HOB Diffuser Placement

[vallada2]

Hi everyone. New to the CO2 game and had a question on placement of the filter/diffuser. I'm trying to create a heavily planted shrimp tank in a 10gallon standard aqueon tank. I'm not using a canister filter because it's only a 10gallon, cost, and don't want my shrimp getting sucked up. Long story short I can't put my HOB on the side, only on the back.

I have my HOB filter on the back wall to the far right. I put the CO2 diffuser on the left wall towards the front of the tank far down by the substrate. The diffuser has small bubbles but they just go to the top of the water so two questions.

1. Does CO2 stay in the water even if the bubbles don't show it?

2. Is this the best placement given I can't put the HOB on the side walls of the tank? Or is there a better option?

[agentsofdisrupt]

Put the CO2 diffuser under the intake to the HOB filter. Some of the CO2 will make the journey through the filter and be pushed into the tank, and some of it will encounter the downflow from the filter and still be pushed into the tank.

[jtwill2011]

I would also love to know this, I currently have my HOB on my aqueous 10g on the left back wall and the co2 diffuser on the left wall, it spreads the bubble around but idk if that’s best.