All of the CO2 questions (for my tank)

[nirbhao]

I've been reading and searching, finding a lot of useful information. However, it's all about situations that are slightly different from mine in important ways. I'm going to lay out exactly what I have going on here and what I'm looking for.

This is the tank in question.


It's 29 gallons. It doesn't have a lid and it's in an east-facing window. I've heard those are both big no-nos, but obviously I'm doing it anyway. The spouse likes it that way. The plants grow out of the tank and the sunlight is the main lighting. There's an LED airstone that I'll get to as well. The temperature is consistently 82° F and pH 7.4.

The filters are an AquaClear 30 and a gutted Aqueon Whisper 10 that now holds biomax and purigen. I've removed all carbon. Air is fed during the day through an AquaTop AP100, split with the 10 gallon and little dish that houses baby snails. Because baby Japanese trapdoor and rabbit snails are apparently super delicious to the gourami and blue ram. I digress... The air comes through the LED airstone and one of those $2 airstone bars. Our whole air situation started with an undergravel filter, which had to go once we switched to sand substrate.

This is my brand new as of today CO2 system.

Keeping it super high tech.

I drilled a hole in the lid and superglued a check valve, attached flexible PVC airline to rigid airline. It's currently delivering 38 bubbles per minute.

Stock is 1 dwarf gourami, 1 blue ram, 4 guppies, 7 Harlequin rasboras, 3 rabbit snails, 3 mystery snails, and a Japanese trapdoor snail who is currently isolated because the fish are treating her like a snack machine.

I get no algae. At least, if I do, the snails take care of it before I ever see it.

My plants are a little of everything, which is definitely part of the problem. I have two types of ludwigia, argentine sword, "asian water fern," java ferns, and microsword fully submerged. There's an acorus and some lucky bamboo partially submerged. They aren't dying, but they aren't thriving. Many of these plants were given to me when I asked a guy at Petco how dead he thought one of those plants in the tubes are. He correctly inferred that I am comfortable buying less than perfect plants and bringing them back to health.

After bringing all of these plants home, my carbonate hardness dropped out, although I can't really call it that given that it had generally been between 9 and 12. Regardless, we hadn't been adding any carbon, only using LeafZone once a week. We added Flourish Excel and I've been dosing outright absurd amounts but still my carbonate hardness peaks at 3.

My husband hasn't actually used the words, "Stop spending so much money on the fish," but he may as well have, so anything I do needs to be either cheap or something we can make. He's a fabricator and welder, and I actually suspect he would have a lot of fun working on a CO2 system.

Questions!
1. Are we doing it totally backwards running the air pump during the day and not at night? Should we be using the air pump at all?
2. How long is it going to take to get the dissolved CO2 high enough to give the plants something to breathe?
3. Is it okay to leave the CO2 line in at night?
4. What else?

Thanks so much. You guys have been a huge help with everything else I've done so far.

 

[Bert2oo1]

Don't run the air stone at all it will kill all your added co2. Make sure u have a one way check valve of the co2 line before it enters the aquarium so u don't get yeast in the tank.

Co2 should dose in straight away.

Are u running a diffuser to diffuse the co2? U can always put the line into your hob intake.

It's a good idea to put a splitter on the line so u can vent the co2 into the air rather than the aquarium at night. People have ran air stones at night to stop from over dosing but if u ask me that makes it harder for the co2 to get the good levels the next day.

If I was u and didn't have enough $$ for pressurised I'd buy a DIY kit off eBay or Amazon. U can get them really cheap and they have release valves etc so your bottles don't explode and u can also control your bubble count better.

38 bubbles for second!?!? U will gas your fish. I'd go no more than 3 per second.

Picture of DIY co2 setups u can buy:
First and better option of the 2 is the solid plastic bridge. It's called a D-501



Number 2 is the D-201
Does the same job but the fittings arnt as good.



I've used both of these systems with bicarb and citric acid as my generators.

U can turn these on and off and there is minimal risk of explosions.

Hope I've helped!

 

[nirbhao]

Make sure u have a one way check valve of the co2 line before it enters the aquarium so u don't get yeast in the tank.

Which way is the check? I thought the goal was to avoid getting tank water in the yeast solution.

Are u running a diffuser to diffuse the co2? U can always put the line into your hob intake.

I wasn't. I just moved the line into the Aqueon since its top is off anyway.

38 bubbles for second!?!? U will gas your fish. I'd go no more than 3 per second.

Per minute! That's like almost 2 per second. 38 per second would be its own powerhead!

... and there is minimal risk of explosions.

Pshaw. Ruins all the fun. Just kidding. I don't want explosions.

Hope I've helped!

Very much! Thank you! I'll look at more complete DIY setups.

 

[Bert2oo1]

I'd put the pipe end into the intake of your hob for better spread of co2 and dilution. As long as there's a check valve u should be fine no matter what way

 

[bullyboy]

I'd put the pipe end into the intake of your hob for better spread of co2 and dilution. As long as there's a check valve u should be fine no matter what way

Hmmm im not sure what you mean here but im starting a co2 planted tank and have been looking at my options for disbursement vs. just a diffuser.

Any pics or recomended tutorials?

 

[Bert2oo1]

Hmmm im not sure what you mean here but im starting a co2 planted tank and have been looking at my options for disbursement vs. just a diffuser.

Any pics or recomended tutorials?

You just put theco2 pipe that u normally put a diffuser onto into the intake pipe of your filter. Drill a hole in the basket on the bottom and push it into it. This way the bubbles get more time to diffuse into the water and then is spread better by the flow of your filter. U can do this with canisters too.

 

[Caliban07]

Hmmm im not sure what you mean here but im starting a co2 planted tank and have been looking at my options for disbursement vs. just a diffuser.

Any pics or recomended tutorials?

Some people places the output of their co2 underneath the input of their filter. The idea is that the bubbles get sucked in to the filter and trapped in the sponge splitting the bubbles up and increasing overall dissolution. Smaller bubbles have a larger surface area to volume ratio making it much easier for the co2 dissolve in to the water column.

 

[flchamp89]

The hole in the plate on the ac30 above the propeller is another option.

 

[Fresh2o]

The hole in the plate on the ac30 above the propeller is another option.

I've read about that. My only concern was where the air would go at start up (when flushing air out of the intake tube). Not a big deal though.

 

[Fresh2o]

With the yeast based DIY CO2 setup, you will want to add a container for capturing stray yeast and for counting bubbles. In the pic below, it is the third bottle from the left:

At the time I was using two 1L bottles as generators and a third 1L bottle as the aforementioned bubble counter. Check valves are used between bottles. The setup allowed me to swap out a bottle each week for maintenance without depressurizing the system.
For holes I used a 3/8" bit to drill through the plastic bottle caps. After cutting the end of the tubing at a sharp angle, I was able to pull it through the hole using needle nose pliers. No glue or sealant was used. The tubing I used was silicone; probably not the best due to its porosity, it was the easiest to work with. I did not use a diffuser so that kept the system relatively low pressure.
For the recipe, I used 1 cup of sugar to 1 L of warm water. A small portion of that (3-4 oz) was heated to about 120F in the microwave then allowed to cook slowly. As the temperature fell within the 105-115F range, I introduced 1/4 tsp of activated yeast. I let that froth up for 10-15 minutes before adding that to the sugar-water solution. This recipe would last 2-3 weeks. It would produce 1 bubble every 2-3 seconds. I ran it 24/7. No air stones used in the tank.
If I were to do it again, I would try the citric acid method as described in one of the posts above (the one with the kit). Cleaner mix and it allows you to turn it on/off and control the output as needed.

 

[flchamp89]

Works for me at 1-2bps

 

[nirbhao]

Brilliant. Thank you. You are all phenomenal.

With regards to the filters, we do keep the water level about an inch and a half below the top of the aquarium because otherwise the mystery snails try to escape. It seems like sometimes they just like to be out of the water for a minute or two. My entirely unscientific hypothesis is that they like to poop out of the water.

ANYWAY that leaves a decent waterfall effect. If the CO2 is fed into the water going to the waterfall, won't it just dissipate again?

 

[bullyboy]

So this wouldnt work on a cartidge type filter then?
(Like an Aqueon type)

 

[flchamp89]

Idk that filter but as someone said earlier. Run it into bottom of intake.

 

[Bert2oo1]

Should still work just fine as the co2 will be in dissolved into the water by the time it head down the waterfall. DIY co2 is pretty minimal but it does help!

 

[nirbhao]

So this wouldnt work on a cartidge type filter then?
(Like an Aqueon type)

We don't have a cartridge in the Aqueon. You pay $10 for the whole thing and then $10 for three cartridges you have to replace every two weeks, which means throwing away all of the beneficial bacteria every two weeks. Just nuts. Instead, it has a bag of BioMax and a bag of Purigen. I love the Purigen.

DIY co2 is pretty minimal but it does help!

At this point any CO2 is going to help!

 

[nirbhao]

Alright. After running this since shortly before I posted the original thread, my pH is now 6.8 and kH still 3. I have good dissolved CO2, but I'm a little freaked out about how much it dropped the pH in such a short period of time.

 

[PerfectDepth]

After bringing all of these plants home, my carbonate hardness dropped out, although I can't really call it that given that it had generally been between 9 and 12. Regardless, we hadn't been adding any carbon, only using LeafZone once a week. We added Flourish Excel and I've been dosing outright absurd amounts but still my carbonate hardness peaks at 3.

Great advice from others already- just thought I would mention that adding excel will not affect your KH since KH is only a measure of the amount of carbonate and bicarbonate anions dissolved in your water.

What is your water change schedule (volume and frequency)? KH at 3 is not an issue at all, but if you're worried about it dropping further the simplest solution is to do larger or more frequent water changes. It is possible that KH has dropped because some plants will start to use up dissolved carbonates as their source of carbon, but only once dissolved co2 has been depleted. Once you get co2 injection figured out, KH should no longer be used up by the plants since they will be getting their carbon strictly from dissolved co2 instead.

Also, I'm not sure that KH buffering is nearly as much of a concern as it's made out to be. Many people have success with KH at or near zero. For example low-light, low-tech, non-co2 planted tanks that hardly ever get water changes quickly end up with KH at zero. Also, breeders of delicate shrimp (crystal reds etc) use special soil substrates that intentionally and quickly deplete KH to at or near zero in order to achieve the very low pH that they require.

Air-stones are not desired with co2 injection because they speed up the gas exchange at the surface, which is not a big deal but you will be using more co2 to counteract it, and possibly have trouble keeping the co2 concentration consistent.

In a non-co2 aquarium, adding an airstone will help to return co2 concentration to equilibrium much more quickly, which is either good or bad (i.e. either raising or lowering co2 concentration). Equilibrium is the concentration at which co2 is entering and leaving the water at the same rate, and is estimated at 3 to 4 ppm. Co2 will build up overnight, and probably be slightly greater than when at equilibrium, giving an extra co2 boost once the lights come on which is great for the plants, so you don't want to run any airstones at that time. But then once plants start using up the co2, and co2 eventually drops below equilibrium concentration, running an airstone at that time will actually help to replenish the amount of dissolved co2.

 

[Bert2oo1]

Don't worry about ph drops. Mine drops from 7.2-6.6 when I'm injecting co2 over a weekly basis. The swings don't hurt the fish it just means your co2 is working
As long as your fish are still active and arnt gasping at the surface u know your good

if u do find your fish gasping then drop an air stone in for a few hours and they should go back to normal it's all about finding a balanced feed of co2

 

[nirbhao]

I do a 10 gallon change at least once a week. This week I did two because we added the seven Harlequin rasboras. Maybe that's faulty logic.

I'm less concerned about the kH being low (although I *was* concerned, so thank you) than I am about the sudden pH drop. Will it be possible to keep the pH at or slightly above 7? The rabbit and Japanese trapdoor snails will be fine down to 6.5, according to my research, but the mystery snails need at least 7. If it's not possible, I can move them to the 10 gallon.