Some tanks are fine without it, while others aren't. All tanks in this range will definately benefit from the addition of CO2.

Tanks that are 55 Gallons and larger are very difficult to get sufficiently high and consistant levels of CO2 using DIY CO2. You'll save yourself a lot of headaches by going with pressurized over DIY CO2. It also takes much less time for the expense of DIY CO2 to outpace pressurized in this size of a setup.

Once you get into higher light levels, you'll probably need to dose the following.
Flourish Comprehensive, Tropica Master Grow, or CSM+B (Micros)
Flourish Nitrogen or KNO3 (Nitrate)
Flourish Phosphorus or KH2PO4 (Phosphate)
Flourish Potassium or K2SO4 (Potassium)

It's fairly certain that you'll need to dose the Micros and Potassium while the Nitrate and Phophates will depend on your fish load, feeding routine, and tapwater contents. You'll probably need to test more upfront as you get a feel for your tank's nutrient needs, then later on only occationally to make sure things are on track or if you start to see a problem. A 50% water change once a week is recommended to replenish the trace nutrients that your plants need and aren't in the trace mix, as well as to reset the nutrient levels in your tank. Every day most certainly isn't necessary.

 

[noncentric]

I think that the higher wattage requires supplemental carbon, but I think you can use either CO2 injection OR Fluorish Excel with equal success.

The problem is that Excel has been reported to cause 'melting' in some plants - anacharis and ??? I think Excel would be a lot easier than CO2 if your plants are okay with it.

Good luck!

 

[NorCalAl]

So if I win the 192w I'm bidding on (on eBay), I guess I'm looking next to Co2, correct? If so, is there a comprehensive kit offered by someone to get me going? Or is it a piecemeal put it together yourself kinda thing?
Do the plant varieties have much to do with whether you add co2 or not? Or is it primarily a light-based equation?
Since the 65g is just my first, and I'm already contemplating a 180g that someone near me has for sale (cheap!!!), I guess I need to learn this no matter what.
One last, can I add the co2 into a sump (no, I don't have one on my 65g, but the 180 comes with one) and just have it pump from there into the tank?
Ah, the complexities.

 

[hashbaz]

It would be nice to get that ugly CO2 reactor out of the tank and into the sump. It will work fine there. How much surface agitation is there through the overflow?

There are comprehensive kits but they often do not include the CO2 tank. These are usually bought at the local welding-supply store to save on shipping. I bought my regulator and controller from aquariumplants.com (good price) and made my own reactor.

Adding CO2 seems to be more of a "light thing" rather than a "plant-variety thing."

 

[Purrbox]

You can order Pressurized CO2 kits that will contain everything except the CO2 cylinder which you will probably want to buy locally. The kits generally contain all the bells and whistles, so if you want more of a barebones setup you'll probably want to piecemeal it.

Essentials
CO2 Cylinder
Regulator with Needle Valve
Co2 Reactor
Tubing

Extras
Manifold (allows you to use a single setup with multiple tanks)
Selanoid Valve (allows you to turn the flow on and off electrically)
Timer or pH Controller (require Selanoid Valve)
Bubble Counter

If you're looking to save some money you could go with a barebones system and DIY CO2 Reactor. Here are some instructions for an inline reactor. There's also a few threads floating around the forum that have links to some very nicely priced systems. Might want to do a quick search to turn them up.

Light is usually the driving force behind going with CO2 or not. There are some plants that simply don't thrive without CO2. With High Light and no CO2 you are practically guarenteed to have algae, which generally is of more concern than a couple of plants that aren't doing much.

You should have no problem injecting CO2 into the sump. You'll just want to make sure to minimize surface agitation in both the main tank and sump.