Fertiliser Production

This is the cover of my filter pump sump. The only clue to a filtration system for our koi pool. It's a big green 40 gall water butt, set in concrete.



The sump is connected to the bottom drain (under that big dome in the middle of the pool) by a 4" pipe. Those "white" bits near the bottom drain dome cover are fish pellets sitting on the bottom of the pool 5ft down. That's how "clean" and clear the pool stays.



The filter pump pushes the water up a pipe buried in the pool collar to the filter in a dedicated room in the back of the garage. It's an old system I mean, 32 years old, formed from four 40 gallon water tanks a lot of polypipe 12 sq ft of 2" open-cell foam and enough Flowcore to fill a Renault 5 GT except for the driver's seat, cut-up 4" bits of corrugated plastic pipe. (I had to collect it from Stoke, I just hoped I didn't get stopped by tthe police 'cos I couldn't see out of the back or passenger side windows).




Here's the science bit.



The water passes through the foam, through the Flowcore and out through the bottom tanks by four 1.5" pipes back into the pool.
The fine particles stay on the foam, the more blocked the foam becomes the more efficient becomes the filter. The only maintenance is a scrape of the foam with a wet n' dry vac every couple of years and in November I drop all 130 plus gallons out of the tanks through a valve in the bottom of the filter, then let it fill up with pond water again.

This old system has been superseded by far more expensive systems that need a lot of maintenance. My water parameters are boringly consistent.

Once a week I turn off the filter pump and put a bung on the end of a log rod in the socket at the bottom of the sump. Then pump the contents to a house drain under the kitchen window via a 1.5" pipe buried in the pool collar and under the patio. When it's drained down, removing the bung forces 40 gallons of water including all the gunge sitting in the 4" pipe under the pool up into the sump. The bung goes in again and the contents again pumped to waste. But the drain pump can't shift the last ten or so gallons. So I need my trusty Nilfisk wet n' dry vac to shift it.

After vaccing, all traces of gunge have gone. I just pull out the bung and sump refills with "clean" water.
The filter pump is on the left, the drain pump is sitting on the bottom and there's a bypass pipe from the filter pump with a valve in it which feeds the waterfall.






But I'm left with this disgusting stuff.



I dilute this 50/50 with pool water and feed it to all our rhodos, azaleas and acers.

They love it!

 

That's one hell of a system, very impressive. I struggle with ornamental solar lamps, never mind a whole water treatment plant for a pond! Out of interest, have you ever tested the pH of the slidge you use as feed - not a loaded question, am just curious!

 

Thanks for the interest, but to be honest I've never tested it. I rely on the fact that koi keepers, generally speaking, have always considered fish poo slightly acidic.

It's known that fish pass twice their own weight in urine...daily!

So I guess that's "the deal breaker."


Given that our soil is naturally sandy in that at one time it was alluvial as we're in the Mersey basin, I think it's the "wrong" sort for acid loving plants.

I'd add that as well as a UV and a dechlorinator for the 24/7 pool water trickle change, the disturbance on the surface of the water in the bottom left corner of the second photo, is from the water returning from the filter plus air coming up from air stones at the bottom of the pool from a 24/7 1000 ltrs. p.h. air pump. The air lines pass through two of the filter return pipes.