Originally Posted by Blue Ridge Reef
In my experience, you can almost always replace a filter on a mature healthy tank and not miss a beat. Especially true for planted ecosystems where the filter isn't the end-all be-all for nitrification. The issue I see as being more likely in your scenario is putting the AC50 on the new tank. While a seeded filter will speed up cycling, it isn't always instant and you'll sometimes have NH4 spikes even weeks down the road. My concern for this happening is even higher because you're presumably moving it from a tank with inert substrate to a buffering soil. ADA tends to drop your KH to 0 and pH well below 7. I'm not sure if it's a matter of hardness or pH but there seems to either be some bacterial die-off from the parameter changes or they at least take longer to establish back to numbers that can convert your NH4 all the way to NO3. Plus ADA releases NH4 for the first 4-6 weeks typically. I think what you have in mind will work, but don't be in too big a rush to add livestock to the new 33 gallon tank.
Blue Ridge, Thank you so much for your detailed response. You are right in that my AC 50 is moving from a inert substrate to a buffering one. What I failed to mention is that although the 33G is 48x12, only 28x12 of it will be aqua soil the rest is pool filter sand. Furthermore out of all the aqua soil that im using, only 50% of it will be new. The other 50% is coming from another tank I have. Knowing this, I have a few more questions
1) will the cycle be instant or still take a few weeks ?
2)would you suggest heavily planting from the start or letting it cycle first ?
3) Would you mix the new and old aqua soil together or layer the old on bottom and new on top? or vice versa ? or it doesnt matter? lol