Co2 Canister Position

[waterdrop]

Nice tank there charlie!

OK, that's a nice clear picture of the brass stuff on top of a CO2 tank for us beginners and the description of the little stubby thing on the right is clear, so if Dave or OM47 or other members with tank experience come along, perhaps we can see where this fits in to our discussion. Personally, this was what I expected, something up there hanging off the "stem" stuff, as opposed to any sort of device directly on the tank itself... but its been hard to tell after listening to various descriptions.

~~waterdrop~~

 

[kcharley]

Hi WD,

Thanks for the compliment on the tank.

As the discussion started with the position of the tank, I have a comment on that first. While doing my reseach on the valves, I came across a manufacturer's statement that was so obvious I didn't even think about it until I read it. Basically the tank must be upright for our purposes. This is because the majority of the CO2 is liquid with only a small portion in gaseous form. Thus, the tank must be positioned so that gaseous form can exit when the valve is opened. (I can only guess that the paintball gun CO2 works because they are doing momentary releases. They are more concerned with pressure than gaseous versus liquid form.)

As a newbie with CO2 I've got a couple of observations to share. At first, I tried to use a drop checker to get my CO2 to the recommended 30 ppm. I'm convinced that I don't have my solution right because it indicates I am well past 30 ppm but my fish are doing great. They are not swimming gasping for breath (I don't have a air pump running at night.) and while my plants are doing very well, they are not pearling. My point is I am going by what my fish and plants tell me and not by what the drop checker tells me. (I have the drop checker in a non-CO2 tank right now and it still says the ppm exceeds 30. I need to make a new batch of 4DKH water for it. )

The second observation is the water flow through the reactor. My first several readings I missed that the recommended flow is into the TOP of the reactor and out through the bottom. I initially installed it in through the bottom and out through the top. While this worked there was a slight bubbling noise, about one per second. By inverting the reactor, the bubbling noise ceased and the CO2 bubbles that do enter the tank are much smaller. I haven't had a gas build up in the reactor as some have (which is good because it doesn't have a bleed valve in it yet.) I'm guessing that I don't have a gas build up because I have a strong water flow through the reactor coupled with the gas shutting off automatically at night.

A third observation is that I have a slight bio-film on the water surface. Apparently this is common with CO2 and is worst when first started. This biofilm is part of the reason some with CO2 run airstones at night. I've minimized the problem by having my return positioned so that there is strong circulation with a very slight ripple at the surface. It's comical watching the fish. They will swim around happily in the middle and lower water and occasionally swim headfirst into the incoming water. At this point, they swim madly not making any forward progress. Eventually they go right, left or down and back to leisurely swimming. I like to think of it as their treadmill and I am waiting for their request for a 42 inch flat screen.

Greg

 

[s007]

As a newbie with CO2 I've got a couple of observations to share. At first, I tried to use a drop checker to get my CO2 to the recommended 30 ppm. I'm convinced that I don't have my solution right because it indicates I am well past 30 ppm but my fish are doing great. They are not swimming gasping for breath (I don't have a air pump running at night.) and while my plants are doing very well, they are not pearling. My point is I am going by what my fish and plants tell me and not by what the drop checker tells me. (I have the drop checker in a non-CO2 tank right now and it still says the ppm exceeds 30. I need to make a new batch of 4DKH water for it. )

Gos same problem here i got co2 drop checker added 4 drops of that stuff and the rest filled with aquarium water as stated in the manual. My co2 diffuser working like mad the fish is fine and plants grow great but the solution is still blue. I have made a smal video on my phone and attached below. Any suggestions why the solution does not change?

http/s159.photobucket.com/albums/t151/cy...-03-09_1512.flv

 

[aaronnorth]

it takes about 2hrs for the colour to change, so that means it is 2hrs behind. for example

green/ 30ppm @ 10.00am

this means it was 30ppm at 8.00am - make sense? There is a guide to DC in my sig.

 

[kcharley]

Gos same problem here i got co2 drop checker added 4 drops of that stuff and the rest filled with aquarium water as stated in the manual. My co2 diffuser working like mad the fish is fine and plants grow great but the solution is still blue. I have made a smal video on my phone and attached below. Any suggestions why the solution does not change?

[URL="http/s159.photobucket.com/albums/t151/cy...-03-09_1512.flv"]http/s159.photobucket.com/albums/t151/cy...-03-09_1512.flv[/URL]

My understanding is that a 4DKH solution should be made from DI or distilled water because other waters may have other acids that will affect the reading. I made my solution from a shop that claims it is DI water. Either they have added something to it or I botched the making because its green in a non CO2 tank. I may try another batch made from from distilled water but I don't see the point as fish and plants are doing great inmy CO2 tank.

 

[waterdrop]

Am enjoying it guys, nice clear writeup kcharlie, thanks for that! maybe Aaron can comment on whether that looks like the pressure relief valve in the picture (that's one of things that got us going in this thread aaron)

(excuse my absence, will be gone to other cities for kid sports (but hey, good LFS there... hmmm))

 

[s007]

it takes about 2hrs for the colour to change, so that means it is 2hrs behind. for example

green/ 30ppm @ 10.00am

this means it was 30ppm at 8.00am - make sense? There is a guide to DC in my sig.

Yes thanks ive read you thread about that but the thing is my co2 drop checked didnt change colour in a whole day! I have probably doubled the co2 ammount and still it statys blue. The bouble counter shows like 4-5 bps , my fish are ok as i watched them closley and plants too.
Any ideas?

Serg

 

[aaronnorth]

this is a pressure relief valve

What did you use as bromothymol blue?
Where did you get your 4dkh solution from?

 

[s007]

this is a pressure relief valve

What did you use as bromothymol blue?
Where did you get your 4dkh solution from?

It came with the co2 drop checker maybe youve seen they sell them on ebay green writing on white bottle 10ml "CO2 TEST" ive incresed even more co2 and now its starting to turn green at the moment since increase 5 hours passed and it turned dark /mid green
Do i need for it to go light green but noy yellow?

Cheers,
Sergey

 

[fish.com1]

this is a pressure relief valve

What did you use as bromothymol blue?
Where did you get your 4dkh solution from?

It came with the co2 drop checker maybe youve seen they sell them on ebay green writing on white bottle 10ml "CO2 TEST" ive incresed even more co2 and now its starting to turn green at the moment since increase 5 hours passed and it turned dark /mid green
Do i need for it to go light green but noy yellow?

Cheers,
Sergey

Blue= too little co2 (less than 30ppm)
green= right amount(30ppm)
yellow= too much (30ppm+)

 

[aaronnorth]

perhaps you didnt have enough CO2 then. If it come with the DC then it should be fine.

I always aim for a lime green to ensure there is enough CO2, but not too much.

 

[s007]

perhaps you didnt have enough CO2 then. If it come with the DC then it should be fine.

I always aim for a lime green to ensure there is enough CO2, but not too much.

Thanks for that i think now i got the right amount of co2 its light green but no hint of yellow in it! another thing i wanted to ask is under my dropchecker where the air is i get build up of some slime and quite allot of it! Is it co2 and is it normal as every 2 days i have to take solution with ropcheker out and clean it.

Thanks

 

[aaronnorth]

slime? a bit like surface scum?

 

[waterdrop]

Aaron (if you see this!), I finally remembered to chk back to this thread and there was another thing about it. You posted the good picture of the little pressure relief valve itself...

BUT, can you confirm the obvious for us newbies, its screwed into one of the brass stem thingies on the top of the cylinder, right? So the idea is that there is always some sort of stem and pressure relief valve on the bottle, even when taking it to refill, right? But the big regulator thing with the dials is screwed on later after you get home I guess?

[Also, in one of the other recent planted threads (Amunet, cat avatar I think...?) I've speculated to him that I remember some advice from you guys that its better to go with drop checkers such as you're describing here... for some reason I'm remembering that those electronic pH controllers (I'm remembering the green milwaukee ones?) are not really an advantage to have, not really desirable once you know what you're doing but I can't remember why now -- anyway perhaps you'd look over there if you see this -wd-]

~~waterdrop~~

 

[Dave Spencer]

WD, a CO2 cylinder is a pressure vessel so should, by law, have a pressure relief valve. The pressure regulator should also come with a relief valve.

The purpose of the drop checker is to give a good indication that my tank CO2 levels are running at 30ppm. It is done by adding a few drops of Bromo blue (Nutrafin low pH test kit) to the bulb on the dropper. Then you need to add a few drops of reference solution at a carbonate hardness of 4dKH, which is basically RO water with some BiCarb added until 4dKH is reached (this is actually not true, as the test kits measure alkalinity, not the KH, and sodium bicarb does not increase the KH, but will do for the purposes of this method). The 4dKH reference solution is pure, without any unwanted influence on its pH, unlike using tank water, so adding the pH test drops to the solution we should see a dark blue colour.

When the dropper is fitted below the water level in the tank, an air gap is trapped between the tank water surface and the reference solution. What happens now is that the amount of CO2 in the tank water will, over the period of an hour or two, equalise with the CO2 in the dropper air gap, and thus affecting the reference solution. The colour of the reference solution should change from blue to green, with green corresponding to a pH of 6.6 on the Nutrafin chart. Correlating a carbonate hardness of 4dKH against a pH of 6.6 and we get a CO2 level of 30ppm. If the solution remains blue then CO2 levels are too low, and if it goes beyond green and turns yellow then CO2 levels are too high.

The reaction across the air gap is :

CO2 + H20 => H2CO3

H2CO3 is carbonic acid, which changes the colour of the pH tester in the drop checker. You can see the reaction has nothing to do with the KH of the tank water, so CO2 can be added to water with 0dKH. My water is around 1dKH, I add CO2 at 30ppm, use lots of wood, and add acidifying ferts. I have never measured, nor worried about the pH....Amunet.

As I am sure you know WD, there are many other factors affecting the pH in aquarium water, all of which will be affecting a pH probe, thus making it very difficult to gain an accurate and steady CO2 level by measuring the pH.

The drop checker is far cheaper and, ultimately, the most cost effective/accurate method currently available to the hobbyist. It`s even cheaper when you make your own 4dKH.

Dave.

EDIT: for the record, I run with my drop checkers yellow, but with lots of surface agitation for the comfort of my fishes.