Flushed out.

We have had the pumps turned off for the last 4 days in order to kill the biomass in the filters. Today we flushed out to waste the dead biomass and it's contained nutrients. This should reduce the phosphate level in the pool along with other nutrients accumulated by the algae in the filter. The water has remained clear while the pump was turned off. In fact the water remained clear during winter last year as well when the pump was not on - that was before we had the natural filter. But as soon as the weather warmed up the pool went very green. Ralf says we can leave the pump turned off now for the winter! If there is any problem we can always turn it on again. This of course reduces the cost of running this pool even further! We have baby fish - I have counted at least 11 and they are three different sizes- so three successful batches. They are so small -like mosquito wrigglers- that there may well be more that I haven't seen. So come summer we should have quite a display of fish in there. I can't wait for snorkeling weather! There are aphids on the water lilies and lotus. I have been washing them off by submerging the leaves and giving them a bit of a rub, but they then float on the water tension and I suspect spread around the pool. I haven't seen the fish eating them yet but hopefully they will discover the aphids soon. There is a Surphid fly hanging around the leaves and I hope it is predating on the aphids. There have also been a wasp and a spider on the leaves so maybe we will breed up some predators. If anyone has any other control they can tell me about please do so. Of course insecticides are out of the question because of the frogs and fish. There are new froglets emerging now too. That makes three different species we have seen emerging from the water. And judging by the feathers floating on the water we have had guests there before we are up in the mornings. How many chlorinated swimming pools give this much interest and pleasure in winter time?!

Such clear water!

The water is SO clear it almost looks as though the plants are floating in air.

I have taken a few pics to illustrate this since we are about to do the first flushing of the filters.

 Can you see the water in this pic? Unless you realised that the water lily leaves are floating I don't think you would realise this is a water garden because of the clarity of the water.

 This pot looks as though it is floating in air! The whole thing is underwater and the new water lilly leaves are about 18 inches (sorry to those who prefer metric) underwater.

And the water lilly below is in the deep end of the pool. you can see the pebbles at about a meter depth and the bottom of the pool with old leaves on it is about 2 meters depth.

We are still struggling with duck weed which I am determined to eradicate. You can see the tiny green leaves caught on a floating leaf. At least I can see them now I have removed most of the floating plants.

The life in the pool continues in spite of the cool weather. The water lilies and lotus and the water chestnuts are dying back for winter and the plants are not growing so quickly. Surprisingly there are fresh frog egg masses and new tadpoles. There are also water dragon nymph cases on the plants - a different species which is much smaller than the ones we have seen before. Maybe it is the thinner, lighter, blue species we have seen flying about.

And thankfully the toads have stopped challenging our barrier.

There is barely any biofilm visible on the pool walls and on the rocks. However you can feel the slipperyness on the surfaces, so we know it is there.

The flushing of the filters involves turning the pumps off for a few days and then flushing them to waste. This kills the biofilm in the filters so the organisms let go and can be flushed out of the pool. The purpose is to clean the filters and also reduce the phosphates and other nutrients contained in the organisms. This reduces the nutrient load in the pool over all. The biofilm will start up again as soon as the pumps resume pushing the water through the filters. The biofilm elsewhere in the pool will repopulate the filters very quickly. I'll let you know how it goes. Ralf tells me that the water should remain clear.

Duck weed

We are back from our trip. The pool is as clear as ever. The lotus is dying back for winter, but the waterlillies are flourishing. One has a flower bud at the surface so we'll see what colour it is tomorrow. But we have duck weed! That is that tiny three leaved plant (is it a fern?) that covers the surface of some ponds like a lawn. It is quite attractive in a pond but I think it would be disastrous in a swimming pond. I think it would stick to your skin and clothes and be quite unpleasant. We must have introduced it with plants from another pond. So my daughter and I spent some time removing the floating plants and picking the duckweed out from among the remaining plants where ever we could find it. I don't like our chances of eradicating it- it is so tiny and even a single leaf can grow and multiply.