?'s re ferts/co2 for new 20L

[dcewing]

This is my 1st post here at AC. I have been reading voraciously for the past couple weeks and now have been able to formulate some questions which I haven't quite found the answers to.

I have a 20L which was set up on 7/12 (just over 3 weeks ago). I leapt before reading and am cycling with fish (I know, I know:headshake2: ). I presently have 4 zebra danios and 3 otos. I have a mixture of real and plastic plants. The real being: 2 java fern (I intend to move the ferns onto rocks or wood asap), 1 Cryptocryne wendtii, 1 bunch hornwort, and 1 bunch wisteria (Hygrophila difformis). I only have basic gravel for substrate.
My lighting is low, 17w flourescent which came with the hood.

My questions are:
1) Could I benefit from CO2? I read about the DIY setups and think that would be feasible. Would one 2 liter be enough/too much for 20gal?
2) What, if any, fertilizer, supplements, etc. would be useful for my tank?
3) Besides java moss (which I hope to add soon) what other plants might you recommend?
4) If I add shrimp at a later date, will that affect fertilizer choices?

Additional info:
I have a hob filter. Lights are on approx. 12 hours per day. I have been testing (using Mardel 5 in 1 test strips--I know better now, but it's what I've got until payday). As of today, Nitrate is 20, Nitrite 0, Hardness 120, Alkalinity 180, pH 7.6. I have a Mardel Live NH3 in the tank which reads 0.

Thanks for all the information I've already gleaned from other posts.

Carol

[Mgamer20o0]

1 you could add it but you would be better to add more light.
2 right now more light. once you get co2 going you might want to add ferts.
3 guppy grass water sprite Anacharis other types of moss
4 not really. i would go with dry ferts. find them cheaper and easier to do.

with a hob filter you have a high chance to gas out your co2.