string algae

We have a problem - not insurmountable but annoying. When we flushed the filters ( see last entry) this was the first time we had operated the valves. There were a couple of problems (a rock in one valve preventing it turning, and one valve back to front). This resulted in flushing of nutrients back into the pool instead of to waste. We rectified this as quickly as we could but I think a significant amount of nutrient went back into the pool. So instead of decreasing the total nutrient content on the pool we increased it.

Up to that point the pool was looking great as you can see from these two photos . There is very little algae showing on the walls or other surfaces.

After the flushing we left the pumps off since we didn't expect any problem during winter. Then we went away for a couple of weeks. When we came back we saw the hair algae.

So I immediately turned the pumps on again. I also decided that the bottom of the pool should be vacuumed and the sides brushed down to give the filters a chance. But the algae has continued to grow. Of course there would be very little biomass in the filters after first being turned off for 4 days, flushed and then left off for another 2 weeks. So now we are waiting for the biofilm in the filters to re-establish and then to lower the nutrient levels again. The pumps were turned on again 2 weeks ago.

 You can see from this photo that there is algae on the bottom of the pool and on the step. This algae did not want to be swept away- it is firmly attached to the surfaces. By the way the black spots on the bottom are large tadpoles! Even at this time of year we still have tadpoles. However they don"t seem anxious to crawl out of the pool. I don't think they are developing during winter. They are native frogs and definately NOT toads.

And in the next photo you can see the green rocks. you can also see that the water itself is sparkling clear. I don't really mind the appearance of the algae and I'm confident it will clear up as the filters kick in again. Luckily is winter here and algae is not too vigorous. If this happened in summer it might be a different story!


However it is a reminder that this is a living system, and so it is not static. And therein lies the interest!

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.

The biofilm begins

It is now a week since we started filling the pool. The water which started cloudy from the dusts and soil has cleared nicely. It is very clear. We have continued to plant into various planters and pots. We have a cumber of water lilies, the lotus, bull rushes, reeds, kana kong, iris, allcasia - all in the filter bed area. This is in addition to the plants in the shallow step area. Last night we had frogs calling from the pool, and this morning we have 2 egg masses in the shallow area, one under rocks and the other in a floating plant. There are also a few isolated tadpoles in there - goodness knows how that happened. There are many water boatmen. Today I saw dragon flies laying eggs among the floating plants. Yesterday I saw an adult female water dragon (P leseuri) and three very small baby dragons, all at the same time in the pool and on the surrounding rocks. But the most important development today is the beginning of the biofilm. This film of biological activity which forms on all of the surfaces of the pool is the engine room of water cleansing for a natural system like this. Not only is it forming on the walls of the pool but also inside the submerged filter system. We plan to leave it undisturbed except on the steps where it could become too slippery. Once the system settles down there should be a thin film of life but initially it could be quite significant, especially in view of our high phosphate levels. So we are watching the developement of our biofilm with interest. It is a very welcome sign that nature is taking over. Once the biofilm develops it will also sustain the insect life which we expect in and around the pool. There will be herbivores which feed on the biofilm, and then carnivores which feed on those. The first of these carnivores will ne dragon fly nymphs. These little critters are ferocious hunters of small insects. We will see their skins where they have crawled out on the water plants to hatch out as adult dragonflies and fly away. In the meantime we are enjoying the swimming.