Deer in the headlights! (inherited pond)

[silverctr]

I recently became the main maintenance guy for the Japanese garden at a local community park which includes a sizable, outdoor koi pond shaped like a giant horseshoe. Whoever designed this pond was off to a good start with a six foot, cascading waterfall and a couple of mechanical filters at the waterfall pump intake. Where it goes outside of my realm of knowledge is that the water is constantly being changed. It is always draining into a manhole, while my water features pump fresh water back into it. There's no valve to stop the draining either, but there is a basket to catch leaves, etc. before it leaves the pond. The odd part is that it doesn't seem to affect the assorted koi or the water quality( which isn't an issue anymore since I stopped feeding them everyday). There's no biofilter present, no vegetation (like hyacinths or lily pads), but a nice brown sludge that covers the bottom. I'm assuming the brown sludge is a nice buildup of decomposed vegetation (tree leaves, etc.), and fish poo. I have no problem removing tree litter from the surface thanks to a small skimmer and a pair of waders.

So here's my questions:
1. Should I block the drain to make this a closed system? And then install some sort of biofilter at the intake of the waterfall pump?
2. Should I clean the bottom? If so, what's the most efficient way?
3. Should I bother adding vegetation in the water even though just a small portion of the pond sees about 6 hours of daylight?
4. My knowledge to this point doesn't go beyond small 10-20 gallon indoor aquariums.

What I have to work with:
-handheld pool skimmer
-brush and/or push broom
-2-6 hours of labor time solely dedicated to the pond, per week

I would greatly appreciate any and all comments, suggestions, etc. so I can give the park patrons their money's worth since I've been told it's the "jewel of the county". :banana:

 

[addy1]

Welcome to our group!


Koi will eat anything you put in the pond, most of the time.

Having the water constantly change is one thing a lot of ponders try to have happen, fresh water, happy fish. I would not block it. Assume it is not chlorinated city water, ow fish would be dead.

If you want to clean the bottom a pool net works great, I use a leaf net.



With the man hole you could just brush any bottom muck towards the man hole let it flow out with the water.

 

[Mmathis]

Are you sure the water isn't being recycled? It could be that the water going into the "manhole" IS being returned, but is being diverted underground, maybe like they do with the pond-less systems. If you could, take a few pictures for us.

 

[silverctr]

addy1, The leaf net is a fantastic idea! Plus I'm happy to hear that I'm better off than I thought I was. Brushing the bottom will definitely be a chore and probably take me a few days(maybe weeks?) to do. I had brushed the sides last week to see what would happen. A lot of the gunk had just settled back down, but there were a few clean spots that looked promising.

Mmathis, I definitely know the water isn't being returned. I turned off my water feature(which pumps in fresh water) one day before I left work and when I returned the following morning the water level had decreased about 20-25%.

Here's a couple of pics I took back in early May:

panoramic view

 

[addy1]

Neat looking pond! bet the fish are happy campers.

 

[nancyp]

Addy1 - where would I buy that leaf net for the bottom? I can't seem to locate it.. maybe I am looking in the wrong places? Is it for a pool maybe?

 

[sissy]

nice pond you have to maintain there Alf :cheerful: set up something to catch all the fine stuff like a basket with filter material and a pump to pump it into the basket would be nice .I used a shop vac and put a hose on each end and a basket of media on the out let side .Only thing was I could see my fish and with that big a pond you don't know how many babies you have .It really does not look bad just maybe a little muddy from rains ,If you can see the fish from there it is not bad

 

[silverctr]

Thank you for the kind words. The panoramic pic is a little misleading when in actuality, it's only one end of the pond. I'll have some more pics up as soon as I upload them from my phone.

Sissy, the shop vac is a keen idea, but unfortunately it's too loud and not big enough for me to use. I can't even use my gas powered equipment during the garden's operating hours.

I also forgot to mention at times there's some kind of slimy layer on the surface of the water. It might cover about 100 sq.ft. and varies in location from day to day. Do koi have a slime coat that they shed?

 

[silverctr]

Neat looking pond! bet the fish are happy campers.

It seems like they are. Since I started brushing the sides they've become very active. There's even a couple of young ones that jump out of the water for bugs! :claphands:

 

[Mmathis]

Addy1 - where would I buy that leaf net for the bottom? I can't seem to locate it.. maybe I am looking in the wrong places? Is it for a pool maybe?

Yes, it's a pool skimmer net. I GOOGLED them a couple of weeks ago, and want to say I recall AMAZON had a slew of similar nets. I like that style because of the extra netting -- looks like it will pick up more per scoop that the standard, flat skimmer net.

 

[addy1]

Addy1 - where would I buy that leaf net for the bottom? I can't seem to locate it.. maybe I am looking in the wrong places? Is it for a pool maybe?

It is a swimming pool leaf net, The front lip has a nice flat edge, helps it pick up very nicely. Nice large net, fine weave picks up a lot of stuff.

http://search.yahoo.com/search?p=swimming+pool+leaf+net&ei=UTF-8&fr=moz35

 

[silverctr]

I just added more pics in the Garden Photography section.

 

[CometKeith]

Hi Silverctr, Good luck with this project. Logically thinking the fish are doing well in the current condition the pond is in and probably little needs to be changed. Many times people want to improve the aesthetics of an existing pond with disastrous affects because they do understand how ammonia, nitrite, and nitrate are being synthesized by biological agents in the pond. Even though it is part of your job description to maintain this pond I would be very cautious about doing anything that would change the chemistry of the pond. The slimy coating on the sides you are trying to clean up are actually composed of beneficial bacteria that will help neutralize harmful elements in the pond water. It also provides a natural food source for the fish. I agree with everything that Addy is suggesting in terms of using nets to pick up debris but do little else until you have a better understanding of what makes a healthy pond for fish.