How fine is the sand residue in the pool? Filter sand is in the main quite coarse. I wonder if your fine sand is coming over from Africa?
Big issue with me south of Carcassonne. Pretty well every storm coming up from the south deposits a bit of Africa in the pool - mostly pink sand which i am told is Sahara…?
With two filters, are they in parallel or series?
I’d consider doing this if it means I caould get double the benefit…
I splashed out on several sacks of AFM glass and cautiously say that the filtering is better, but maybe also due to my change in cleaning pattern. Before, with scant regard to water and due to the sand filter letting it all back in, I used to vac out to waste. With the AFM and eco in mind, I vac to filter, followed very quickly with a backwash with pretty good results. I did wonder the other day if a smaller filter in series, agin with some AFM glass would make it even better? Especially as in another thread, you indicate that AFM glass lasts for ever…
The filters are arranged in parallel, each having valves to shut one or other off meaning a better backwash force but air assisted works better and saves water so things have moved on. This also means not maybe having to use 63mm pipe and fittings that could reduce install costs. Early on I used a WaterCo multi spin, a sort of Dyson for pools, it acts as a prefilter, but I noted it reduced the flow to an extent on my pool I got 3 turnovers per day not 4 so sold that on. Yes AFM lasts, no sign of it not doing its job, it does the best at the correct flow which most single speed pumps are too fast, hence reducing the speed saves enough money to fork out for the AFM and other stuff to improve the system. Before the rise in electricity prices I worked out over 10y a saving over €3000 and of course better water quality.
Of course. Parallel - in series would mean backwashing into the next filter. D’uh!
How do you assist backwashing with air - again? I ask again as you spoke on the subject a couple of years back, but the conclusion was that it was not a simple matter for domestic pool filtration as the subject had not been addressed by the manufacturers. `has anything changed?
Ah well I spoke to an Italian company engineer at the Lyon trade show and may have also mentioned it to an English swim pond filter designer and both have done it on their production units so now happy to share it as I couldnt be bothered with trade marking etc. It takes a bit of work customising the multi port if you use one, I prefer a better option of straight through valves.
Hi,
Thanks Adam. Yes, the sand is very fine, to the extent that brushing it raises a dust cloud in the pool which then disppears. Sahara dust is an attractive option (in a way…), but this has been happening for about a month now - and we’re sufficiently far north (Tarn/Tarn et Garonne border) that we only notice African dust after a fairly major storm in the south. Also the sand always appears in small areas under the inlets from the filter - not sure why this would happen if it’s coming from above and distributed throughout the pool water?
Just been down to the pool to take a photo to illustrate - but the robot has very efficiently removed (or dispersed) all the sand. At least it’s easy to make it disappear!
Dispersed, that why I gave up on robots in most cases, people believe they are cleaning but in reality a day or so later it settles back on the floor only to repeat the exercise. Manual cleaning is more effective, especially if you get a cotton towel and scrunch that up in the skimmer basket. Along with a skimmer sock.
Is it then, actually sand, or run of the mill dust/dirt that builds up in pools - and, if they latter,
is perhaps your filter not up to scratch?
Because of the way water moves its quite common to see fine dirt deposit behind/under the return jet(s). Another reason why the side jet rolling action is best.