Originally Posted by Dave-H
I am glad to see this comment, because it's hard to digest the message that algae issues can be resolved largely by having good CO2 levels/flow/etc - it's just not true in all cases.
I've yet to see otherwise in 20 years.
On my tank, I had my CO2 running steady 24/7 with massive flow and a high enough levels to kill off some fish and all the invertebrates - a bright yellow DC! That was a clean restart of the entire tank, and included some aggressive Excel use and constant pruning etc. The BBA came back and took over the tank within a couple of months.
You can gas the fish with poor O2 and low CO2.
Does not imply there was ample CO2 for the plants, or that other factors were not accounted for.
To get a reference tank, you must have mastery of the control in any test, otherwise you have no methods comparison. A tank without BBA being an issue is a reference tank.
Running CO2 24/7 means you add more stress to the livestock than adding it only during the light period. There's no good reason to do this, timers are 5$.
Adding CO2 only when the plants are growing (during the light cycle) means the plants will add more O2, so you have more buffer/wiggle room with CO2.
Drop checkers are not the best method to measure, gauge CO2.
I have several tanks and the CO2 ppm is all over the place.
I made CO2 reference solutions to check as well as KH reference solutions.
I also measured O2 and changed all my filters over that produced 1-2 ppm higher O2. Cooler temps also make it easier to keep O2 higher and slows plant growth. Which makes adding CO2 even easier.
Even my 180 which is about 83-84F, has 70 ppm of CO2 after 1-2 hours.
Amano shrimp likely help, SAE's definitely help.
When starting a new tank, I do more water changes and care till things grow in. for some client's, I'm only able to do this once a week. So they might get a little algae in the start up phase. But I knock it back and then a couple of weeks later, things are fine. If the tank is at home, then I can take better care of things in the new tank start up.
I think given your goal, you should stick with it.
If the CO2 algae thing is a real monkey on your back, it'll be waiting for you to master it. A lot of folks have to beat this thing. Even if your goal is different
Just the way some of us are.
Client tanks are very instructional for myself, they illustrate what goes wrong even with good care when the CO2 tank runs out mid week. How plants and algae respond. Corrective measures to fix things thereafter.
I think you'd be best off adding CO2 to the low light tank given your goal. You would end up with maybe 3-4x the growth rate and be able to keep most all plant species together.