Injecting CO2 in a softwater tank

[yhbae]

My water is pretty soft, at 2 KdH. In my community tank, pH is very stable at 7.4. (This means super low CO2 level).

I'd like to add some more attractive plants, as all I have are java moss and java fern.

I've been reading up on building DIY CO2, and now I've convinced myself to build one.

The only thing that worries me is the pH. I studied the chart that shows the relationship between KH, pH and CO2 levels. At my KH, the pH level could seriously drop if I inject some CO2... I suppose I can compensate that by adding more KH (baking soda/crushed coral), but how do you ensure that the level stays constant? I don't want to be measuring pH every day just to keep nice plants alive!

On further note, I believe all of my species in the tank can handle lower pH except for one - platies. Would this be correct?

Species list:

- Platies
- Harlequin Rasboras
- Blue Rams
- Panda Cories
- Bristlenose Pl*cos

Appreciate any feedback.

 

[madasafish]

I can confirm your last suspicion. Platies are generally a harder water/higher pH species. They thrive in water with a pH between 7 and 8.

Mind you, a sudden drop in pH is good for no species, even those which prefer acidic water.

My suggestion! Are you (ethically or otherwise) opposed to using certain chemicals in your tank? I'm not... though this only applies to an extent. I use a great buffering solution called "Neutral Regulator" by SeaChem. It keeps my planted tank's pH at 7 rain or shine.

**A somewhat incredible story--despite the addition of CO2 to my 10 gallon tank recently (at 70-litre levels, which are quite high for a 10 gallon) my KH remained at 5 and my pH at 7. This is astounding! Allivymar found her KH dropped to 2 or 3 and her pH to 6.4 (roughly--can't remember the exact numbers) when she used the same unit in her 10 gallon. This stuff works! I use it in all my tanks and have never experienced a pH swing. In my 55, my pH has been 6.6 (using Seachem's "Discus Buffer") for several months without a waver.

So, look this stuff up... http://aquariumpros.com/aquaprostore/prods/SCH03040.shtml

Nope, I'm not employed by Seachem...

 

[betowess]

Doesn't this Seachem stuff adjust PH only? One would still need to add a little baking soda or CC/oyster shells to bring the KH up to a decent 3 or 4 dkh, wouldn't you? Which is easy enough to do.

And wouldn't injecting CO2 drop the PH at night unless you add airstones or use a solenoid to shut down the reactor etc? At two degrees KH the CO2 absorbtion by the plants would be incredibly high.... Pearling bubbles to the max.

 

[madasafish]

That's right. Neutral Regulator will only work on your pH. (How it maintained my 10 gallon's KH is beyond me...). And unless you want to manually shut on and off your CO2 injector every morning and night, you will need a solenoid (plugged into a timer, this will turn off your CO2 flow at night).

BTW, many plants (CAM photosynthetic and perhaps C3 and C4 photosynthetic plants) respire CO2 at night though they produce oxygen during the day. Though they are "producers" in the ecological sense, they still use the energy they produce (during the day) at night to run metabolic processes. This is why a solenoid is important, as you'll infuse your tank with CO2 the plants won't use at night. Time the solenoid to turn off the CO2 as your lights go out and you solve that particular problem.

Urg. A CO2 injection system with solenoid, bubble counter, reactor, tank etc. ain't cheap though... I'm in the process of buying one!

 

[Guest]

Ok, first off if I'm going to look up a information on a Seachem product I always go to www.seachem.com

Second thing is Neutral Regulator works using PHOSPHATE buffers. madasfish, I suggest you test the level of phosphates in your tank. In a planted tank with mid to high light levels high levels of phosphates can cause no end of problems.

Now if you need to adjust your water in a planted tank the only buffers you want to add are carbonate based. The reason being is that the pH/kH/CO2 chart assumes that the only buffers in the water are carbonate based. madasfish will have a very hard time figuring out the CO2 levels in their tank due to the use of phosphate buffers.

Now on to the question yhbae asked. You should raise your kH up to a minimum of 3 dkH, a little higher would not hurt either. Of course raising the kH is also going to raise your pH a bit. But the CO2 will bring it down. You did not say what size tank we are talking about here but DIY CO2 is hard to do correctly on any tank over the 30 gallon size. The other question I have is about your lighting levels? If you don't have the light to support other plants all the CO2 in the world is not going to help at all.

 

[madasafish]

Um... it's madasAfish... just one fish.

But thanks for correcting me on the phosphate issue. I've only ever used this product with great success, so I can't speak to its deleterious qualities. Are you sure that this product really offsets phosphates hugely in a tank, or is this just a conclusion given the general *possible* issue with phosphates?

And of course... Seachem.com. duh.

 

[Guest]

Sorry about the name. It was early in the morning.

All I can say is test the phosphates in your tank. If the nitrate-phosphate ratio gets too far out of whack you will have problems. These types of products work very well in FISH tanks but really are not suited for planted tanks due to the higher light levels.

 

[madasafish]

Advice taken!

 

[yhbae]

My suggestion! Are you (ethically or otherwise) opposed to using certain chemicals in your tank? I'm not... though this only applies to an extent. I use a great buffering solution called "Neutral Regulator" by SeaChem. It keeps my planted tank's pH at 7 rain or shine.

Well, I am somewhat reluctant to use chemicals... So far, I've been using baking soda to increase pH (during water change) and peat moss for reducing pH (in the filter) if I must change pH for breeding purposes. My community tank takes whatever pH my (aged) tap water provides.

 

[yhbae]

Now on to the question yhbae asked. You should raise your kH up to a minimum of 3 dkH, a little higher would not hurt either. Of course raising the kH is also going to raise your pH a bit. But the CO2 will bring it down. You did not say what size tank we are talking about here but DIY CO2 is hard to do correctly on any tank over the 30 gallon size. The other question I have is about your lighting levels? If you don't have the light to support other plants all the CO2 in the world is not going to help at all.

I guess adding some baking soda per each water change wouldn't be that difficult. In fact, I did leave some calcium carbonate stones in the tank even when I knew what they were to reduce the chance of pH crash. So far, my pH in the tank doesn't budge - statys dead constant.

My community tank is a 25g, although I am in the process of setting up a 33g. I was going to move the whole content of 25g into 33g. Since I bought the whole thing used, it came with 120w of lights, giving just under 4w/g which would be ok for most plants?

So, DIY CO2 is not a good idea for 33g?

Appreciate any further feedback!

 

[Guest]

I can be done. You just need more bottles. Say at a minimum a couple of two liter bottles. But at almost 4 wpg the fluctuating nature of DIY CO2 is going to cause you no end of problems. You might want to run a trio of two liter bottles and see how it goes.