Help Starting co2 on my 90 gallon with 2 canister filters

[1_Blake]

Hi Everybody,

My co2 equipment is arriving today from co2 art and I was looking to see if you had any advice on placement of the inline diffuser. My tank has 2 canister filters, a Fluval 406 and 306 arranged as shown in my poorly drawn diagram. The problem (or hopefully lack thereof!) is that from what I've read simply using a splitter on a co2 line will be completely useless because the co2 will take the path of least resistance and it will flow though the diffuser that is less obstructed leaving the other non functional. My question boils down to will it be fine to just have the diffuser on one canister filter and allow the dissolved co2 to spread throughout the tank based on natural circulation of the water? To add to this I also use an inline heater rather than an in tank heater, would I be better served with the heater on the higher flow 406 and the co2 on the slower 306 or vice versa?

 

[1_Blake]

Just realized my picture didnt attach showing the positions of inflows and outflows... should be on this one!

 

[Koan]

will it be fine to just have the diffuser on one canister filter and allow the dissolved co2 to spread throughout the tank based on natural circulation of the water

Yes the CO2 gas dissolved in the water will be equilibrating throughout all of the water circulating in your tank, so the injection point in that circulation doesn't matter

What does matter is
1) the amount of flow of that circulating water, around all of the plants and hardscape in your tank, to distribute that CO2 to each of your plants , and

2) the amount of surface agitation you have, to adequately offgas that CO2 in order to reach your equilibration point early in the plants daily growth cycle.

Here are some detailed discussions by one of our members here @Dennis Wong

How to set up a CO2 system for the first time

Setting up CO2 system for the first time? This is a beginner's guide to setting up a CO2 system for the first time. Includes a checklist of all necessary parts and the pitfalls to watch out for when setting up a CO2 system.

www.2hraquarist.com

Gasping fish does not automatically mean that your plants are receiving good CO2 levels

Having gasping fish is not a good indicator of optimal CO2 saturation. A tank can have gasping fish and poor CO2 levels at the same time. This page explores why some tanks suffer from such a situation and what one can do to optimize CO2 levels without stressing livestock.

www.2hraquarist.com