I built a griggs reactor for my sump and im not sure why it doesnt work. could it be because my pump i bought not strong enough? its a lifegard 320gph pump. The reactor is around 24" tall and 2" in diameter.
it just fills up with air. is it too long? do i need to move the air hole down? what do i need to do to not have wasted ~$100 lol
I don't think you need a bigger water pump - that is not the problem. I have built a 6"x 30" CO2 absorber column and have had it running for 3+ years with a 200 gph pump. This services about 100 gallons.
There are a couple of things going on...
1. When you use atmospheric air - its mostly nitrogen and oxygen that have poor solubility in water so the air simply accumulates. When you inject CO2 the water will absorb it and the water level in the column should go up as the gas enters the water. If you have some atmospheric air left in the column it can take as many a few days for it to be fully absorbed and ejected from the column.
2. No backpressure - if you add a little bit of backpressure on the discharge by throttling the outlet valve it will pressurize very slightly the air in the column and increase its absorption rate. This will speed up the kinetics and allow you to inject larger volumes of CO2 into the tank. Of course now, you can easily gas all the fish to death but that can be handled by carefully dialing in the right gas flow rate.
i moved the inlet down. i hooked it up to real co2, i think ill still get air pockets over time... not sure what to do. if i close the valve it just stops pumping. maybe these pumps just are terrible with head pressure or something. I think it may work but im unsure
There's no good reason for those bubbles to be moving up, against the flow of water, unless that pump is gimpy or flow is badly throttled somewhere. Does the outflow look like there's plenty of flow? You might check by filling a couple 5g buckets (although a standard 5g bucket is actually more like 6g). After doing the math, the fill rate won't be anything near the rated pump flow, but it should be, at the very least, half, and likely much better than that.
All that being said, that size reactor most likely won't be anywhere near what you'd need for a 180g tank. But you need to get things sorted before you worry about that.
you dont think in a sump that would be good enough? i know people use regular defusers so why wouldnt this work? its as big as i can fit under my stand in the sump.
So i ran it all night with co2 at ~4-5 bps and it never filled up i had a venturi of bubbles a the top breaking down. I wonder if my pumps just a turd, it doesnt really seem to be a great pump
From that video, you definitely need more flow. You're also going to be trying to push like probably at least 15 bps to start, maybe a lot more. I have a 90p with a large sump and I use about 10bps. Basically you'll need a lot of CO2, probably dual reactors that size.
well i ran 10 bps all night and it didnt just fill up with air at all. i think its actually working pretty well i see the bubbles spin into smaller bubbles in a tornado all the way down. I dont care how long it takes to get it to the amount i want since ill run it 24/7 on a ph controller.
Hey - it looks like its working as its supposed to. If there is no visible gas pocket that confirms the CO2 is being absorbed into the water. Time to hook it to your tank setup and let it go. Please make sure you have a drop checker so you can adjust the CO2 rate upto the light green color in the checker.
Just a thought on your Griggs setup. With the way you have the water entering the chamber, the water speed slows down drastically then makes a slow turn down to pick up the bubbles. The suggested mod below likely will give you better results on your test rig.
Quick question: Is this setup just going to be sitting inside the sump itself? Or are you planning on using this as your main return pump back to your 180?
I was just thinking, if you are going to be buying a much larger return pump then could you have this setup outside of the sump between the return pump and your return outlets in the tank?
Its going to be in the last sump chamber with the heater and then it flows through a bubble trap. I think the flow ended up being enough and the air i was putting too it was just too much. I thought about doing this, but i didnt want to tee it off anymore than i already did. Im running a vectra m1 and wish i went with the larger pump but oh well.
It's because you have a huge elbow in the top of it which is an easy place for an air pocket to gather.
You want something like this where the flow goes directly down into the pipe. This way air cannot form a pocket in the corner, it tries to travel directly back up the tube but the flow smashes it back down.
IMO this design is the only way to go. Have the tube round right into the top of the griggs and point vertically downwards. No elbows or anything like that at the top/point of entry. No chance of air buildup.
Mine is similar to this but MUCH larger and has a big elbow at the bottom, works flawlessly.
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