Simply Koi and More Koi

Hi all
I am new to this site and also new to keeping koi carp.
I have just moved house and inherited a 3800 gal pond with a waterfall with x17 large koi carp.
The house had not been lived in for some time and so the pond and filters were in a poor state, although the fish had been fed and were all healthy.
There was an old brush and sponge filter system which i had been cleaning for weeks, but not getting the pond very clear.
I had water samples tested which came back good and also replaced the UV cell. This improved the pond, but filters still dirty every week.
I was advised the filter system may be too small and was told to upgrade this.
I managed to get an ex-display nexus 200 cheap, which with some help installed it and this has been in for a few weeks and seems to be slowly getting the pond clean and the filter is very easy to clean.
I have a old Aronaut AV20-2DNS pump which pumps from the filter to the waterfall. I think the pump is too powerful, because when switched on it drains the filter and the only way i could stop this was to tap off the outlet of pump and send it back into the filter. this does seem to be working.....just.
But i think the main problem is the plumbing of the pond, the pond and filter works on a gravity setup, but the outlet from the pond is a 4" pipe which sits in the pond about 12" below water level, so there is very little head pressure to send the water to the filter (which is about 30 feet away).
I do not think the water is being turned over enough through the filter.
Does anyone have any suggestions to improve the setup i have? I think having a bottom drain would be better,but is this possible without draining the pond? or is there another solution?
Kind Regards.

Hi,

Welcome to Koi Quest

Well it sounds like you have all the bits you need for a good set up and are on the right road and all we need to do is just mess about a bit to get the set up functioning correctly. One of the main problems with most ponds is insufficient filtration and poor or incorrect turnover be it either to fast or to slow but once you get these correct and the system working correctly it slowly starts to all take shape.

The gravity set up is good and yes the only way to fit a bottom drain is to drain and cut one in although there are some types of in pond bottom drains which may be worth looking at if you wish. With you set up you will have a far amount of waste sitting on the bottom which will not get into the Nexus which will not be helping with you water so in these cases most have a hoover and hoover the base of the pond to keep it clean.

If your pump is draining the filter then this could as you say be the pump being to powerful or a incorrect water level either one will need to be addressed.If you have any pictures of the set up may be handy so we can see whats what and may even give us some ideas

Is the water level at the top of your Nexus

What's your location ?.......if you're not too far, someone from this BB could pop around to advise in person, but I do agree with what Gazza has said.

Hi, welcome to the forum.

As Gazza has said the inlet to the filter (outlet from the pond) is too high to remove the majority of the waste from the pond so a bottom drain is the way to go. This would require the pond to be totally emptied, but you could get a temporary pool / vat to house your Koi whilst the work is being done. You could buy a second hand one off ebay or one of the many koi forums and could probably sell it for around the same amount you paid for it when you’d finished the work.

The Nexus is by and large a good filter and does the job. I suspect, as you have already said, that the pump you are using is far too powerful and is pumping the nexus dry because of that. The maximum flow rate of the Nexus 200 is 2,200 gallons an hour. I use a Sequence 10,000 Eco. These are generally thought to be reliable and are economical to run. Others use pumps from the Oase Aquamax range and have a good reputation for reliability too.

The problem with returning the water from the pump back into the filter is that you are filtering filtered water, so it would be better to resolve the pump situation sooner rather than later.

The pond vac suggestion is also a good one. One of the reasons the pond is murky could be that the accumulated detritus is just being stirred up by the Koi, either way it is not going to be doing the water quality any favours and it is better out than in.

Pictures would be good to help visualise the current situation. Is the pond raised or all below ground level. Also how is the pond been waterproofed / lined, ie is it fibreglass, butyl pond liner or perhaps G4 / pond paint ? Also the pond shape, is it rectangle, or irregular shape, does it have any in pond returns, a skimmer etc.

Anyway as for suggestions, obviously only going on what you have said already, but I think I would move the outlet higher up the side of the pond and make it into a skimmer line (if you don’t have one already) gravity feeding into an Nexus Easy Pod. This would increase your filter capacity which at the moment with a Nexus 200 and your ponds stated capacity is only just big enough. I would return this by pumping into the pond at mid water with the option of also having it return over the waterfall with the turn of a ball valve. This would mean you wouldn’t have to return the water over the waterfall in winter.

I would then add an aerated bottom drain gravity feeding into the Nexus 200. I would pump return the Nexus 200 into another (ie separate from the Easy Pod return) mid water return direct into the pond, this would hopefully start a good circulation and flow going around the pond and help the poo ect to find its way into the bottom drain. The Koi like a good flow too.

When putting in the bottom drain, run an air line in to the pond for the aerated bottom drain.

I forward to seeing some pictures.