Lay My Hat

I am considering changing my pool filter from sand to glass and, following recommendations from Teapot on here am looking at using Bayrol AFM (aka Dryden Aqua AFM). When enquiring to find a local supplier one of my local independant suppliers made a couple of points that I would be interested to hear from experts on here what their views are:

1. You need around 15% less glass by weight than sand, I assume this is due to lower density of the glass media.
2. If using glass you mustn't use flocculant otherwise the glass will turn into 'concrete'.

Point 1. ties in with a supplier who said I would need 189kg of glass to fill a filter that would use 200kg of sand.

I dont really understand the logic of glass turning into concrete rather than sand.
The concrete I have mixed on numerous occasions has used sand and gravel not glass ! Oh and I used cement which is not a known pool floculant

As above.
Sand + aggregate + cement + water = concrete.
Flocculant + glass? Certainly not concrete but maybe he was analogizing - mineral hardening possibly although I've not personally seen anything as drastic as 'concrete' & we have awful water quality locally at present.

I also didn't understand why glass would be more likely to solidify (which is what I think she was suggesting, rather than literally turning to concrete) than sand, hence the reason for posting here.

Aren't you supposed to try to keep flocculants out of any type of filter for this reason?

Yes, definitely. Vac direct to waste only on clearance but a nominal amount will almost inevitably find its way to the filter on reboot.

Well it just shows theres something new to learn everyday,. I never knew that about flocculent, luckily I have never had to use any. Just a thought, would multi-function tablets contain a flocculent?

I have just replaced the sand with glass in my pool filter. No idea re weight i just topped it up to the old level. Best tip having scopped out the sand before by hand is buy or borrow a wetvac. I bought a karcher wetvac, the one with 22l capacity, its now a 2 hr job not a whole day.

So having replaced the sand with glass the suction on vaccing is far better, i reckon theres a few hours per day less pump hours needed per day so maybe a payback on the 150e cost of sand.

Thats good news gardenboy, I must admit that I am not looking for emptying the sand, but I have to wait for the nesting bird to leave before I can get in there the pool house.

Dusty wrote:
1. You need around 15% less glass by weight than sand, I assume this is due to lower density of the glass media.
TRUE


2. If using glass you mustn't use flocculant otherwise the glass will turn into 'concrete'.
TOTALLY False. Another idiot pool shop! Using a good flocculent in the correct way with AFM it will remove sub micron particles and chlorine use will drop even further. Part of Dryden's Daisy system.

Point 1. ties in with a supplier who said I would need 189kg of glass to fill a filter that would use 200kg of sand.

You will be paying the Bayrol premium price, I could get a quote for shipping to France?

RichardHenshall wrote:Aren't you supposed to try to keep flocculants out of any type of filter for this reason?

No, once the floccs have formed you want to gently remove them in the filter. The way most pool people use flocculation is wrong but leads to bigger sales of flocculent, surprise, surprise.

gardenboy wrote: So having replaced the sand with glass the suction on vaccing is far better, i reckon theres a few hours per day less pump hours needed per day so maybe a payback on the 150e cost of sand.

This approach is predictable and wrong. Far better to slow the filtration rate down and run for longer. Moving water is healthy water.
My Eco setup costs less to run for 24 hours continuously than a standard setup does for 2 hours. That produces better cleaner water and saves a huge amount in electricity. Slower filtration is better filtration!

Just out of interest, what amount of sand do you need in the filter. The reason I ask is that we’ve had to do a lot of backwashing- partly due to guests literally slathering on sun cream. The filter now looks very clean Do you ‘lose’ some sand when you backwash and if so how much should you top it up with?

SW31 wrote:Just out of interest, what amount of sand do you need in the filter. The reason I ask is that we’ve had to do a lot of backwashing- partly due to guests literally slathering on sun cream. The filter now looks very clean Do you ‘lose’ some sand when you backwash and if so how much should you top it up with?

Varies on size/model but you should have a manufacturers plate/label to indicate volume & I stand to be corrected, but I didn't notice much by way of significant sand loss on a recent empty/refill & it was 5ish years old, regularly backwashed/rinsed.
My own model took 220 kilos so not something to relish on a regular basis in an underground plant room. I have since noticed a marked improvement in vac suction & a noticeably quieter pump. Related? I'd guess so but per teapot & gardenboy, I too would look to source quality glass media for any future clearouts.

Surely improved suction equates to reduced filtration. It may make lifting larger leaves etc easier but the finer particles will initially just go straight through the filter. It's the build-up of finer particles that improves filtration.