diffusion problems...

aaronnorth

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Hi,

i am worried that my plants aren't getting enough CO2 (you are going to say up it i know). I am running 1BPS on my 60l (comes on 2hr before lights and goes off 1hr before lights) after 4 hours, my DC is still blue :? If you look at my tank (in my sig) you can see that it isnt heavily planted so this seems like a lot of CO2 to me, other than that it isnt getting pushed around enough. it is the opposite end of the output of my fluval 205 (680l/ph - 11x turnover). Diffused by one of those cheap glass ceramic fdiffusers on ebay, the bubbles get pushed along the side wall of the tank and then that seems it (some go in the filter) and i dont think my plants are getting much at the other end - any suggestions?

here is a simple illustration to try and show you :oops: :
diffusion.jpg



do you think it is ok or could i improve it?
 

JamesM

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CO2 bubbles don't need to come in direct contact with the plants, they dissolve in the water column. Try lifting the diffuser higher directly opposite the filter output - this sometimes drives the bubbles down and across the substrate.

The bbs doesn't really matter - every regulator will be slightly different and bubble size will differ. I run around 6 or 7 bbs in an 18 gal to get my drop checker green/yellow.
 

aaronnorth

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JAmesM said:
Put it under the filters output?
to do this it means i have to have the flow going along the edge of the tank which isnt that good IMO as there is less dead spots where it is now. also if i put it going along the back it blows the MM i have right over and that cant be too good for it :?
 

a1Matt

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My first reaction would be to say move the diffuse to underneath the spraybar as well.

... I'd also try to confirm if the problem is the dispersion of CO2 in the tank, the level of CO2, or both.

In practical terms I would move just the dropchecker to start with - putting it above the diffusers outlet. If the DC goes green here I would take that as a good sign that you are putting CO2 in. (If not obviously raise the BPS). This is a good starting point!

Next work onthe dispersion\flow.....

Even if it is not aesthetically pleasing to you I would then move the diffuser to under the spraybar just to see the difference it makes.

I'd repeat this process of moving things around keeping everything in one place for at least a day at a time and observe the DC throughout the day. When you get a good reading leave the diffuser but try the DC in different positions just to make sure it is getting everywhere.

I found mine works best with my reactor output under my spraybar. If I tilt the spray bar, or lower\raise it by just 1cm it makes a noticeable difference. Add that plant biomass changes over time and you realise that.... maintaining CO2 levels can be a bit#h but worth every bit of time you put into it!

Just my two penneth, hope it helps.
 

Ed Seeley

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IMO 1 bubble per second isn't really a lot of CO2. I think no matter how much you reorganise you're going to find that you will need to turn it up a bit.

To improve your distribution you might want to try positioning the diffuser right under the intake. This will then suck most of the bubbles into the filter. Don't worry as the microbubbles should dissolve well before they actually reach the filter and they will not harm the bacteria in there either. This should give you better results with the lowest possible bubble count.
 

aaronnorth

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thanks guys, i am now running 2BPS and with more CO2 coming out it is more noticable that the bubbles are getting blown around more :D

i will se what happens to the DC tommorow no i am running it higher and i will be back with the results ;)
 

durtydurty

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Ed Seeley said:
IMO 1 bubble per second isn't really a lot of CO2. I think no matter how much you reorganise you're going to find that you will need to turn it up a bit.

To improve your distribution you might want to try positioning the diffuser right under the intake. This will then suck most of the bubbles into the filter. Don't worry as the microbubbles should dissolve well before they actually reach the filter and they will not harm the bacteria in there either. This should give you better results with the lowest possible bubble count.
Ive moved mine underneath the intake of my filter ( ex1200 external ) and whilst it does a fantastic job of spreading the co2 Im worried about getting a build up of c02 in the cannister as every once and a while I get a rush of air into the tank which Im guessing is built up c02 thats not diffused by the time it reaches my cannister.

Would this cause any damage to my filter over time?
 

Spider Pig

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Had a similar problem when I had my co2 going straight into my ex1200 intake. Would get gas build up in the filter causing noise and big discharges every so often. Interestingly when I moved the diffuser under the spray bar so that the bubbles were blown around the tank, I found that the bubble rate was much the same.
 

nrwatson

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I am new to all this so apologise for any nonsense but had heard that co2 going into the filter would damage it
Neale
 

PM

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Email the manufacturers, that's what I do when I have a question about a product, and they are always very helpful! :)
 

Ed Seeley

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If you put huge amounts of CO2 into a filter then there is a possibility that it could cause problems. The manufacturers will tell you not to do it I am sure (I know Ehiem do). If you are putting them in as microbubbles then I would have thought it won't go into solution before they even reached the filter canister.

If you're concerned about that make yourself a reactor to go on the outlet.
 

Spider Pig

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I was quite surprised that more co2 wasn't dissolved even with microbubbles, especially going along about 11/2 meter of tubing before reaching the filter. For me the main concern was the noise and disruption to the tank. I can't imagine the microbubbles having too much effect on the impeller but may be wrong.
 
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Ed Seeley said:
If you put huge amounts of CO2 into a filter then there is a possibility that it could cause problems. The manufacturers will tell you not to do it I am sure (I know Ehiem do). If you are putting them in as microbubbles then I would have thought it won't go into solution before they even reached the filter canister.

If you're concerned about that make yourself a reactor to go on the outlet.
the best way to avoid any issues is to make sure you vasaline any o-rings during maintenance.. should avoid any drying out of the rubber due to co2 that way.
 
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