Going compressed

[reiverix]

I've just ordered this (http://aquariumplant.com/cgi-bin/cart/pr840.html) regulator as I'm fed up with maintaining DIY CO2 on a 75 gallon.

What would be a good starting point for bubbles per second?

I still need to get the CO2 tank but is there anything else I'm missing here?

[Timmain42]

Make sure you have CO2-resistant tubing (ozone-safe tubing works as well). It's good that you have a bubble counter already attached.

Do you have a reactor or ladder yet?

I personally have gotten into the "1 bubble/second/40 gallons" method. Depending on how densely planted your tank is, you might have to up that a little.

[djlen]

Just start at one or two bubbles/sec., check for content, and adjust from there.
Remember, kH must be a minimum of 3.0°H.

Len

[reiverix]

I have this (http://www.aquacave.com/co2_diffuser.htm) diffuser. It's also got a bubble counter on it so will it interfere with the bubble counter on the regulator?

My kH is at 5.0° and pH hovers around 6.6 to 6.8 which isn't too bad for DIY on a 75g. But it's just a hassle maintaining three 2ltr bottles so I'm kind of excited about getting a compressed setup.

[Timmain42]

It should not interfere. Len?

[djlen]

Huh?

Len

[Timmain42]

Oh, I just thought you might have an additional opinion. Sorry.

[geoffgarcia]

all the diffusers I've tried (about 4) have been useless garbage and just end up cluttering the tank to boot!
I recommend pluggin the tubing into a canister intake

[anonapersona]

The most important thing is to start SLOW. Sometimes the heat from the solenoid can affect the setting on the valve, so be sure to check it all frequently for the first few days.

It may take the fish awhile to adjust to the increased CO2, I think I read that they have to adjust metabolically to it, but don't quote me on that. You want to have a chance to know how the CO2 builds up and pH drops overnight, so you don't get any nasty surprises in the morning, as well as how it is used up during the day. Every tank has different consumption and escape rates, and you will want to examine morning and evening pH to see if turning the solenoid off is a good option for you.

I actually started out at 6 - 10 bubbles per minute with pressurized, since that was the rate the DIY usually ran at. After I was certain that the fish were fine, I increased to 17, then a bit more, not really sure of the count, but I hit my target pH, so whatever, I know it is OK. I went really slow, I think I took a few weeks to go to the current setting, after each adjustment I'd wait for several days to see how it went. Underdosing is better than overdosing.

[reiverix]

So I now have the regulator and I picked up a 5 pound CO2 tank during lunch break. I'll set it all up after work and monitor the PH/KH during the evening.

I'm not sure about hooking up a timer though or should I just leave it to run overnight. I read conficting views about this. My KH is fairly stable at around 5dH. Basically I'd just prefer to have the thing running constantly.

[mrk442]

You can bubble into your cannister but you will have a lot better results with either a power reactor http://plantedtank.net/co2reactor.html or a In-line reactor http://www.gwapa.org/articles/inlineco2reactor.asp In-line reactor is the best bet if you want to not add equipment to your tank and still get max efficiency I personally use a power reactor and love it its well worth the added cost and having it in the tank to me but if my canister had enough flow i would probably go with and in-line. Especially with a 75 gallon for a tank that size you are injecting a fair amount of Co2 and you will get a lot better results with an active method of diffusion.

Just my .02 hope it helps

Matt

[geoffgarcia]

You can bubble into your cannister but you will have a lot better results with either a power reactorI cant imagine why you would get better results using either of the reactors you suggested than simply running it through a cannister filter (and the websites didn't explain why there would be any benefit), could you explain why those 2 would work better?

I'm not saying that they wont work at all, just that I have a hard time believing that running the co2 over a handful of bioballs in a prefilter/reactor is going to have a meaningful impact...those bubbles are just gonna whiz through that unscathed like Priest Holmes through a defensive line...

[mrk442]

those bubbles are just gonna whiz through that unscathed like Priest Holmes through a defensive line...

Good Analogy but flawed the bio balls are present to increase turbulence this aids in diffusion by creating a larger surface area for diffusion they are not present in anyway to to stop the bubbles from escaping the reason that the diffuser works is that water is flowing down through the diffuser the Co2 bubbles rise thus as long as your diffusion chamber is long enough no bubbles escape they are just churned over and over again until diffused into the water if you use a in tank reactor you just place a sponge at the bottom that allows Co2 rich water to escape but bubbles are trapped and drift backup to be churned over again.

Obviously if you have the flow through the diffuser going upward "I am assuming this is what you where thinking" they would just bubble right past the bio balls out the chamber and into the atmosphere .

Depending upon the amount of Co2 you are injecting "a fair amount to get a good level in a tank as large as a 75 gallon injecting directly into your canister filter can cause problems as the Co2 can and will build up in the filter in a undissolved state or escape undissolved back into the tank where the bubbles just float right out of the tank "wasted Co2" try injecting Co2 into your filter and checking your Co2 levels than try with the same amount injected into a power or in-line reactor and you will see an increase in your Co2 levels. Bubbling into a filter is a common method and works just fine for many people but since the trouble has been spent to by a good regulator with solenoid it would be a shame to miss out on the full benefits that this system could offer just because you lack the optimal diffuser especially when it can be made so simply and easily.


Hope this helps clarify things a little I know it can be a confusing at times :)

Matt

[geoffgarcia]

yep it does make more sense, your right, I wasn't assuming that the flow would be going upward, I must have missed that part in the websites explanation.

At any rate, are you sure that air bubbles (co2) can actually "drift back up" in a current of 200+ gph? That Rio600 in the example puts out 200gph, and the eheim the one guy was talking about puts out 250gph. I use a filstar xp2 and it puts out 300...
Thats a lot of force...
I could see air bubbles staying afloat maybe in 100gph...
thoughs?

[Captain Hook]

I've heard you do not want to inject CO2 into canisters if they have top-mounted impellers.

[mrk442]

Good point of top mounted impellers can become air locked from time to time. I can tell you from experience that at 100gph there is not nearly enough water movement to power a reactor of any decent diameter the Co2 just pools at the top and the water just kind of streams through the Co2 bubble. You need a good deal of water movement and because the rector is of larger diameter than the tubing the water flows quicker through the center then the out sides you can watch the bubbles get blasted by the water at the inlet flow down buffeted by the turbulence created by the bio balls and than float right back up along the sides "most obvious anyway they really look like they are floating up and down everywhere but along the out sides you can see the up flow" They float toward the top and than get blasted again the water inside a chamber like this creates a current inside looping from top to bottom quite interesting to watch actually. I have seen this system used on tanks from 20 - 250 gallons quite effectively and you can buy diffusers that are for even larger tanks "one that comes to mind is good to 500 gallons" I have a link to a great inline reactor page at my house that i will post a later today/tonight. Basically the size of your reactor depends on a few things the amount of Co2 you inject the flow rate of your pump and space available obviously. In general most of the bubbles even on very high flow rates don't seem to get more than 7 inches down the reactor but obviously that varies with the size of the chamber for super high flow systems a wider and or longer chamber may be needed.

This is a tried and true method for diffusing the large amounts of Co2 that are required for larger tanks obviously on smaller tanks other methods may work but the larger the tank the more you lose by having an inefficient reactor and you can only inject so much Co2 into a canister before you start seeing problems.

I don't know if you are the type of person that likes to experiment. aka play with things :) but if you are and have or can obtain a power head that has a relatively high flow try taking the end of a gravel vac and pluming it into the power head stuff a sponge or filter media in the end and fire it up its really pretty interesting to watch the bubbles churn. Another thing i have seen done is take a nice long clear water bottle or something similar Drop a handful or two of bio balls or something that will not block the flow but will create turbulence in the bottle than drill the top of the bottle to the size of the hose you run from your canister "assuming you have a fairly high flow filter" silicone it in place and than do the same on the bottom of the bottle create some sort of loop in your system so that water can flow down through it and than exit back into your tank like normal you will be surprised how efficient this can work and if you take a little time you can make this a nice clean install that is more efficient than just bubbling it into your filter and does not clutter your tank.

Obviously this may not be needed and it depends on the size of your tank but if you have a large enough tank to warrant the effort i would definitely suggest giving it a try i will be building another one soon and i will try and take pictures of the build and it in use if you are interested i can send you a copy or anyone else that would like one for that matter:)

[geoffgarcia]

great explanation! thanks!
I'm going to have to give it a try!

[mrk442]

Glad to hear it I give it a try and see what happens your first one might take a little bit to get right i went through several before i found on that worked for me make it to short and bubbles escape make it to long and its larger than you need it mind you larger is not a problem it just takes up more space and i am a tinkerer so i had to play with it till i had on large enough to diffuse all my Co2 not to large.

here is a great diagram of a power reactor http://www.csd.net/~cgadd/aqua/diy_reactor.htm

Anouther great site
http://users.ev1.net/~spituch/Steve's%20Page/Aquarium/hardware/DIY%20CO2/DIYco2.html

Here is a site where the have diffusers for sale i have included it because it shows just about every major type of diffuser there is from simple ladder type to the in-line

[reiverix]

Thanks for the reactor details. One day I might get down to making one but for now my diffuser isn't too bad. It lets out tiny bubbles that get dispered with my cannister filter outflow.

The one thing that's puzzling me is I've been running the compressed CO2 for over a day but my PH has stayed around 7. I've increased the bubble count to 1 bubble per second. When I was running DIY, my PH was always around 6.7. Should I increase the bubble count? I know there's no leaks as I tested all the seals with soapy water.

Having said all that, I have no idea what would be the bps on a 75g with compressed CO2.

[mrk442]

Take a look here
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

This page explains how to measurer your Co2 level i seriously doubt you are even making a dent on a 75 gallon with only 1 bubble a second.