I'm new here but I would be wary of any name brand sold at big chains.
Check the model numbers carefully. If you cannot find the same model
numbers in the manufacturer's catalog they are most likely made in such
a manner as to make the $169 price possible.
Mark B.

Janet wrote:

*waves from Niagara Falls*
I agree with the others, no chemicals. If the murkiness is from muddy rocks
and it's good Ontario clay you may need to drain, clean it out and refill.
There's something about Niagara Escarpment clay that just doesn't want to
settle out of the water. DId you buy your kit at Home Depot by chance??
Hubby was telling me yesterday that they are now carrying Beckett pumps
which are very reasonably priced (4500gph waterfall pump priced at $169!!)
Now's the time to be thowing in the plants. If local nursaries don't have
their water plants out yet grab some anarcharis from local pet/aquarium
store. Mine is growing like crazy right now. It overwinters in the pond.
Iris is good in the pond as are many other plants. You'd never be able to
overwinter koi in 550 gallons, think comets and other goldies. Be prepared,
you will have algae, it's not all bad. )

Janet in sunny, warm Niagara Falls where the fish are spawning like
rabbits! P