Filtration

A visit to “World of Water” for some fish food, prompted me to post this.
I noticed that a filter about a third of the size of mine was over £1,000.
I can remember some discussions we had in a koi society meeting twenty years ago when “new” filters were being commercially produced. A common thought was; “They’ll be telling us those the size of a matchbox will be adequate soon.”
Now I’m not knocking new technology, but in principle what makes a filter work is the efficiency of adequate filter medium to get the biological process to work and the “dwell time” the amount of time the water stays in the filter to give the bacteria a chance to do its job.
You can have the best filter in the world, but it won’t necessarily get rid of green water. This is produced by the action of the sun on the surface water of your pond. The best way to control this is with a UV sterilizer.
For those who are interested, here’s some more photos of my “fish room” and how things work.

“For those who don’t want to know the score….”

This is the header tank, where the water enters pumped from the sump by the side of the pool. The pump is situated near the top of the sump, so it doesn’t take any of the sediment that’s collected in the bottom of the sump between purges. It was painted black but after 24 years…




I can balance the rate of flow to the two sprinkler bars in each top tank, by raising or lowering the short pieces of polypipe in the four outlet sockets. The water comes in from the left. That orange hose connector which can be rotated allows me to trickle change water from the pond through another filter into the 300 gall indoor tank. That tank has a central heating pump
It means I can maintain the same quality of water in that tank as that in the pool, so if I have to bring a fish in, it won’t be in strange water. The green staing on the plastic washers and sealant is malachite, from when I recently dosed the pool. The water is from the sump so it's "bottom water" but is pretty clean although there will be some sediment in it.



All the following is duplicated in the other two tanks. This is the open core foam, which collects any solids and removes the fine particles, the more it gets clogged the better it works. I’ve not run a wet and dry vac over this in three years, so the sump is pretty effective. It’s a bit messy in there as I usually have the top on. But there’s no unpleasant smell.



This is the filter medium under the foam, the foam sits on this “recycled” bread tray balanced on top of the Flowcore. At the bottom of this tank are two “reverse sprinkler bars” connected to outlets at the level of the top of the Flowcore. The actual connection to the outlet from the tanks is by a three way pipe connector with the third orafice facing upwards, to prevent syphoning. The two closed end collecting tubes with holes drilled similarly to the sprinkler bars, ensures an even collection of water and prevent “water tracking” which can be a major problem with some filter designs.



The two pipes coming out of both tanks go down and under the top tank and into the second tank and the water distributed by further sprinkler bars. These too have “reverse sprinkler bars” in the bottom to collect the water which exits near the tops of the tanks. The tank is full of Flowcore and the tops sealed.



Here the two sets of pipes from each bank of tanks return to the pool down near the floor. There’s an additional connection from the UV filter. The pipe on the left is the waste from the sink, to which the overflows from the top tanks are connected. The grey 1" pipe right at the back is the supply from the pool pump. The insulated pipe is the room's cold water supply, with hose connected which attached to the nearest top filter tank so I can trickle change the water as necessary.



Here’s the UV sterilizer I made, I ordered a quartz tube from a specialist company, much cheaper than a store-bought one at the time. I used a re-cycled fluorescent fitting and more “plumbing stuff” It’s fed from a bypass from the header tank and is very effective.
It has a drain hole at one end as a surprising amount of fine silt collects in it which over time would reduce its efficiency. After a lot of experimentation with bungs that didn’t work, I use the hardened plug that gets left in the applicator nozzle of a tube of bath sealant, if you forget to replace the end cap. It’s worked a treat for years.



The tanks are on brick piles and those white rods supporting the top tanks are four pieces of cut-down scaffolding pole.
As I’ve three drain valves, one for the main filters, one for the 60 gall tank filter and one for the 300 gall hospital tank, I can take up any part of the built up floor. It’s decking squares. There's about a six inch void before the concrete floor of the garage. There's a lot of polystyrene insulation under there.



This is the indoor “hospital tank” and filter. It’s “nicely finished” but there’s bits of
polystyrene cladding all over it for insulation in the winter.



Here’s my hot water boiler and sink. (vanity unit from the bathroom “re-cycled” years ago when that “brown” made a change from white.



There's five double 13 amp sockets in this room to feed, the fluorescent over the tank, the UV, three pumps, two tank heaters, two air lines. I guess I've about a total of 20 actual sockets between the garage, fish room, shed and tea house. We havve a fairly new trip fuse box in the house installed with a re-wire 9 years ago. There's a dedicated supply to the garage from a trip switch in that box, through a rather ancient "pyro" connection under the concrete drive and patio raft, to an old fashioned fuse box that takes fuse wire in the garage. But everything connected to that goes through this, an "industrial" sized residual current circuit breaker, which I test now and again.



The only "heavy" load in all that is the 2k water heater, used occasionally and I'm "never in more than one place at a time," so I've no concerns and feel it's all pretty safe, but water and leccy are a dangerous combination and every precaution should be taken.