CLEANING OUT PONDS : IS IT NECESSARY? AND WHEN IS IT NECESSARY?

It is around about the end of July that it begins to become apparent that although the pond is perfectly healthy, everything in it has simply become overgrown. So perhaps it isAn investigative dredging with a net reveals more rubbish than was envisaged. Time for a cleanout. not just a haircut required at the end of the season, but a thorough sort out is in order too.

Early October is the best time to do it before the frogs decide to call it the end of the season. Also it is an opportune time to check out that persistent drop in water level which you are sure is attributable a small hole somewhere. However if there is an obvious desperate need earlier in the year then ‘needs must prevail’.
If there are telltale bubbles of gas that emerge from the stygian depths of a gloomy pool with a mere casual nudge with a stick or net into the bottom mud, this spells emergency! And something must be done at once to avert disaster.
Of course it’s not your pool, it’s just a nightmare. You would have done something about it long before the mud at the bottom was even 3 or 4 inches deep. But when you see it elsewhere and you net up layers of detritus and leaves, rank with a foetid pong, you can confidently assert that it is time to clean the pool out NOW.
Every pool and pond in the whole world is filling up with muck from animals and rubbish from plant life all the time. In fact the whole world is, and if it wasn't for busy little helpmates to break up the rubbish into its constituent elements, the environment, be it pool or countryside, would very quickly disappear under a heap of leaves and excrement. Ultimately it is bacteria on which we all depend and in the pond it is the heroes Nitrosomonas and Nitrobacter that with a little help from friendly fungi, break up all the organic matter that falls to the bottom. Organic matter goes through a process of oxidation often refered to as the 'Nitrogen cycle' in a pond, when the bacteria break up ammonia compounds into ntrites that in turn get changed to nitrates. These are then absorbed by resident plants as fertilizer. Bacteria are pretty much ubiquitous, but these particular friendly and useful ones need plenty of oxygen all the time to do what they do. So if there is no oxygenating weed (I mean a lot) or there are no fountains, streams or waterfalls or if there is too much to process and they are stuck under 3 inches of unprocessed sludge, they die and are replaced by bacteria that work to the detriment of the habitat, allowing ammonia and related gases to build up that will poison the inhabitants, particularly the fish and especially koi.
The result is the other warning sign; the fish gasping for air at the surface on close airless summer evenings. Get a water test kit and test for ammonia and possibly oxygen. Any reading at all on the ammonia test is an indication of a potential problem and the oxygen level will confirm that.

PANIC STATIONS! EMERGENCY POND TREATMENT

Emergency remedial action is to pump in oxygen by turning on a fountain or stream. If there is nothing like this incorporated in the pool, spray water from a hose at a height that allows the jet of water to push air under the surface. Tap water contains quite a bit of oxygen and although it is not the best thing for fish under stress, it is the least of evils and dropping it in or gushing it forcefully into the pool dissipates a large portion of the chlorine it contains.
If a complete pool clean in the near future is out of the question, carry out the emergency remedy of a partial water change of one third, refilling with water from a hose as above and treating with pool conditioner is a remedial option. For large pools, various retail products such as ‘Aquaplankton’ have had some success in breaking up some of the pool detritus. Otherwise get to it as soon as possible. If you can do this in later September /early October, the water is still warm, and the wildlife and plant life has still a bit of growing time to recover, the water can ‘age’, nothing is hibernating and everything is out that wants to be out.

AND HERE IS WHAT YOU’LL NEED TO CLEAN OUT YOUR POND…..

General:

• A pump capable of pumping thick, muddy water and a large bore hose suitable for the pump and siphoning. This large pond at Blagdon Water Gardens, Somerset, UK, has a tranquillity that belies the problem beneath surface of the water.
An ordinary pond pump may need a bit of help to pump out the pond.: It may very often be necessary to supplement any pre-filter on the pump with the sieving effect of a large lily basket or such like, otherwise your are constantly clearing detritus from around the pump.
• Also plan where it is going to go. A compost heap will only take a certain amount of very liquid material whilst small drains can easily be blocked by the thicker stuff. If you pump it straight onto a flowerbed or a shrub border, it just lies like a thick chocolate icing asphyxiating terrestrial plant life as effectively as it was suffocating the pool. Aim for a manhole drain cover and lift it, but don’t leave it uncovered. People have a nasty habit of falling into holes that were previously safely covered over.

Three days hard work reveals its potential problems, only partially cleaned out and look at the tons of muck.

The tubs are full of lily cuttings and a few fish.: You will need buckets for muck and containers for wildlife, fish and plants. I use old fibreglass pools with nets over them, but water butts would do just as well.

Old but sharp knives or old pruning saws are essential for dealing with knotted and knitted together marginals.

A plastic dustpan and brush is essential at the later stages; a very coarse brush for cleaning off the pool-sides is useful.: Also a shovel; a good net, and some long waterproof gloves are in my mind essential having caught some nasty bacterial germs doing this.

• Water supply and hose for washing down, ‘watering down’ (see below) and refilling.
If dividing the plants and replanting is on the itinerary:
• A polythene ground sheet is useful surface for storing plants and splitting them on.
• Two garden forks or a sharp spade, an old pruning saw and a garden knife. Scissors, secateurs and trowel may be useful.
• All the necessary ingredients for replanting: fresh soil (good garden loam will do), probably new baskets, hessian liners for the baskets and topping gravel.
If you have fish in your pool and the cleanout may take a long time:
• They will need to be kept in the cool with some aeration from an air pump.
• Net for catching fish.
• Tap water conditioner.

METHOD

Frogs can be stored in a deep sided bucket, but they will probably manage to get out. Allow yourself plenty of time. It always takes longer than you expect and it is hard work, so get some help too. Characters like this dragonfly larva will make their own way home.: unless of course you need to keep them out for a time, in which case pop them in a bucket of pond water.
Save as much of the clean water from the surface of the pond as possible that is if it isn’t completely stagnant. Use this to store the fish in. It will also be useful for helping ‘age’ the tap water you use to refill the pool. It will act like a ‘yoghurt starter’ by introducing a thriving culture of the right bacteria into the pool.
Pump out the rest of the muddy water to a preordained place. You might want to water down some of the thicker mud with fresh water from a hose so that it can be sucked up through the pump.
Large heavy amounts of tangled roots and thick mud can be left on the side to drain and to allow the insects, animals and other strange organisms to make their way back into the pool at any time at their convenience. The population of frogs can seem enormous as you rescue one after another, until you realise quite often that it is the same one that keeps escaping from the quarantine you place it in.

Whilst the pond is emptying, you can remove the marginal plants and divide them if necessary. You may find it necessary to divide them in situ just so that you can get them out! When you are struggling with the hippo like proportions of some of the root masses, the old pruning saw comes into its own. However take great care if the pool has a flexible liner to not slip or accidentally cut too far.

The old pruning saw being used to cut up this mass of sweet galingale.On this occasion the giant sausage of root ball had to be wrestled into the bottom of the pool.: Here I was able to cut up from underneath and between the planting baskets.
If there is no time for a replant, carve the plant material away from the original planting baskets. If you do this carefully this is often the best material for propagating new plants especially when it comes to the precious delights of irises and lilies. The alternative of dividing up the contents of the planting basket often means total destruction of the basket.

HOW TO CATCH FISH WHEN CLEANING OUT PONDS

Catch the fish when the pool is almost empty. Although it seems stressful for them to be slithering around in the in the mud, it better than being chased around the pool by a lunatic with a net for half a day and still end up slithering around in the mud. Conscientious fish keepers will take this opportunity to check the health of their fish and treat any ailments accordingly. A tonic of a salt bath would help protect and repair them against the rigours of the upheaval. Cover and aerate the holding tank or containers. Don’t feed the fish.
Continue to drain the pool and use the dustpan and brush with the buckets to scoop up the last few gallons of sludge keeping a beady eye open for small fish. Many wonders reveal themselves at this point; lost toys, money, tench that you may have put in 3 or 4 years ago and never saw again, also other fish of all sizes that you never knew you had. AND not forgetting the strange unearthly beings from the planet Zog.
Despite this being a small pond there was still a large amount of plant material to sort through and divide up.: This will be useful for the replanting of the pond.
Rinse down and brush off blanket weed growth. Dont use detergents but you can paint strands of blanket weed with an algicide if you want.
Check the liner. If you are looking for a leak, check the seams. Also as the liner begins to dry out, holes will become more apparent with water pushing back in through them from behind the liner.

FILL UP

Start the refill as soon as possible, adding the required amount of de-chlorinator to the water. This may take 2 or 3 hours to do its job, so delay the fish transfer.All baskets in place and finishing the ‘fill’. Treat with pool ‘conditioner’. Get on with replacing the plants as the water becomes deep enough to take them, which means lilies and oxygenators first. The marginals go in as the water level reaches the shelf.

For the fish, if there is a big temperature difference in the water in the holding tanks compared to the pool, transfer them in large plastic bags and float them on the surface with the sides rolled down to make a float until the temperature evens out. If you add little bit of the fresh water to the bag over a period of 15 to 30 minutes, this will speed up their acclimatisation to their new water. All this ritual and kafuffle is only necessary if you have particular concern for your fish. I’m afraid to say, I generally just bung ‘em straight in and let them take their chances – it’s a tough world out there.
Once the fish have been removed from the old pool water, pour it back into the pool.
Only feed the fish very sparingly at first and don’t think of adding any new fish at least until late spring next year.

The Blagdon Water Gardens Pond after a complete restoration.: It needed a complete rebuild since the liner had been peppered with holes by hungry herons. Because the pool liner went partly up the waterfalls, it meant the waterfalls had to be partially rebuilt as well.

ATTACKING THE PLANTS AND REPLANTING- (see also forthcoming article 'Replanting Water Plants'.)

Sometimes ‘the big clear-out’ is not necessary but a pre-emptive strike on the water plants is required necessary for the coming season in order to keep the surface clear enough to still call it a pond. It may not be enough just to trim the excess growth emerging from the sides of the basket. The plants may be deserting the baskets completely in the search for more resources in the great beyond. You may also have become aware of an unwise decision in the choice of a particular plant and feel that before it causes a problem you may want to ‘nip it in the bud’, although the more apt analogy in this case may be ‘to take the bull by the horns’!
Get to grips with the clump. Ensure it will come away from its position so that it can be hoisted onto dry land for further attention. Here would be one advantage in having a concrete pond; you can be a little more blasé about hacking lumps off without puncturing the liner. If it is too heavy to lift out it, it is probably best to get in there to pull the lump away from the side and attack the floating corpse.
Sometimes a clump will lift out partially and parts can be removed as it emerges. An old rough steel carving knife or an old tree-pruning saw are favorite. You will find groups of plants sitting in small planting baskets will no longer be separate and came out as one great lump, the plants having grown into each of its neighbour’s basket. The baskets may have to be abandoned.
One important note is that after all this activity of cutting back plants, removing and adding plant material and soil, check the filter and the pump regularly for the next few days. This plant ‘sort-out’ and replant will result in a lot of extra material having to be processed by the filter. The disturbance to the fish will also create more stress, which will also indirectly put pressure on the filter too, so be prepared for a little extra filter and pump maintenance.