new to CO2, built DIY HOB CO2.. expert check?

I have a 20gal. lowlight planted tank, no ferts. Why do I want CO2?
My water level is generally low for my water cabbages and I have 2 HOB filters, and the tank gets direct sunlight.
anyways, I have 2 20oz. bottles, one with:
1/4c. sugar
a few tablespoons(less than 1/4 bottle) water
flick of baking soda
flick of cornstarch
approx. 1/16th tsp. bakers yeast
The second bottle is a bubble-counter/bubble washer.
There is, of course, a check valve on the tube going into the tank.
no diffuser on the end yet, I figure it will be pumping air bubbles for a while anyways until CO2 actually reaches the end of the hose... any suggestions for a diffuser?
I happened to have a metal hook with a ribbon that formed a loop with a snap(came with a belt). it hooked onto the rI'm of the tank quite nicely, and, using a paperclip and string, I'm hanging the bottles from the loop. Out of sight, near the tank, and yet accessible, so it seems like a good idea to me.
I will take pictures if I can find the camera.
Anything I'm forgetting?

 

Hello GemstonePony,

Hopefully you will receive some replies today!

Ken

 

I have put a small piece of balsa wood as the diffuser, and added a little less than 1/4 tsp. yeast. no fish gasping at the surface yet, and there is 1+ bubble per second.
Edited to add pics. unfortunately, my sister is using the camera for a project for school, so these are from my phone.
Pic 1 is the end with the balsa wood diffusor (and my Dwarf Gourami)
Pic 2: (from top looking down) triangular grey blur is the ribbon, turquoise lines are the yarn the bottles are hanging from a paperclip hook on. That way they can be easily removed for refilling, etc.
Oh, and incase anyone wonders, the tank is NOT located directly in front of a window. that was a reflection from the window beside the tank.

 

bumping, and saying by "expert" I mean forum people with ANY experience of such things.. I consider those on this forum "experts" with their collective knowledge. I forgot when I labeled the thread how modest everyone here is.ops:
Thus, this thread is not addressed to experts, but to almost any person who is reading this!

 

Looks like you've got a good start. CO2 generators are usually 2 liter bottles to avoid having to replace the yeast mix every couple of days. The larger volume of water will keep the yeast alive, producing CO2 longer. You do not want to let the mix completely die out as this leads to CO2 fluctuations and algae.

The best diffuser I've ever found is a small bit of cotton, shoved tightly into the end of the tubing for a diffuser. The bubbles are extremely tiny and easily dissolved into the water column.

If you are adding CO2, you probably should be adding a small amount of ferts, otherwise you'd end up with an imbalance. The simplest way to estimate CO2 levels is to monitor your pH. 30 PPM CO2 will drop pH 1 degree.

Run an O2 line overnight while the lights are off to ensure the CO2 does not build up too much. Turn it off about 1 hour before lights on; and on 1 hour before lights off.

Check out the links in my signature. They may help answer any questions you may have as well as providing several mix options to try.

Good luck.

 

You do not want to let the mix completely die out as this leads to CO2 fluctuations and algae.

Thanks for the heads-up, I'll keep an eye on it. I actually want algae growth as I fear my nerite snail isn't getting enough to eat, but I don't want to stress the fish out to much.

If you are adding CO2, you probably should be adding a small amount of ferts, otherwise you'd end up with an imbalance.

I'll get some ASAP, but between the ridiculously hard water and messy eaters I don't think it's necessary at this point.

Run an O2 line overnight while the lights are off to ensure the CO2 does not build up too much. Turn it off about 1 hour before lights on; and on 1 hour before lights off.

Thank-you for the heads-up.. instead of running a bubbler, I simply take the CO2 line out and let it pump CO2 into the air.. The HOBs splash enough, they might as well be bubblers. I'm hoping with me supplying CO2 during the day and just plants providing it at night, the CO2 swings won't be as extreme. Should I not be doing that?

The best diffuser I've ever found is a small bit of cotton, shoved tightly into the end of the tubing for a diffuser. The bubbles are extremely tiny and easily dissolved into the water column.

I'll switch the diffuser to cotton then, thanks for the tip. Oh, is there any particular brand of cotton? or anything I should be careful of as far as what cotton I should use?

 

I use a piece of those cotton makeup remover pads. Any dense cotton should work though. I pack it in tightly with the end of a scissor and cut off any portion sticking out.

While I can understand you want algae to grow, fluctuating CO2 levels always lead to BBA, which most aquaria do not eat.

As you have HOB their splashing will release CO2. In one of my smaller tanks, with a HOB, I've found that I do not need an O2 line. The HOB takes care of it by keeping the water level down about 1 inch. You probably do not need to remove the CO2 line at all. Just monitor your pH changes throughout the day and any signs of stress with your fish.

With growing plants, there is a balance between lighting, CO2 and fertilization. All 3 components must be kept in balance for healthy plants and growth; and controlling algae. Being as you have a low tech tank, I'd suggest using Seachem Flourish Comprehensive as a plant food and dosing 1-2 times a week.

 

fluctuating CO2 levels always lead to BBA

oh, I thought that was due to low CO2 levels, not fluctuation levels. Thank-you for correcting me!

As you have HOB their splashing will release CO2. In one of my smaller tanks, with a HOB, I've found that I do not need an O2 line. The HOB takes care of it by keeping the water level down about 1 inch. You probably do not need to remove the CO2 line at all. Just monitor your pH changes throughout the day and any signs of stress with your fish.

My fish have been acting perfectly normal all day, so I think I'm fine with what I'm doing.. I can't monitor it at night though, so I'm scared to risk suffocating them w/CO2 @ night. Also, although both my HOBs splash I have a bit of Java moss stuck in the larger one so that some of the water flows over that and into the tank.. It helps with the noise level (since this tank is in a guest bedroom, that's kind of important), but I'm not sure how much it impacts the aeration.
Is there a ratio between how much CO2 you pump into the aquarium and how much the plants release at night?

With growing plants, there is a balance between lighting, CO2 and fertilization. All 3 components must be kept in balance for healthy plants and growth; and controlling algae. Being as you have a low tech tank, I'd suggest using Seachem Flourish Comprehensive as a plant food and dosing 1-2 times a week.

Thanks for the suggestion, I'll look into getting some.

 

A 2 litter would better and I use 1/2 teaspoon of yeast and 1/2cups of suger ,get about 2 weeks or better and my stay on all the time but at night I have more air pump that turn on with a timer.if you use 2 two letters start one up lets say one week and the other bottel up the next week and keep alternating them that has worked really well for me ,, for many years

 

I know, but 2L won't fit behind my tank and if this set-up is permanently visible I will be banned from dosing CO2 DIY. Which is the only way I can afford.
at night I just stop pumping CO2 into the aquarium, and in the morning I start dosing again. seems to be working fine, no sign of BBA.