Obviously this is THE board for discussing this topic. Given all the folks who work very hard to insure that their tanks have good CO2 dispersion, I'm hopeful that I can get some feedback on what I have today and what I think I am going to do.
I have 58G tank, planted pretty heavily. It's been up and running for 4 years or so. Lighting is 2x39W HOT5 plus a 22W T5. Doing EI with 50% water changes every 14 days. Subtrate is Flourite. Water is hard, kH is high. Using pressuring CO2 w/ a pH meter to keep my CO2 levels stable and avoid repeating the nightmare end of tank dump I've experienced before. Only run CO2 during the day. I'm diffusing it by letting it get sucked into the input into my Eheim 2026 canister. It makes some noise as it chops, and only very small bubbles seem to come out of the spray bar, so it appears that much of the CO2 is dissolved before it enters the tank.
My big compliant/problem is that many of the plants I try to grow die off. Even rotalias, ludwigias, and some other "easy" plants wither and die off. Some grow, but most do not. I suspect that there are three possible answers:
1) Light isn't high enough. I'm not sure this is the problem. I know it's tough to use the WPG calculations with HOT5s and T5s. My gut is that this is plenty of light to grow the simple plants that I am having trouble with.
2) EI has been too low. It is possible I've been dosing too low. so I've recently upped some of those amounts. This is a pretty easy one to experiment with since the biweekly water changes reset things if something is out of whack.
3) CO2 Dispersion - Personally I'm wondering if this is the REAL problem that I'm facing. As mentioned above, I'm using the 2026 to chop, and then I use an Eheim spray bar. It's mounted front to back on the short side of the tank just under the water level, with the spray going right to left. The back section of the bar points straight across the surface with just a bit of ripple, the middle section down at a 45 degree angle, and the piece near the front pointing down the right tank wall.
That is the only circulation I have right now, and I'm not convinced it's enough. I was considering thinking of putting a Rio or Mini Jet on the back rear and blowing across the water, and then using that as a mister. But I really hate the vortex effect and don't want too much flow. Also, it appears the CO2 chopping is working pretty good as it, and it doesn't create a mist effect.
So, here was my idea ------- I was considering sticking with the Eheim chopping method. and trying to up the flow with a Koralia 1. It sounds like they move water without the jet motion. I'm thinking that would help get the CO2 enriched H2o from the spray bar better circulated around the tank.
As an alternative I was considering a small Rio and switching to the misting idea, and then I get both the mist and the additional circulation.
I take it the MiniJet can't support the needlewheel mod, right? If so, how do you open it besides using a hammer???? I have one of those in my spare equipment box and could give that a try if it might work.
IF anybody has any suggestions or ideas I would really love to hear them. I'm open to anything. It seems like I'm trying to do the right things, it's just the results aren't what I would expect.
Thanks in advance for your advice!!!!