Sand filter... how much sand?

[zeltus]

Or rather, if it's cost-effective enough, how much zeolite?

I have a sand filter and I figure it's time to put replace it's contents. Is there a convenient way of working out how much sand/zeolite I need?

I mean, is it sold by volume or weight and in either case, how do I work out how much I need?

Many thanks!

Bill

[Poolguy]

Bill

As you have Gites then you MUST pay attention to the water quality, as I am sure you know already. The DDASS are very worried about the chemical balance in your pool water and have just released a paper in which they site their concerns about the Chloramines production in 'public' pools in France. Having tested 16,000 pools they find over half the pools give rise to concerns about this factor. (Article in today’s Figaro Pg 14) The full report is 300 pgs (I haven't finished reading it yet)

Now as you know, Zeolite can eliminate chloramines by the extraction of ammonia through ion attraction- chloramines are a waist product produced when Chlorine meets ammonia and are responsible for the ‘chlorine smell’ and most skin reactions in pools. There is usually plenty in the water of a family pool and even more in a Gite pool (1-5ppm). Zeolite is your best hope for keeping yourself away from the gaze of the DDASS; so to know how many kgs, you need to examine the side of your filter where it should have a decal showing the capacity of sand and gravel contained in your filter(s). Then you multiply this combined number by 0.65 to find out the weight of Zeolite (kg).

I understand from the DDASS that the frequency of change of filter media may soon be controlled but it is not clear how or when that will happen.

Andrew

 

 

[zeltus]

>to know how many kgs, you need to examine

the side of your filter where it should have a decal

That's the problem... there are no markings on the filter! It's not a plastic one, it looks like it's been woven out of fibre glass or some such. I was hoping that there was a rough and ready way to measure the volume of the filter container and take a percentage of that as the bit that represents how much sand I need.

Bill

[Théière]

[quote user="zeltus"]>to know how many kgs, you need to examine the side of your filter where it should have a decal

That's the problem... there are no markings on the filter! It's not a plastic one, it looks like it's been woven out of fibre glass or some such. I was hoping that there was a rough and ready way to measure the volume of the filter container and take a percentage of that as the bit that represents how much sand I need.

Bill
[/quote]

Woven that's posh! measure the diameter and height that should give a reasonable clue.

Andrew,

From my discussions with Dr Dryden the DDASS will be very busy looking at the commune pools for quite a while as Dr Dryden said from the ones he has examined in France they would be healthier pools if they disconnected the the filters completely!!! Trying to comply with the DDASS turnover requirements meant some of the pools inspected were trying to filter at 40m3 per hour! that's back washing speed!

[Poolguy]

Bill

Give me the diameter and/or the make and I'll estimate it for you. 'Spun fibreglass' filters are common for larger good quality makes.

John

Don't really understand what dryden is talking about (you know that there isn't much I agree with him about), most of the filters I was working on this year were pushing up to 100m3/hr or more, that sort of volume is very common for camping pools. But some of these filters haven't been changed for 20 years -That is the problem.

Andrew

[Théière]

[quote user="Poolguy"]

most of the filters I was working on this year were pushing up to 100m3/hr or more, that sort of volume is very common for camping pools. But some of these filters haven't been changed for 20 years -That is the problem.

Andrew

[/quote]

100m3 per filter/hour? or split between a bank of filters? that's not filtration that's jet washing the sand and passing most if not all of the crap back into the pool, seen a commercial pool filter sand cleaned and it was as good as new afterwards no rounding off of the sand grains and that was under an electron microscope, special cleaning process though.

[Poolguy]

No matee

that's just one filter ... this one is rated at 150m3/hr

                              [IMG]http://i584.photobucket.com/albums/ss285/andrewhenderson/P9223568.jpg[/IMG]

I changed to Zeolite on this one in March this year, and before next season I'll need to do the BIG ONE's ...... there is 3 of them and they do a whole lot more than 100m3/hr    

                            [IMG]http://i584.photobucket.com/albums/ss285/andrewhenderson/P9223561.jpg[/IMG]

 

Its not 'jet washing' its all about the surface area of media and the passage over the media in these filters is probably not much more than the domestic versions,- as you know Zeolite has 2000 times the surface area of sand (and crushed glass) because of its unique micropourus nature...   but you knew that.

salutè

Andrew

 

[Théière]

Oh big b*ggers, yep filtering at around 30m3/h/m2  that's still backwashing speed for domestic filters and still too fast for really good filtration, like pushing dirt through a sieve instead of allowing the dirt to form naturally into the filter medium but you can't just ask them to buy another [:)]