Advice On Co2

[xoedusk]

Would really love our 20 gallon long to be more planted than it is now, and for those plants to be healthy. Currently, we have 18 watts of non-reflected fluorescent in there. The pH is very stable; has been 7.2 each time we've measured it. Today I measured the KH to be 2 degrees. The tank inhabitants are: 3 platies, 5 harlequin rasboras, 3 panda cories, an unknown number of platy fry, which will eventually be given away to new homes, and finally some amazon swords.

On the way is a 55 Watt compact fluorescent fixture, the popular Nutrafin carbon dioxide system, and some Seachem liquid fertilizer.

I want the whole system to be as safe as possible for our fish, which I think means no chance of overdosing CO2, no pH crashes, no drunk fish from overflowing yeast mixtures, but also minimal maintenance possible. I'd rather not have to add baking soda (biocarbonate of soda) dailly to keep everything healthy.

So I'm wondering what the best way to do this is. I'm thinking the KH needs to be raised somewhat. But would like the pH to remain close to 7, as our pandas and rasboras prefer acidic to neutral, but platies prefer slightly basic water. I dont know how possible it is to "aim" for a certain CO2 level with the yeast Nutrafin system -- but I'm thinking 20 ppm a good start. So somewhere between 5 and 6 dKH means I'd have a pH of about 6.9.

Am I thinking of this the right way? Or is my CO2 concentration hard to control? If it is hard to control, should I then adjust the KH manually (with baking soda) to get the desired pH? I would appreciate any input -- don't want to risky any fishy's life for better plant growth.

 

[Underwurlde]

When I read your post I thought...

Trying to control pH is very awkward.
With a nutrafin CO2 kit I doubt you'd overdose but keeping it stable. is the trick.
More yeast = more bubbles that run out quickly (unstable)
Less yeast = less bubbles that last longer (more stable).
Make your own mix using 1/4 tsp of yeast with sugar to recommended level (no 'activator' or whatever it's called).
(I think fluctuating CO2 = greater risk of algae?)

I think aiming for 20 to 30ppm is the goal but depends on pH & KH and the number of plants you have and the type of plants you have if you are talking about 'optimizing' your set up (very difficult to do IMO).

Overflowing of yeast is caused by moving, tipping or banging the canister. I think if you feed the outlet into another (empty & sealed) container and then another hose to the ladder works to prevent this. I don't think that if this DOES get into the tank it is actually all that bad for the fish....

Then I thouhgt....

If I wanted 'more' and 'stable' CO2 then I would be thinking of a canister setup perhaps - but they can cost alot. Constantly fiddling with baking soda, pH & KH is just beyond me. Also, to successfully control pH you would not be using tap water, but rather RO water and working up your KH manually using a set dosing regime (or is this what you're talking about?).

Andy

PS
Are you using EI techniques?

 

[xoedusk]

No EI. Going to use Seachem Flourish only and see what happens.

Am I best setting KH to 4 using baking soda (at each water change), running the Nutrafin CO2 at 1/4 tsp., and just letting the pH goes where it goes? I can turn on the airstones at night if need be.

 

[Underwurlde]

Am I best setting KH to 4 using baking soda (at each water change), running the Nutrafin CO2 at 1/4 tsp., and just letting the pH goes where it goes?

I would not add baking soda & let the tank 'sort itself out' and let IT naturally stabilize.

But that is just me. I don't really adhere to fiddling with 'nature' (I know, I know).
So I'd say to you, if you want control over KH then that's up to you... I wonder what the general concensus is. The thing is, if your not starting with a blank sheet so to speak with your water by using RO and instead using tap water - tap water will have a lot of GH & HK & pH fluctuations in it (some water companies inject CO2 into the water as well I believe). If you use a standard dosing method (not testing for KH first) then you could end up making things worse.... Complicated science this.

Don't use an airstone with CO2. The surface agitation causes a reduction in CO2!
If you therefore use an airstone at night your CO2 will fluctuate daily...

Alot of people do however turn CO2 off at night (when the lights are off). What the advantages and disadvantages of this are I have yet to research properly.

Andy