Questions about upgrading a canister filter on an established aquarium.
After some research recently, I realized that my Cascade 1500 only puts out around 320gph. I have a 55 gallon aquarium with 3 fancy goldfish (body size, not including the tail is about 2-3 inches), and the gph recommendation for goldfish seems to be 10 times the tank size. (This tank has been running for a couple years now. It was originally cycled with pure ammonia. Although I have recently - 6 months ago - moved to another city where the tap water quality seems to vary by quite a bit on a daily basis.)
I did some research and came across the Fluval FX4, which boasts 700gph (probably less in practical use). I was thinking about upgrading from the Cascade to the FX4, by moving whatever established media that can fit, into it.
The FX4 has about 1 gallon of space for filter media, while the Cascade is probably around 4-5 gallons of space for filter media.
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Is meeting the suggested gph more important than the extra 4ish gallons of media space?
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Will I potentially go through a cycle period by losing 3/4 of whatever BB may have been in the previous filter, but now doesn't fit?
I don't want to run 2 canisters at the same time. (The flow would be too much for the fancies and there isn't really space for me to do so.)
Experience and advice would be greatly appreciated.
Posted Apr 23, 2017, 8:08 PM UTC
If the water parameters are fine and the fish are healthy I wouldn't worry about it. You can get away with less volume/hour in a canister because there's a lot more surface area for the bacteria than in a HOB.
If you're worried about the current being too strong for the fancy goldfish, you can reduce it by angling the spraybar upward slightly so that the water output slightly breaks the surface.
My water params are sometimes fine and sometimes not. It's entirely dependent on my tap water.
I do treat the water with Prime, and since I saw a random ammonia/nitrite spike recently, I've been dosing Stability and Stress Guard as well.
I recently had a fish die with no signs of illness or disease prior. I immediately treated the others with some medicated food, but from what I read the medication shouldn't have hurt the BB. Maybe the binders in the food made the water nasty. (The dead fish couldn't have been in the tank longer than 6 hours before I got home and removed it.)
I do a weekly (sometimes twice per week) 30-75% water change, depending on parameters.
I'm kind of excited about needing less media in my filter if I do change it (for money reasons), and I like the idea of the water cycling through it more frequently. I'm just not sure if area or gph are more important. A lot of people keep goldfish with a couple HOBs, so I imagine a gallon of media should probably be fine. Just not sure about the sudden change/loss.
take out most of your biomedia and see if it affects the water quality, then youll know how it will be with the smaller filter