That's an interesting post there... Thought I’d get this in before the fireworks start…
Built my first koi pond in 1968...kept ponds but quit raising koi in the mid 70's because got tired of fighting the green water...
Re-activated koi pond in 2003 when I learned about bead filters, the Aquadyne in particular...I've found the conversations re: filtration very interesting, but I find one common thread...When we find a deficiency with a particular design we move onto the next "BEST" solution without resolving the actual problem...
In the past few years I've seen the hobby go from , Bubble Beads, to Aquadynes, to Aquabeads, to Ultima Bio, and finally to Nexus, the final solution, but wait, the final solution was not so final after all because they've now refined it with the EASY...I actually like this approach, you invent something, find that it doesn't quite meet your standards so you modify it to improve it's performance...Way to Go...
Back to Bead Filters: The set up of a bottom drain, to settlement tank, to pump to pond was OK as a start... Our system is same but without settlement tank...Then I read that back flushing weekly could harm the Bio filter...and THERE WAS NO GIN CLEAR WATER (white man speaks with forked tongue) Rather than chuck the system in favor of the next "BEST" solution... I added a UV...Viola' Gin Clear Water...To improve the Bio filter I added a TT, thanks to advice from
that guy in Jersey...then I went one step further, thanks to Dick Benbow, Maurice Cox, John Sprinkle, Steve Castel and others I added a Bakki Shower...Also do a 10% constant trickle water change 24/7...
Results: Gin Clear Water, Zero reading for all stuff bad, pH 7.5, dH 3, ORP 400+ (after Bakki install)... 8 koi (until I built second pond) living in 900 gallons of water 2.5' deep growing from 8.5" to over 22+" all in a little over a year....Great shape, great color, still growing...
New 1700 gal pond uses same design except improved with 4" bottom drain, no dome, no aeration, Aquabead Filter (improvement in through put volume), to Bakki shower...Same great readings as 1st pond, koi growing like weeds...expect tosai of 7" and nisai in 12-17" range to top 22" by this summer...
Aloha! Mike