DIY Co2 (again)

decreasing bubbles -- or now you see it, now you see it

The geometry of the bubble tells us that if the diameter is reduced so that it is now only 25% of the original, the volume is reduced to the cube of that, or 1.56% of the original.

When you are using the Hagen generator, the bubble begins smaller than a DIY bubble and reduces in size visibly as it travels. When you use a DIY the bubble is bigger and the reduction in size is not as visible. Often there is a sizable bubble at the end of the ramp that is wasted.

The Hagen bubble diffuser has a travel path of 60 inches. I suspect that only so many cubic mm of CO2 can be absorbd in that 60 inch travel path. A larger bubble would require a longer travel path in order to duffuse more cubic mm of gas.

But the real quesiton is what sort of CO2 are you getting in your tank? If you are seeing a pH reduction of 0.8 to 1.0, that is about all you need. Use the charts to see that for yourself. While you are there, notice what pH is the border of the danger zone for your water (above 30ppm) and what pH is your target (15 to 25ppm).

If you adjust the chart parameters on Chuck Gadd's downloadable chart you can use the actual increments of pH and KH that you are able to read so the chart can show you how delicate the balance is for your water. It is of no use to show the chart in 0.2 pH increments if you cannot actually measure that and it gives you a false impression of having lots of room to overshoot the CO2 levels. I can only read pH to the nearest 1.0 or 2.0 and kH to the nearest 1.0.

I seem to recall that an Ecco is a canister, right? If so, and you do what you're thinking of, be prepared for a gurgling, splishing nightmare (especially in a bedroom). The co2 hittng, and getting trapped in, the impeller chamber will drive you nuts, and then you may very well wind up choking the impeller with co2, causing it to lose suction and not pump.

You didn't say what size tank you have, but if you really want more CO2, you'll need a trickle-type reactor which can get expensive. I bought one from a friend that he made, and it works wonders, 0% co2 loss in the reactor as long as I don't overjuice the flow rate.

You can make a cheap one by running the output of you Ecco into a cheap gravel cleaner inverted in your tank (the open end of it jammed into the gravel to hold it steady). Run a co2 line under the gravel and up into the gravel cleaner. Water from the Ecco in the top, co2 from the bottom, and a bubble (maybe filling half or more of the gravel cleaner) that the water flows through. CO2 stays in the cleaner until dissolved. Don't pickle your fish with too much CO2. This reactor is cheap, but can be over-effective. It can get ugly too, inside the tank, unless you can hide it.