I ran my pressurized CO2 directly into the intake of an Eheim Pro II 2026. I did this for close to a decade and then sold the co2 system. It is not the best idea to push gas into what is essentially a pump. It can cause cavitation.
What causes cavitation in a pump?
Cavitation happens when bubbles, or voids, form within a fluid because the pressure quickly drops below the vapor pressure. When the bubbles experience higher pressures they collapse, creating small shockwaves that, over time, damage parts.
In the case of pushing CO2 through the canister, one is inducing gas bubbles rather than their being formed because of pressure differences at the impeller. Unless one has a high quality canister, pushing CO2 bubbles through one will damage it and ultimately result in failure. For this reason in 2002/03 the only canister I was willing to try this with were Eheims.
I ran this set-up for for almost 10 years. I still have that filter running but without CO2 involved. I dod this because I had no place to inside or outside of a tank to put any sort of diffuser. Also, I ran a somewhat lean bubble rate a about 1 bpm. However the system ran 24/7.
Also, I hate ovverpaying for stuff and mos of the "sophisticated" plants stuff is greatly overpriced and usually not needed, imo. I wont use expensive substrates mulm is cheap but takes time. I did not use a pH controller or solenoid either.
And my Eheim is easy to prime since I only have to do it once and I am set after that. The Eheim has a connection system which close the intake and return at the filter end of the intake and return. Once the filter is in use, to do maint. one closes the valve which leaves both hose filled with water. After I clean the filter, I refill it with water before I return it to the tank. Reconnecting the hoses also opens the closed ball valves and, viola, its ready to restart without having to using the big priming button.
I have 3 of these running on different tanks plus one on the shelf for spare parts as the filter is long discontinued. I also have a NIB 2028 which is a bigger model- it has 3 baskets instead of 2.
I cannot say anything about the quality of Oase but when I was shopping for the canister to use with the CO2, I refused to buy Fluval or anything else not Eheim. In fact I got a used Fluval which came with a used 75 gal. tank I purchased. I sold the running Fluval and it's media for $25 and then bought another Eheim 2026 in it's place.
In looking at the Oase site and how the set-up their filters, i would not use one. Or at least not using their media. I have one of my Eheim 2026 loaded 100% with Poret foam. It is all 20 ppi. My canister pre-filters are the ATI ones with their coarse sponge. The higher ppis that Oase uses will simply clog way to fast. In the six plus years I have had this one canister filled with Poret it has only needed to be cleaned twice. I know it is time when the return slows. The first time was over 3 years after i set it up.
My other canisters which use an assortment of media, including the Eheim stuff, are cleaned twice a year. I do have a couple of 30 ppi Poret cubefilters but most of them are 20 ppi, the same applies to all my Mattenfilters.
If i ever put the 2028 into use i would fill the first of the three baskets with 10 ppi Poret foam and the other two with 20 ppi.
As always this is how I do things and this doesn't mean other ways or canister brands are not decent. But I tend to standardize my equipment since i have so many tanks. All my hang-ons are AquaClears, all my canisters of Eheim pro IIs and almsot all of my air powered filters are Poret foam. This makes it simpler when it comes to having spare parts on hand,
Finally, the Eheim Pro II came in two models. One comes with an internal heater. I will never use a filter which has a built-in heater. If it fails full o, that can do a lot of damage. Also, I would rather use that space to hold more media. Again, this is my personal preference. Of all the equipment we use, heaters have the highest fail rate. And when they fail full on you can lose a lof of fish and plants if you do not catch this in time. On those of my tanks filled with expensive plecos I use a heater controller. I have all the same model on 11 tanks. This lets me use multiple heaters on a tank.
Coincidentally, bothe Oase and Eheim were founded in 1949 in Germany, I was founded a year earlier in New York ?
