Oxygen and CO2 ...

[SkinnyChicken]

Does anyone test their water for its oxygen level? And if you have plants, are you supposed to (or is it even possible to) test for CO2 levels?

I only ask as yesterday I decided I hated all my unhealthy looking plants in my discus tank and so ripped them all out. I now have some Amazon Swords in there plus a few cutttings of my old plants that looked healthy enough to be going on with (not sure of the variety but they do seem to survive in the high tempature discus tank).

I was wondering if I could get away with just a weekly dose of liquid plant food? I have an airstone that is buried in the gravel at the back of my 80g tank which is currently switched on 24/7. I have my lights (3 tubes) on ten hours a day. I tested my oxygen level for the first time yestderday too and it was 5mg - though I have no idea what that means.

My KH is 3 which seems to be very low comparing to other members levels. Does this mean if I decided to introduce CO2 (which I have absolutely no experience with - and even less knowledge about) then this would cause my PH to start fluxtuating madly.

Do I switch off my airstone during the day, turn it back on during the night? My tank is well stocked and the discus are on the largish size so I'm guessing I will have to keep an eye on my oxygen level - but what level should it be for the fish and what level is going to be good for the plants?

I tried a non planted tank and hated it so I really need to keep my plants alive and looking healthy. My current tank temperature is 29 degrees Celcius.

I know that is a lot of questions but if anyone could offer any advice as a starter for ten, I'd be most appreciative.

[doug z]

You can moniter C02 levels with what's called a drop checker..

http://www.greenleafaquariums.com/co2-drop-checkers.html

Most have a solution that will turn green at 30ppm, which is what most planted tank enthusiasts agree is a good amount for the plants, without being detrimental to the fish.. It turns other colours for when you have too much, and not enough as well.. So if you wanted to play it safe you could play around until you got waht you figured was 25ppm or so by having the colour JUST about to turn green..

You don't want your air stone on 24/7..

It displaces all the CO2. Turn it on for 4 hours or so at night only.

A KH of 3 is good..

If you do go with pressurised CO2 you will be fine, as your buffers will be kept high enough with weekly water changes, and if you just run your airstone at night your pH and C)2 levels shouldn't fluctuate much at all..

The drop checker should be all you need to measure.. O2 not so much.. As long as you don't see the fish gasping at the surface they're fine.. Just make sure you run the airstone for at LEAST 4 hours..

You could get a timer so that the lights and the CO2 go off, and the airstone goes on.

[digital3]

You should be wary of the plants that you put in a tank with Discus. I've heard many plants do not tolerate the higher temps that Discus require. I think ILuvMyGoldBarb would probably have more info on this as he has more experience with plants and Discus.

[doug z]

If the Discus are ok with the 79 C, a little cold for them, but if you want plants..

Here's a list of plants from S. America that are ok with 79 C and soft, acidic water:

[SkinnyChicken]

29C is 84F Doug ... any warmer and I'll have to eat them :)

So I will need plants that live in anything above 29C ... the Swords seem to be okay and have been in the tank (albeit still in their pots) for a few weeks now). I could just use Swords, they are a nice plant and have interesting broad leaves.

My PH is 7 ... always has been, always will be I reckon ... my discus were bred locally and seem fine with it too ... so I won't mess with that.

[doug z]

Whoops.. Got them mixed up.. 79.. 29..

What do you have for a substrate, again?

Can you get fert tabs for the swords?

Here's a plant list for 84F or 29C, 6.5pH (results were the same for 7.0):

[doug z]

PS

Note that if you don't stick to S. America you have alot more choices..

Here's another I did for the same, just with a bit higher temp, no geographical parameter, and medium light requirements:

Of these,

S. subulata makes a GREAT carpet plant, your E. Amazonicus does fine, and for a mid-ground you could use Anubias barteri var nana..

What was your wpg, again?

Medium light is like 2.0 watts per gallon..

How high is your tank?

[ILuvMyGoldBarb]

First of all for the record, he has Amazon swords, but not necessarily Echindodrus amazonicus, there are 2 different plants that go by that common name. E. amazonicus is a narrow leaf and E. bleheri. E. bleheri is the more common of the 2 though.

As for checking your CO2, save your money, a drop checker is not necessary and IMO is an absolute waste of time. There is a very simple method for testing CO2 that can be performed with just a pH test kit. Take a cup of water and test the pH out of it. Record you results and then 24hours later take a sample out of that exact same cup. If the pH has risen by .5 then your CO2 concentration is 15ppm and if it has risen by 1 then it is 30ppm. Your target should be 15-30ppm. As for wild swings, you shouldn't have to worry about it. I ran pressurized CO2 on my tank at a level of 30ppm. That level would lower my pH, but it put it to a level that my Discus loved.

I keep my Discus at 82F or roughly 27C. I have grown the following successfully at those temperatures:
Dwarf Hairgrass
Altelnenthera reineckii
Ammania gracillis
Glosso
Dwarf Sag.
Echinodorus tennelus
Crypt wendetii
Red Rubin Sword
Melon Sword
Anubia barteri v. coffeefolia
Rotalla roundifollia
Echinodorus bleheri
Riccia

I had no problems at all with those plants. With that in mind, I did have a high tech setup with a 4x96w PC light strip, pressurized CO2, Eco-complete planted tank substrate, and a strict dry fert dosing regime. Not all the plants I mentioned will work with your setup though since the do require a good amount of light, CO2 and good fert dosing. None of my plants experienced any problems at all with the high temperatures.

[doug z]

First of all for the record, he has Amazon swords, but not necessarily Echindodrus amazonicus,


I've been PM'ing with him, and that's what Mark said he had..

I wonder if he has pics?

[xoolooxunny]

ILMGB, I don't use the ph check method for co2 measure anymore, because I have learned that the water left sit will continue to degas for up to 3 days, and that doesn't work for keeping an accurate measure for a planted tank. The drop checker, however, lets you just look at the tank and know whether or not your levels are ok, its little maintenance, and they are pretty cheap. plus they look cool:thumb:

[ILuvMyGoldBarb]

...plus they are not terribly accurate. None of the test kits available to hobbyists are extremely accurate but then again, they really don't need to be extremely precise. For the purpose of measuring CO2 you don't really need to be more precise then the degas method will give you.

The degas method is only accurate for 24 hours, that's why it's important to do the check 24 hours later. It doesn't matter what it is 3 days later, you only need to be concerned about the first 24 hours. The fact that it contiunues to degas for 3 days is completely irrelevent.

[fins_n_fur]

If the pH has risen by .5 then your CO2 concentration is 15ppm and if it has risen by 1 then it is 30ppm. Your target should be 15-30ppm.

@ILMGB - I'm a bit confused by what you wrote above. I thought CO2 helped to lower pH, not increased it. Or I'm a just tired and not reading this correctly?

[ILuvMyGoldBarb]

Yup, just tired. LOL That quote is referring to a sample of water that has been removed from the tank. The longer it sits out, the more CO2 will gas off thus raising the pH.

[fins_n_fur]

Yup, just tired. LOL That quote is referring to a sample of water that has been removed from the tank. The longer it sits out, the more CO2 will gas off thus raising the pH.
Now, if you had said it like that, I woulda got it the first time round LOL. Thanks for the clarification!

[SkinnyChicken]

Thanks guys ...

I made a start and now only use my airstone at night like Doug said. I will try the degas method over the next couple of days to see what CO2 level I get. And will go and have a look see at a few shops to see if they can recommend a pressurised CO2 system. I'll also take GoldBarb's and Doug's plant list and see what I can find - the only problem here in Western Australia is that we're still living 20 years behind everyone else so its difficult to get hold of things locally, that and quarantine is so strict that a lot of plants are really difficult to come by (you can't even get plants delived from the eastern states!!).

You guys are just a bottomless pit of great advice :)

[smaug]

Yup, just tired. LOL That quote is referring to a sample of water that has been removed from the tank. The longer it sits out, the more CO2 will gas off thus raising the pH.
does that method work if you ph is chemically adjusted with an acid buffer?

[ILuvMyGoldBarb]

That I honestly don't know smaug. It think it's something you would have to test. I've never had to use a buffer (6.2pH out of the tap :) ) so I've never had occasion to try it.

[digital3]

...And will go and have a look see at a few shops to see if they can recommend a pressurised CO2 system...

Best Co2 systems you can find:

http://www.bestaquariumregulator.com/index.htm