# [Wet Thumb Forum]-Flow rate for CO2 reactor



## Bob Hooper (Apr 10, 2004)

I tried posting this question over at the DIY forum but didn't get any replies so I thought I would try here.
I recently built a DIY reactor (Ghazanfar Ghori's) I wanted to power it with a pump dedicated soley for the reactor.I wanted to use a Rio 180 but the flow rate is only 120 GPH. What is the minimum flow rate I would need to make the reactor work effectively? Is it possible to have too much flow through the reactor?
Thanks,
Hoop


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## Bob Hooper (Apr 10, 2004)

I tried posting this question over at the DIY forum but didn't get any replies so I thought I would try here.
I recently built a DIY reactor (Ghazanfar Ghori's) I wanted to power it with a pump dedicated soley for the reactor.I wanted to use a Rio 180 but the flow rate is only 120 GPH. What is the minimum flow rate I would need to make the reactor work effectively? Is it possible to have too much flow through the reactor?
Thanks,
Hoop


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## Jon Mulzer (Mar 9, 2003)

Well, I don't think you can have too much flow until it is so powerful that it pushes the bubbles straight out the bottom. 120gph I would think would be enough flow, but it all depends on the size of your tank and how much CO2 you plan to run through it. CO2 is VERY soluble in water and I am getting 100% dissolution on my tank with only 145 gph powering it. So you should be fine.

Might help if you gave us some more details on your question though.


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## Bob Hooper (Apr 10, 2004)

This is my 1st try at pressurized co2 system so please bear with me.I want to run 3 small tanks off of the same co2 cylinder, I have a 20 gal long and a 29 gal. both have aqua clear filters on them. The 3rd tank is a 38 gal but has a canister filter. I want to use an external reactor for each tank and want to power the reactors for the 2 smaller tanks from separate pumps.I intend to use the canister filter to power the reactor for the 38 gal. Will the Rio 180 pumps (rated at 120 GPH) provide enough flow to the reactors for the 2 smaller tanks? I'm not sure what you mean by "more details on your question"
Thanks,
Hoop


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## JamesHoftiezer (Feb 2, 2003)

120gph might work with small reactors, but not if you use large diameter reactors of if there is a lot of resistance in the hose set up. THe key is too keep the flow inside the reactor high enough to keep teh water agitated.

The details being requested involve several things which we might assume, but might do so incorrectly. You are planning on using the pumps inside the tanks(as opposed to sumps), that the reactor will be directly behind the tank (as opposed to underneath in a cabinet) and the reactors will be sized for the tanks (as opposed to monsters for 200g tanks). That kind of thing.

*James Hoftiezer

Tank Journal - Aquascape ( Latest / Archive )
Tank Journal - Parts and Construction ( Latest / Archive )*


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## imported_Platy (Feb 4, 2003)

My Reactor *based on Hoftiezer's post in the DIY section* would not run on my Magnum 350 's return flow, it simply didnt move enough water. So I used a Rio 1100 which worked better, until I finally got a inline pump *didnt want the clutter in the tank* that is 1400 gallons an hour. I put in an inline valve to slow down the flow just a little for the uv steralizer, however with the 1400 gallons I get no air pockets and 100% dissolve with no waste. The reactor is just over a foot long so I dont loose bubbles through the bottom either.

Hope that helps

Good Luck

ImaNewbie -
125 Gal - 3.07wpg - 99% flourite - Pressurized Co2 - Uv Sterilization when needed - Densly Planted


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## JamesHoftiezer (Feb 2, 2003)

Platy,
Flow seems awesome for a reactor as long as you're not shooting the bubbles out the end









For the UV be careful. Most have a max gph around 300. More than that and you're wasting the UV. A sterilizer needs a minimum amount of time in contact with the water. The faster the pump the shorter the dwell time.

*James Hoftiezer

Tank Journal - Aquascape ( Latest / Archive )
Tank Journal - Parts and Construction ( Latest / Archive )*


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## skids (Mar 23, 2004)

I have a similar problem. I made a reactor with 2" PVC throughout for a 75 long tank. The CO2 is a 5lb bottle, with JBJ reg, solenoid and bubble counter. A tetra check valve is on the blue CO2 proof silcon airline hose just about 5" from the entry to the reactor. I have this on the outflow from a Renaissance Prime 30 (by Hydor, aka the Proquatics 2400) it gives about 1500 gph to the reactor. However even with the CO2 turned way up the gas cannot overcome the pressure against the water to enter the reactor. I turned down the flow rate to where it would but then the cannister filter is barely trickling. I let it sit to build up gas pressure but that didn't help. 

The only variations I made were making mine way longer than I needed 20" in the main 2" section includeing 2" Tee joint, and so it is packed with about 12 or so large bioballs. Maybe that is too much internal resistance? My JBJ reg is factory preset at 50 lbs/ in2. The tubing is really stiff so it is pressurized. 

I'm going to try to run it off my output from my UV sterilizer which has it's own Rio600. Maybe that will prevent water from holding the gas back?


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## skids (Mar 23, 2004)

Two corrections, the cannister filter runs at 300 gph not 1500. Also the JBJ runs at 40 lb/in2 when going (it showed 50 when off). I tried to tilt it upside down to kick start it, that didn't help.


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## Aqua Dave (Mar 16, 2004)

300gph shouldn't produce too much pressure for your CO2 to get into the reactor. I'm using a MagDrive 5 in-line pump that is giving me around 300 gph in my config and I don't have any issues. My reactor is built exactly according to James' plans with the 2" pipe. I have it stuffed with as many bio balls as I could fit. I'm using one of the german air systems check valves and that has not presented any problems. My regulator is set at only about 15psi. So something is either not working right or hooked up wrong. Have you tried running the CO2 without the check valve to see if that's the problem?

I had a problem with the CO2 not getting completely disolved and wound up putting some filter sponge at the bottom of the reactor. I seem to be getting much better absorption now. I'll just have to take the sponge out every month or so to clean it.

David


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## skids (Mar 23, 2004)

Thanks, I swithced to the Rio 600 and that helped. Then I read your post and ditched the check valve and shortened the tubing to under 10 inches. It is now running at a lower flow rate ok, I still can't do 1-2 bubbles/sec but that may not matter. It's at 3.3 bub/sec which seems to be the minimum to prevent backflow. My CO2 is now 25ppm so it's working. When it was not working it was 5ppm. So it's all good. The pH went from 7.6 down to 7.0 once I switched stuff around, and the plants are pearling w/i 3 hours of the lights coming on, so I have common sense feedback that it's working, not based on Hagen's dropper kits.


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## Avi (Apr 7, 2004)

You *can't* rely solely on the pump's gph rating. Remember that whatever pump you use, there's going to be some (probably significant) loss of flow rate due to "head" if the pump is below the tank or even if there are plumbing elbows between the pump and the reactor or pump and tank. Take a look at the pump's rating at, for example, 3 or 4 feet of "head", if it's posted on the manufacturer's website. If it isn't, you have to kind of guesstimate how many gph are lost die to the pump having to drive the water a distance to the tank and back...it is significant so you should look into that in deciding whether or not a pump is ample for your needs.


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## skids (Mar 23, 2004)

Yes, the figure I posted was based on the manufacturer max flow expected. The expected flow at the total elevation it must climb varies. (40"/~ 1 meter) The Rio600 has around 60 gph at 3 feet. The Prime30 (Proquatics 2400) has 240-300 gph max rated so around 120 gph expected. 

That doesn't change the issue that there was too much backpressure from the water for the gas to enter. The Rio600 is now working better.


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