[AshJRenee]

I’ll try to make this as short and sweet as possible...

29g tank, fully cycled
Marineland Penguin Filter rated for 50g, “hot rodded”
Fluval Planted 3.0 light

Around a month ago I set up a new 5b CO2 tank with co2art’s Pro SE Dual Regulator, drop checker, diffuser, the works. I’ve been running into difficulty getting my drop checker to the right color, in the right amount of time.

I run my CO2 2hours before the lights turn on, it goes off 2 hours before my lights go off because it takes forever to reach “light green.” I’ve moved my diffuser twice, right now it’s currently right under my HOB. I also have a circulator right above it to disperse the bubbles across my tank.

5 hours of running my CO2 at 2-3 bubbles per second, this is what my drop checker looks like:

I just moved this drop checker down last night to try to get a more accurate reading. At this rate I don’t see it hitting lime green today, so even though I’ve had CO2 in this tank for almost a month, I’ve not been anywhere near 30ppm.

... Please advise. I’m completely stumped and I don’t know what else to try.

 

[x0769]

I'm commenting because I also have a HOB, and want to start CO2. All the youtube videos I've seen have a canister filter with CO2. Hopefully more people chime in with their experiences. Good Luck!

 

[Bettatail]

get a sunsun canister filter, ...

or

Too much surface aeration with HOB filter, or you have to settle with less than 30 ppm co2 in the tank, 2-4 bubbles per second you will be ok, even a 5 ppm increase of co2 in the water you will see noticeable plant growth, the key is to keep the co2 injection steady.
and,
Place the diffuser at right place so most of the co2 mist go with the current that towards where most plants are, the co2 concentration is high in this current but low after dissipation elsewhere in the tank.

 

[AshJRenee]

The 2hr aquarist recommends a certain level of surface aeration, I already removed both of my bubble bars and my water level is flush with the filter outflow... Is there no way of achieving 30ppm CO2 without a canister?

Surface agitation & gaseous exchange in CO2 injected tanks

Surface agitation in a planted aquarium - yes or not ? This page explores why having some surface agitation and turnover is actually useful in planted tanks and actually makes tuning CO2 to optimal levels more easy.

www.2hraquarist.com

 

[marex]

I have a HOB on each of the tanks I’m using pressurized CO2 in. They are not the most ideal filter types to use with pressurized CO2 but it has worked for me. It takes a while for my CO2 level to build up but I do get pearling. It takes about 2 hours for my drop checkers to turn a dark green after my CO2 comes on and by the end of the day they are almost yellow, which is about 5 hours after.

I run my 7 gallon tanks at about 1bps and my 10 at around 2bps. 2 of my diffusers sit right below the hob as well. You might want to check if you have any leaks in your system.

There is also a guy on etsy that sells baffles for hob filters that can help with the turbulence caused by them. Here’s the link: Aquarium Filter Baffles 3D Printed ABS Plastic Pet Safe | Etsy

 

[moke]

well, drop checkers tell you what your co2 levels were 2-3 hours prior. get a pH pen and use it to give you real-time estimation of co2. you want to see a 1pt drop in pH by the time lights come on and keep it steady until you turn off co2. you achieve this by increasing surface agitation. running an HOB should give you good surface agitation. this fills in the details.

 

[AshJRenee]

My pH has only dropped .4 in almost 7 hours, it definitely didn’t drop a full point before the lights came on. I don’t know how else to optimize this setup and I don’t have the space for a canister right now.

 

[Tiger15]

Plants need good water movement to evenly distribute CO2 and nutrients. HOBs provide excellent surface skimming and back to front flow, so I suggest placing your circulation pump at the long end to cross over the back to front flow. As shown in the pic, I run 3 Penguin 350 HOBs in my 125g high tech with a 700 gph circulation on the left end, and a Tunze CO2 reactor at the center to dispense CO2. Tunze is self driven by a powerhead and is more efficient than ceramic diffuser. I prefer HOB to canister because it is easier to clean and is leak proof.

 

[dawktah2]

I have a small tank but using CO2, diffuser is right below the HOB (Tidal 35). I get pearling from the plants and our pH drops. As recommended get a pH pen or small waterproof pH checker. I had to turn the bubble count down, when I started, way before drop checker turned green. Green, yellowish green, check by using pH.

 

[AshJRenee]

Plants need good water movement to evenly distribute CO2 and nutrients. HOBs provide excellent surface skimming and back to front flow, so I suggest placing your circulation pump at the long end to cross over the back to front flow. As shown in the pic, I run 3 Penguin 350 HOBs in my 125g high tech with a 700 gph circulation on the left end, and a Tunze CO2 reactor at the center to dispense CO2. Tunze is self driven by a powerhead and is more efficient than ceramic diffuser. I prefer HOB to canister because it is easier to clean and is leak proof.

Before I put this circulation pump in, my CO2 diffuser bubbles were just going straight up, despite being right under the HOB they weren’t catching the current. If I move the circulator to the long end of the tank, should I move my CO2 line as well, or should it not matter if the tank has optimal circulation? Beautiful set-up!

 

[Tiger15]

Under high water level, the circulation of a hob is to push surface water toward the front, sink on the front and return bottom water up the back. Placing the diffuser right below the hob is to get lift from the rising water. However, the circulation pattern will change with dropping water level and the best way to find out is to drop some fish food to visualize the circulation. I would relocate the diffuser to the opposite front side of the hob or on the opposite end of the circulation pump where water is sinking. The goal is to distribute the micro bubbles throughout the tank volume rather than rising up rapidly to the surface. You cannot eliminate bubbling with ceramic diffuser unless you switch to a CO2 reactor.

 

[moke]

My pH has only dropped .4 in almost 7 hours, it definitely didn’t drop a full point before the lights came on. I don’t know how else to optimize this setup and I don’t have the space for a canister right now.

agree with @Bettatail. you may have too much surface agitation. check out the water movement in the impeller well--probably where you're losing a lot of your co2. @Tiger15's suggestions are spot on. optimizing co2 levels takes time and patience. please check out the link in my first post.

 

[Aaronious]

Before I put this circulation pump in, my CO2 diffuser bubbles were just going straight up, despite being right under the HOB they weren’t catching the current. If I move the circulator to the long end of the tank, should I move my CO2 line as well, or should it not matter if the tank has optimal circulation? Beautiful set-up!

In my 75 run the difuser as low as possible and under my spray bar. this way they head up to the current created by the spray bar. I only set my co2 up to the point the bubble collect on the surface and all plants grow fine, If they aren't it's because of light. Then I trim or move something and it grows wonderfully. So getting that 30ppm or the 1.0 PH drop isn't that important. I guess I also don't know what your goals are. But I just want healthy plants and environment for the fish. healthy plants will produce more and then one day I will have to move some but that's for another day.

I know longer monitor CO2 other than just visually looking at the bubbles coming out of the difuser.

 

[Tiger15]

agree with @Bettatail. you may have too much surface agitation. check out the water movement in the impeller well--probably where you're losing a lot of your co2. @Tiger15's suggestions are spot on. optimizing co2 levels takes time and patience. please check out the link in my first post.

What he has is a Penguin 200, not too strong for a 29g. I am running one in my 30g. But his placement of the diffuser right next to the strainer is in the wrong place, allowing some bubbles suck into the hob, and others lift by the up current. The placement of the circulation pump next to the hob in the same direction will push even stronger front to back circulation.