DIY CO2 combo w/ HOB filter questions?

[duy]

So I know that these questions have been asked to death from various forums throughout the net, but I have been reading mixed recommendations and they're not really helping. If anyone has any experiences and tips, please chime in. Every opinions/thoughts are valued!

The tank in questions is a 10gal, moderate-highly planted, NPT tank.

I want to add a DIY system to this tank due to algae problems pointing towards low CO2, however there are some concerns.

1. In order to keep the HOB from gassing out the injected CO2 and rendering my efforts useless, I have to reduce surface agitation. However, surface agitation is the only thing keeping biofilm from re-appearing, which I do not want. How should I remedy this problem?

2. I'm afraid the HOB may cause flunctuations in CO2 levels, which I have read that will cause algae outbreak (which I want to avoid). Is this fear rational?

3. NPT doesn't primarily depend on a HOB for filtration, merely water movement. Can I just remove the filter and just inject CO2 ( Or turn the HOB's output to a minimum ) ?

4. Should I just dose Excel instead and save myself the headache and efforts to run a DIY CO2 system if the result will be unstable? (I have riccia in the tank and I read that riccia does not respond well to Excel, however it would be a problem if I dose a minimum amount, correct?)

[DarkCobra]

As long as the water level remains fairly constant, so will the surface agitation from the HOB; and fluctuations are avoided. If water evaporates quickly, top offs every couple of days may be needed.

Any amount of CO2 loss from surface agitation can be compensated for, simply by adding enough extra CO2 to replace what is lost. Even on my 10G with two HOBs, it doesn't require an unreasonable amount.

The rest is out of my field of experience (NPTs and Riccia/Excel), so I'll leave those to others.

[duy]

Thanks for the input, I feel more confident about making a DIY system now ^^. Will start ASAP