I saw the colombo version in the LFS also very discrete little container. Smaller then 500cc it looks like a 250cc to me, but didn't check . Tho i might also effectively only fill 400cc in a cut pet bottle.. I bought the colombo refill can..
But seeing the pH profile, it is remarkably stable during the intire light cycle.. If refilled every morning and the bottle slowly empties the co2 and refills with water. By the time it reaches the point it reduces the pH the light cycle is over. Next morning when it needs a refill pH is back at 8. From that perspective it kinda works a charme, having an almost 1 unit drop.. Since it is in my case from a rather high over pH8 starting point it aint enough to make the dropchecker react very much it stays in the blue range. But for a small low energy tank i guess it's a decent helping hand.
I'll give it a try with the bottle submersed and see if the water gasses out less into the bottle. Not going to make predictions, was far off with the first one too, this time i look before i leap.. 😉
But a vent is necessary anyway.. I don't see much waste venting it every 2 days to have the optimum out of it. It is a darn waste with using the spray cans, that's a complete rip off, no fun with almost € 1 for 1 gram of Co2.
