Which Hydor Koralia pump for 55 g.

Well Planted Plants?

I really don't see a bad choice, I really like the Koralias, they move water with far less laminar flow more volume than speed (cut me some slack on the terminology).

You seem to have adequate water turnover, assuming the flow is essentially from one end to the other (an uphill side if you will).

Given your flow I would tend to opt for the smaller, though I bought a bunch a while back, on sale and ended up with the larger ones just based on the small price difference.

Unless you have fish that have some known (as in well documented) need for slow water, the fish are not likely to be affected and likely even appreciate the extra flow. As long your plants are, well, well planted, the only problem with a high flow powerhead is turbulence that can disrupt proper circulation.

Biollante

 

I'm running an XP3 alongside a Koralia 1 in my 70 gal. It's a nice little circulator and you can change the flow characteristics by using the included "fish guard". Without, it creates a very gentle and broad flow. With, it's more comparable to a typical powerhead, though still more broad.

My main issue with them was the size. Having run this guy for a while now, I would go back and do two or three nanos instead. Costs more overall, but I would get better directional control and they're less visible.

 

The Right Choice

Any choice you make will be the right choice!

Biollante

 

Either a 2 or two 1's. Nano's would be MUCH too little in that tank.

 

I too am purchasing Hydor Koralia powerheads. Foster & Smith (online has 40 percent off) has a 60 day return period. At the time of purchase we found them cheaper at Marine Depot, but we wanted to be able to return them, if they weren't strong enough. F&S, has an EXCELLENT customer service, and return policy.

Also, we too, weren't sure which size to get. So we asked around, finally calling F&S. They gave us the Hydor US customer service phone number. We got different opinions from everyone. So we ordered and got the #1s (at 20 percent off). After a week, we didn't think they were circulating past the plants. Then we were notified that F&S, has a new SUMMER SALE, with the p/heads at 40 percent off. So we sent back the #1s and reordered the #2s and still got money back. We are now awaiting arrival of the bigger powerheads(which when installed are behind objects and not visible.)

Actually this concurs with what the Hydor rep said, and others...........get the next size stronger than you need...........Also we can get a dimmer switch at Home Depot, (for lamps)..........and dial down the circulation.
Hope this helps some.

 

I read somewhere on another forum that the standard Koralias will not work in that way. They have a different series that will though and are made for using a variable controller. Have you actually done that with the standard ones?

In my 72 gal I first got a 1 and it was ok, but not really enough. I then jumped to a 3 because I got one used cheap and it turned my 72 gal into a blender and the plants were coming up and the fish blown about and looked none to happy. I gave the 3 to a friend who uses it in his reef tank now. I now have a 2 and it's a good middle ground for my size tank, I think.