Cleaning the biological filter during the month of Autumn

Is the same as the spring clean but bear in mind that you are moving into a cold season there the filter may be operating largely mechanically. The priority therefore is to just get the bulk of the muck out. If the water gets very cold and ices over it will have to be switched off, in which case it would be best to replace the filter medium when it is time to restart filter. This would be when the water achieves a mean temperature of over 5C (40F). Biological activity would then begin. The pump needs to be replaced at the margin shelf level if it is getting cold so that only the surface water is circulated.

Serving a U/V clarifier

History

Once upon a time it was observed that a source of Ultra Violet light in close proximity to water very quickly destroyed all the bacteria in that water. The UVS, or Ultra Violet Steriliser was born. Consisting of a tube that contained an Ultra Violet lamp through which water was pumped, it was an invention that very quickly became a boon to hospitals, seafood farms and drinking water supplies in the third world. Aquarists were very quick to latch on to the fact that not only would this lamp kill bacteria but it would also put an end to algae. Unfortunately, the very effectively sterilised water, ironically, did not make for healthy fit fish.

However, a little bit of research soon ascertained that a compromise was in fact an ideal. It was found that a certain dosage below a completely sterilising effect causes the algae to flocculate or cling together in lumps that drop to the bottom of the pool, then these lumps could be easily taken up into a filter system, leaving the water clear. Thus was born the UVC or Ultra Violet Clarifier.

This is a piece of technology that is administering a scientifically precise and dangerous amount of Ultra Violet light. Electricity and water are a millimetre apart. In order for it to be efficient and safe, it needs conscientious and regular maintenance. Unfortunately, up until recently these contraptions have moved very little further in design from their garden shed Heath Robinson collection of waste pipe plumbing and kitchen light electrics that definitely needs as much protection from the weather you can provide. Even if the were water tight, ambient dampness plays havoc with connections and clamps and sunlight and temperature changes make for wickedly stubborn hose tail connections and brittle plastic tubing. On top of this there is usually the agonising frustration of trying to maintain such a delicate item whilst contorted into some tortuous position whilst accessing the undercover filtration chamber.

Must dos

• The actual lamp light itself is delicate and very quickly loses its efficiency and must be changed as regularly as the manufacturer recommends usually every six months but at least once a year.

• The lamp very often sits within a quartz sleeve. Quartz was found to allow UV light to pass through it more effectively than glass. It is expensive, very brittle and needs to be kept spotlessly clean. Some manufacturers recommend that it be changed on a regular basis.

Lets get at it

Tools Required:

Screwdriver and the sort of resigned patience that you imagine Jonah might have had.

Method

1. The inlet pipe and outlet pipe are detached with care.. Beware of stabbing yourself as seems inevitable by my method in the picture. I didnt do on this occasion, but have done subsequently.

2. Remove the cover of the U/V box. On this model it exposes the electrics and the starter switch mechanism. The actual bulb for the Ultra-violet light is fitted within the plastic tube within a delicate quartz glass sleeve. Hopefully this is still water tight and at least clean on the inside. The lamp bulb should be changed after every 6months of use - minimum.

The end caps that the U/V lamp bulb fit into need to be eased off very carefully. Here I am having to prize them off delicately with a very fine screw driver. The aluminum pins that fit into the sockets build up oxidation that causes them to stick. This makes for almost inevitable breakages, but since it is usual that the U/V lamp bulb is going to be disposed of anyway, we can live with the bulb breaking. It is the quartz sleeve we have to be careful of.

3. The U/V lamp bulb will generally show signs need of age with telltale signs of mercury deposits at each end of the tube. This shows that its efficiency is waning.

4.  Check the interior of the tube for any dampness or grit, then wander around the garden for a while looking at wondrous kaleidoscopic effects.

5. The gradual build up of lime deposits on the outside of the quartz sleeve make it is imperative to regularly remove the sleeve to clean it. Some manufacturers recommend its regular replacement, but they are expensive. If there is no prospect of obtaining a replacement quartz sleeve if you should happen to break it in the process of a full servicing, take a short cut by rinsing it through the inlet with clean water. Try to find a supplier for a replacement soon because you will need it.

6.  If replacements are readily available and you intend to do the job properly, unscrew the compression end caps and carefully remove the O rings, making a mental note as to how far they were pushed onto the quartz sleeve.

Delicately withdraw the quartz sleeve to see how clean it is. Try not to touch it too much with dirty or greasy fingers.

7. Clean as a whistle and I havent managed to crack it yet! But weve still got to get it back in and tightened up yet. It has been carefully rinsed on the outside and polished dry with a cotton cloth.

The main plastic tube is given a thorough rinse through.

8. The quartz sleeve is reinserted in the plastic tube. With the O rings in place, the compression end pieces are screwed on evenly and tightly.

Insert the U/V lamp bulb into the quartz sleeve. Do not touch the glass of the bulb. The grease on you fingers reacts somehow with the glass to reduce the life expectancy of the bulb to seconds rather than months.

Insert one end cap onto the plastic tube; feel for the pinholes by twisting the lamp bulb by the pins from the other end. When you feel it located, gently push. The other end cap is replaced by aligning the cable from the back off the end cap to the same direction as the cable emerging from the unfitted end cap. If it is just right you will feel the pins locate in their contacts. If you can feel this positively then gently push the two end caps home together. If you are unsure, give a little gentle twist this way and that, feeling for a gentle positive response from the other end.

9. With the lamp bulb back in; replace the lamp unit back in its fitting and screw on the lid.

Reconnect the unit to the filter box with the inlet and outlet hoses. Lubricate the fittings with a smear of waterproof grease.

10. Grease up the jubilee clips and tighten them up.

11. Turn the system on. Only now can you check if the lamp is working i.e. whilst the water is rushing through the U/V. You must never check it by looking at it directly, nor must it be on for any length of time without water effectively cooling it down as it rushes by. You can only look for a gentle blue glow through the compression cap or hosetail fittings. This is difficult in bright sunlight so you may have to wait for nightfall. I produce a blanket and make an enclosing cowl like Victorian photographers had over their cameras. This generally proves sufficient.

Take your time and dont rush away just yet. Watch for any leaks at the joints that you have disturbed. It may be a few minutes before the flow of water reaches its maximum and then drips and leakages become evident.

For the future

As time goes by, the natural dereliction of the materials used in these designs will mean that they will need to be replaced. Fortunately new designs are overcoming the old inherent problems with snap and twist fit maintenance procedures, as in this Hozelock/Cyprio Vorton UVC. Bulbs are easy to change and the configuration of fittings can be altered to suit any layout. For even more ease of maintenance, the whole unit can be unclipped from its base plate to be dismantled and serviced elsewhere in comfort.

Installing the Hozelock/Cyprio Vortoon UVC.

Show the easy method of changing the lamp bulb.