Water flow During Winter

[Dennis Woollum]

I currently run water from the bottom drain and skimmer to the settling chamber and filters, then through the bio tanks, then through a bio-falls waterfalls box to the stream/waterfalls at appr. 3000 gph.

I am considering running the system at perhaps 1/3 to 1/2 flow but by-passing the bio-falls, stream and waterfalls and running back to the pond just under water level so there is no splashing at the surface.

Will drawing from the BD disturb the bottom water enough to negatively affect the fish during winter by cooling the water somewhat and causing some current down there?

The water temps last year got down to about 45 at the coldest for a short time. It doesn't get too cold in the California Bay Area. The advantage is keeping flow through the bio tanks is so (hopefully) not all good bio will die, and keeping the skimmer working for leaves etc.

[dick benbow]

I think in your case continuing to feed water thru the bio filters at the same speed as before (summer) to maintain water quality is important. Diverting the rest to bypass the chilling waterfall is a good idea. I would not recommend slowing the flow thru the filter to slower than before. In the mid 40's contrary to popular belief you bio filter is still active. The filter handles less at these temps but the koi also produce less so it stays in balance...... If you don't run the BD
with the koi sitting on the bottom, then urine and other pollutants will build up.
My experience says i would rather give a little on temp than water quality. Before i heated my pond, if the mean temp never dipped below 41 degrees my koi got thru winter just fine. Maybe in the future you could plan to give some thought to a protective cover (stilkl venting for gas exchange ) and maybe a small spa heater that could hold a temp overnight......

[keokoi]

Pretty much same comments to DB's only to remind you that at lower temps O2 levels are at its highest so aeration and or water distrubance is not fully needed and also your probably going to cut back on feeding and or fast so water will be 02 saturated..


Joe

[dick benbow]

thanks Joe, good point about the 02

[Regenmeneer]

Quote: Will drawing from the BD disturb the bottom water enough to negatively affect the fish during winter by cooling the water somewhat and causing some current down there?

If I read this correctly, you are thinking about stratification in your pond. The idea is that becuase water has it's highest density at 4c, water in the lowest parts of a big body of water never becomes colder than 4c. This will be your lowest strata or layer of water, and on top of it can be colder or warmer strata.

Unfortunately, there are two problems. First, stratification will not occur if the depht is less than about 5m (which should about 15 to 16 feet). Second, even the movements your koi will be making are too much to keep the stratification in tact.

About using less flow, remember that less flow through your pipelines from the bd might cause debree to settle in the pipes, which might cause rotting, less o2 and even places for undesired bacteria to thrive. So IMHO, keep the flow.

Regenmeneer

[Rich L]

Hi Dennis,

If the water is moved by two pumps I don't see any reason not to turn one off. The lower metabolism and feeding won't need the higher turnover.

There won't be much for the bio to work on so the colony will die back to balance with the load which is determined by the waste buildup + the turnover.

Stratification is a problem below 40 degrees so I don't see that as an issue for you and I can't see a problem with cutting off air and water falls.

Covering the exposed water will keep the pond a few degrees warmer at no cost other than the expense of the materials. If you do cover, it's a good idea to have a space between the cover and the water. It might be a good idea to add some air in the pond to help exchange air stale air out of the trapped soace.

[Dennis Woollum]

ok, thanks folks. Rich and Joe, haven't talked to you guys for a while.

I'll maintain the system flow level as is with the by-pass return pipe flowing mostly below water level. I have already stopped the BD air diffuser. Good thought about maintaining the flow rate to avoid any build-up in the BD line and remove any urine etc., even though there won't be any feeding.