Flow meter

[gjcarew]

If I were you, I would try to set aside a day to monitor your CO2 throughout the day. Time it with like… laundry day or something. Start by figuring out what your baseline pH is after letting your tank water sit out for at least a couple of days. Then, check your pH every half hour or so. If it doesn’t hit a plateau and stabilize there throughout the day, you need more surface agitation. Realistically, you should be getting your 1+ pt drop by the time the lights come on, and maintaining that level throughout the day. Here is a pH chart from my tank..


View attachment 1540

From the limited info here, I’m guessing that you’re not offgassing as much as you think. I'm saying this because of the bolded part of your statement above...

Check out this article from 2hr Aquarist for some more insight…

Surface agitation in CO2 injected planted tanks - The 2Hr Aquarist

I could definitely be doing more for surface agitation, but this tank is also in the guest bedroom so it has to be silent. Unfortunately, surface agitation also tends to be a bit noisy, hence using a surface skimmer instead of an airstone. I'll need to get out my pH probe and recalibrate, but this sounds like a worthwhile endeavor.

 

[Jellopuddinpop]

I could definitely be doing more for surface agitation, but this tank is also in the guest bedroom so it has to be silent. Unfortunately, surface agitation also tends to be a bit noisy, hence using a surface skimmer instead of an airstone. I'll need to get out my pH probe and recalibrate, but this sounds like a worthwhile endeavor.

Surface agitation doesn’t need to be noisy or splashing around. All you need is a good, solid ripple across the surface of the tank.

It’s also important that there’s turnover between the lower parts of the tank and the upper part of the tank. This usually isn’t the case as long as your filter inlet is near the bottom of the tank.

 

[Immortal1]

FWIW, on my 75g tank, my RO drum measures 7.2ph with 1dKH (K2CO3 added)(about 24-48 hours after filling).
The drum has a small air stone running in it at all times.
Overnite, the 75g tank will usually get to about 6.9ph before the CO2 kicks on (air stones run most of the nite).
Within 2 hours of the CO2 turning on I am at 6.1ph and within another hour I am at 6.0ph.
Observing the fish, 6.0ph is as low as I will go as a few of them are already spending more time at the surface than usual.

Also, just as a bit more FYI - I run my Flow Meter at 8 and the tube is under 20psi (metering valve on the output). So, according to some accurate bench testing, that equates to 35.1 sccm of CO2

 

[GreggZ]

I've seen a lot of people saying they run 20-30 cc/min on a 75 gallon, but I run 10 cc/min and that's about all I can get without the fish gasping by the end of the photoperiod. At 15 cc/min they start gasping fairly quickly. I think my aeration should be alright, I have good flow and run a surface skimmer 24/7. I have the RMA-151-SSV so I don't know what is so different about my setup that it seems to sip CO2.

This is interesting.

What size CO2 tank and how long does it typically last on your 75??

How may hours a day is it running?

 

[Jellopuddinpop]

Alrighty, so I just got myself a Dwyer flow meter after reading through this thread. I seem to be having a problem though, and the flow is bouncing all over the place (between like 40 and 60 ccpm). Where should I start with trouble shooting this? Check Valve, (more thorough) leak check? Needle Valve?

I'm feeding a reactor, so the only pressure on the system is before the needle valve.

 

[Immortal1]

Alrighty, so I just got myself a Dwyer flow meter after reading through this thread. I seem to be having a problem though, and the flow is bouncing all over the place (between like 40 and 60 ccpm). Where should I start with trouble shooting this? Check Valve, (more thorough) leak check? Needle Valve?

I'm feeding a reactor, so the only pressure on the system is before the needle valve.

What are you running for a canister filter / return pump?
I am asking - trying to figure out what is feeding the reactor.
What is your regulator pressure set at?
For me, I could see minor fluctuations in the flow meter when the bubble in the flow meter was at the same pressure as the reactor water.
Once I put the bubble in the flow meter under regulator pressure, the bubble was rock steady.
A simple test for you would be to turn the flow meter upside down and basically run it backwards which would put the adjusting valve on the output side of the co2 flow. Obviously the scale would not be accurate, but it should be a real simple way to verify that this works.

Also, I assume you have a check valve of some sorts between the flow meter and the reactor? I have had a check valve go bad in the past and got some water in the flow meter. The wet bubble got stuck in the tube and would not work correctly until I cleaned the tube out with a can of compressed air.

 

[Jellopuddinpop]

What are you running for a canister filter / return pump?
I am asking - trying to figure out what is feeding the reactor.
What is your regulator pressure set at?
For me, I could see minor fluctuations in the flow meter when the bubble in the flow meter was at the same pressure as the reactor water.
Once I put the bubble in the flow meter under regulator pressure, the bubble was rock steady.
A simple test for you would be to turn the flow meter upside down and basically run it backwards which would put the adjusting valve on the output side of the co2 flow. Obviously the scale would not be accurate, but it should be a real simple way to verify that this works.

Also, I assume you have a check valve of some sorts between the flow meter and the reactor? I have had a check valve go bad in the past and got some water in the flow meter. The wet bubble got stuck in the tube and would not work correctly until I cleaned the tube out with a can of compressed air.

The reactor is powered by an Oase Biomaster Thermo 850.

The regulator is set to 20lbs.

There is a check valve in between the flow meter and the reactor, and I'm confident that it's not faulty (leaking water backwards) because when I took the bubble counter out, it would have fed water back all over the floor if water was getting by.

Would turning it upside down work, though? I thought that was a tapered tube, so as flow increased, the ball needed to be higher in the tube to allow the air to pass.

I'm wondering if I need to get a higher quality check valve with a lower cracking pressure. It almost looks like a visual representation of the check valve opening and closing. Whenever the valve opens, the co2 rushes through and the meter jumps up. Then when pressure is relieved, the valve closes, the meter falls, and pressure rises. Rinse and repeat...

 

[Jellopuddinpop]

Alright, forget I even brought it up, lol. I went downstairs to video the jumping meter, and it's rock solid now. I guess it just took some time to balance itself out

 

[Immortal1]

Alright, forget I even brought it up, lol. I went downstairs to video the jumping meter, and it's rock solid now. I guess it just took some time to balance itself out

Interesting. I do like your idea of a different check valve with a lower cracking pressure but I just can't imagine a check valve having anything close to a 20psi cracking pressure.
Just for an FYI, I actually have 2 check valves between the reactor and the flow meter. If I see water between the 2 check valves I replace both.

 

[*Ci*]

Alright, forget I even brought it up, lol. I went downstairs to video the jumping meter, and it's rock solid now. I guess it just took some time to balance itself out

Oh, good … I have two Dwyer flow meters on order and was starting to worry!

 

[Jellopuddinpop]

Interesting. I do like your idea of a different check valve with a lower cracking pressure but I just can't imagine a check valve having anything close to a 20psi cracking pressure.
Just for an FYI, I actually have 2 check valves between the reactor and the flow meter. If I see water between the 2 check valves I replace both.

I like that idea, but I'm using black CO2 tubing. I wouldnt be able to see any water regardless. Also, this tubing is BRUTAL to get off of any barbed fitting, so I do my best to try not to take it apart.

 

[*Ci*]

Basic question:
On the Dwyer RMA 151 ssv, the input of co2 goes on the bottom and the output to the aquarium goes out the top of the flow meter, correct?
It doesn’t actually say anywhere on the meter or in the manual, so I just want to make sure I’m setting them up right.

 

[GreggZ]

Basic question:
On the Dwyer RMA 151 ssv, the input of co2 goes on the bottom and the output to the aquarium goes out the top of the flow meter, correct?
It doesn’t actually say anywhere on the meter or in the manual, so I just want to make sure I’m setting them up right.

Yes you have it right. The flow goes from the lower input to the higher output.