Sera CO2 reactor problem solved

[johnnypy]

In an effort to minimise the amount of equipment in my 100L cube, I replaced my CO2 diffusor with a Sera 500 CO2 reactor. I added this in the outlet pipework of my Eheim filter which is rated at around 450L/hour. I found that the rotors in the reactor slowed down and stopped almost immediately which resulted in a big build up of gas in the reactor and poor CO2 dissolved in the tank. I took the unit apart and found two issues. Firstly it's possible to push the plastic pipe that the rotors run on too tightly into the lid of the reactor which causes friction. Secondly and more disappointingly, both the rotors had very rough areas from the moulds on their inside surfaces which added a great deal of friction and resistance. The plastic pipe also had a moulding line on both sides. Five minutes with the Dremel, finished off with fine sandpaper and both rotors run fine. I'd bought the Sera unit instead of some of the cheaper copies in the hope of better build quality!

 

[Phil Govier]

Thanks johnnypy for this tip. I also purchased the Sera 500 co2 reactor as a replacement for a JBL ceramic insert "diffuser" that I originally fitted but which I had great concerns over as I had fairly large bubbles appearing in the tank and not a finer mist(or no visible mist at all) I purchased the Sera 500 in an attempt to dissolve more CO2

However, the first sera 500 was returned as when I installed it, it leaked. It took some time to understand that the leak was not from the hose connections but from the join between the main head and remaining body of the reactor. The rubber seal looked ok when disassembled but I also noticed a rough edge on the top of the main body that was breaking the seal against the rubber seal. Obviously their QC in checking these moldings has fallen down.

The replacement sera 500 has arrived just before Xmas and on reading your post I disassembled to check the rotors as you mention.....to my displeasure I have also noticed that the first rotar with the notches is extremely rough on the inner surface that makes contact with the pipe. The second rotar is not perfect but nowhere near as bad as the first with the notches ...I don't have a Dremmel so I need to think how best to remove the rough surface.......I purchased this item as it had good reviews.....makes you think.....

Thanks
Phil

 

[foxfish]

Hi Phil, welcome to the forum.
You could try using a Stanley knife blade to scrape the edges down (not cut) & then use a fine sand paper if necessary.

 

[Phil Govier]

Hi foxfish - thanks for the welcome. Yes my first thought was a blade but I don't know if a Stanley blade would be too big - I have fine wet/dry "sandpaper" that I could wrap around a dowel or similar and use it like a drum sander.

Thanks again

Phil