Will this work?

[bossteck]

Hi Folks,

I am toying with the idea of extending the outlet of my tank (with sump) and injecting co2 into the outlet at the same time. Picture speaks a thousand words... need your opinion if the idea will work.



This is the side view of the tank now. Water level is at the top of in-pipe, water will overflow into the pipe, into the sump, go thru all the media, and be pumped back into the tank. As you can see, the return pipe is quite long but I have made a mistake in getting the tank maker to place the elbow at a level that's quite high. In hindsight, I feel it's better to have it lower for better water circulation.



this is the first version modification I have in mind.
1. extend the outlet of the sump system so that the elbow is lower in the tank (blue portion)
2. drill a small hole and screw in a air tube connector. I will then connect the co2 tube directly to the connector, given that the return pipe is so long, i am guessing the co2 will have plenty of time to get dissolved without causing any problems for the pump in the sump tank.



This is the second version of my idea.
1. leave the outlet alone
2. drill a hole, insert air tube connector to the outflow pipe at the area just above the pump, feed co2 into it.

Some potential problems/restriction.
1. the flow of water could be so fast that all the co2 are simply forced out before they get dissolved.
2. there's currently a tiny hole at the return pipe above the elbow, just below the water level, it is suppose to break the siphon effect should the pump be switched off so water from the tank will not continue to flow into the sump via the outlet.
3. as far as possible, i want the hole to be in an area where water leaks (if any) will flow back into either the tank or the sump.

Welcome all comments.

[Johnc]

If you want to dissolved the CO2 through the piping, your second version would probably work better. Some CO2 may escape out of the suction-break hole, but I think it would not be much. For your first version, your CO2 will probably come out as fairly big bubbles. Why not connect an internal reactor to your outlet?

/John

[armani]

why not put a co2 diffuser in ur sump tank? cause if the sump tank is in a cabinet then not messy...

[bossteck]

Hi Johnc,

Thanks for your reply.

Currently I am using an internal reactor (those green plastic one with 3 bio balls inside), it is powered by a separate powerhead. I did some testing and realized that the co2 level in my tank is very low, when i crank up my co2, they will get expelled as tiny bubbles (ie, not fully dissolved).

Which is why I am currently thinking of how I can maximize the amount of dissolved co2 going into the tank. (the sump system is not helping).

Based on your experience.

Should i
1. get a bigger reactor (perhaps those with 6 bioballs? Does it matter?
2. connect the current outlet of my reactor to a rain bar? Does it help?
3. do the modification i destribed in this thread (version 2)

I am leaning towards option 3 because I'd like to have as little equipment in the tank as possible.

[bossteck]

Hi armani,

I started off doing that. Having reactor in sump tank. But realized co2 too low, and if I were to crank up the co2, they don't get dissolved enough as escaped quite readily.. since the water level in the sump tank is quite low (compared to the tank).

[Johnc]

If you use the green plastic reactor, I think won't need a separate powerhead unless your return pump is just too powerful.

I don't think a bigger reactor will help. In my own experience, the additional bio balls will simply 'sit idle'. Only the top one or two will spin to help to breakdown and dissolve the CO2... though the bigger column on the reactor may trap more CO2 so that more gets dissolved before escaping as bubbles.

I would personally try injecting CO2 according to your version 2 modification. But if that does not work because the flowrate is too high, I would attach the out let to the reactor after sealing the CO2 inlet to it. I.e. injection in the sump, but letting excess to collect in the reactor for further reaction.

However, you can expect CO2 losses from the very fact that you are using a sump.

/John

[tawauboy]

you can inject co2 into the sump pump inlet.
the impeller will break up the co2.
and co2 has quite a fair bit of time for disolution along the return pipe.

[BFG]

I agree. The output tube can be connected to a vertical rainbar to provide more even distribution of co2 into the main tank.

[Johnc]

Yes, that would indeed be a better idea... if there is a way to do that for the pump you are using. If not, bring the CO2 inlet to as near to the pump outlet as possible. The strong outflow from the pump will also break up CO2.

[bossteck]

Dear all,

Thank you all for your great advice and sharing your experience.
Have a Happy CNY!

Cheers.

[tawauboy]

Yes, that would indeed be a better idea... if there is a way to do that for the pump you are using. If not, bring the CO2 inlet to as near to the pump outlet as possible. The strong outflow from the pump will also break up CO2.

it will break co2 bubble up.
but injecting to the inlet will yield better result.