Pool filter issues?

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olive
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Pool filter issues?

Postby olive » Sat Apr 28, 2018 1:04 pm

I have been trying to whip the swimming pool into shape. It went OK to start with. PH level fine after reducing. Shocked with chlorine and it was Ok for a few days. Then went light green. Added Flocculant and got good amount of browny green stuff on the bottom and water was OK'ish. Started vacuuming and it has all gone downhill. I normally vacuum on filter cycle rather than to waste. Then I do a few periodic backwashes. It is now basically worse than when I started Just checked PH levels and they are fine. Chlorine is high.

I am thinking there is maybe an issue with the filter. One thing I did notice was there was very little suction on vacuuming. I am hoping that is as simple as a seal on the multi valve rather than a pinhole leak in the vacuum leg of pipework. I got more suction by closing the sink valve a bit more than in previous years. pressure valve on top of filter vessel works fine i.e. showing in normal range but when needs a backwash goes higher.

I am wondering if I have a broken lateral and or low sand level as there is debris below the water in to pool jets. Don't mind a bit of dismantling to fix anything. In ten years the filter sand down to nearly the laterals has been replaced maybe six years ago. Multivalve seal is 12 years old.

Anyone have any thoughts on subject or know how to test please?

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fyfin
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Re: Pool filter issues?

Postby fyfin » Tue Jul 03, 2018 11:15 pm

pool1.jpg
pool2.jpg
Well, I might not be much help but I have a similar problem. I had light dust in the pool that I couldn't get rid off so asked at the shop where they do pool stuff and also carry out repairs and pool maintenance so they know their stuff. They said I needed flocculant which I duly purchased. The lady said whatever you do don't vacuum as you normally do or you'll have a problem with the filter, vacuum, to waste. I didn't think until I got home and had put down the flocculant which did it's job well, all the dust now settled on the bottom and the water looking clear, that I didn't know how to vacuum to waste. I stupidly just flicked the multivalve to waste and quickly realised all I was doing was draining the water from the pool, no suction on the hose at all, obviously.
I then thought the only thing to do was do it as I normally do, it's only a small pool with no vacuum point so I put the hose in one of the skimmers and block off the other one. This seemed to work up to a point but the water was getting moved around by the circulation and although I was sucking up some dust from the bottom, a lot was just getting moved about and the water was soon as cloudy as ever, maybe even more so.
I gave it time to settle again and had another go but more or less the same. I'm leaving it overnight and will have another go but the lady was adamant that I should vacuum to waste but I don't know how. She said the flocculant would mess up the filter and I'd have to change the sand.
I have 3 levers and I know which position they should be in but I have no idea what they actually do. The middle one I was told by a pool guy is always in the closed position but if so then what is the point.
Sorry to hijack the thread but I see you had no replies and just wonder if not vacuuming to waste has caused you a problem. Maybe , me too but at least you know how to do it..
A man likes his wife to be just clever enough to appreciate his cleverness, and just stupid enough to admire it

TorreDelAguila
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Re: Pool filter issues?

Postby TorreDelAguila » Wed Jul 04, 2018 8:30 am

Fyfin,

When there's flocculated debris/dirt on the pool floor (i.e. the flocculant has done its work), it needs to be vacuumed to waste, otherwise it will be sent through the sand filter. This won't do the sand filter any harm, but, being very fine, it will pass through the sand filter and re-enter the pool through the jets . . . leaving the water all flocculant-cloudy again.

To vac to waste:
- couple up your vac tool as normal (to the skimmer point in your case)
- turn off all three taps, except the skimmer one (through which you are vacuuming)
- set the 6-way valve to Waste
This last will send the vacuumed grot down the waste pipe, and NOT return it to the pool.

When you are vacuuming to waste, the pool water level will drop during the process. A good idea to start with a well-filled pool, and/or leaving it filling while doing the job.

The three taps coming off the common pipe?
These provide a means of selecting where water is drawn out of the pool, on its way to the pump, the 6-way valve and sand filter.
One tap opens/shuts the main Drain for the pool (grille on the bottom, at any deep end)
Second tap ditto for the Skimmer(s)
Third tap is normally for a Vacuum point (which you say you don't have, so maybe this is the tap always closed)

A fourth tap is usually the pumped, filtered, Return to the pool, via the jets. Be careful not to have it closed while the pump is running, or the filter vessel can become severely over-pressurised.

For the future, find out what each of those three taps (1-3) do, by shutting off each one in turn. Shutting off the skimmer will be easy to spot. The 'always closed' one will likely be the (uninstalled) vac point. The third will be the pool drain.
Label each Skim, Vac and Drain. Fourth tap (on the right) is Return.

Hope helpful.
Chris

olive
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Re: Pool filter issues?

Postby olive » Wed Jul 04, 2018 8:56 am

Those three pipe manifolds are standard fare. I wonder what is further on from the valve that must always be closed?! Presumably no pipework.

Our pool is now fine for use from filtering and backwashing. The advice to vacuum to waste is sound. My concern would be over how much water ( availabilty rather than cost) this would use especially with the random movement of our auto machine. My observation is it spends proportionately more time in the deep end due to the current created by main drain being partially open . Maybe doing it manually - with a head on the end of a pole connected to vacuum pipe would be faster and thus more sparing on lost water?

I have put changing the filter sand and checking the laterals on hold due to injected jobs.

TorreDelAguila
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Re: Pool filter issues?

Postby TorreDelAguila » Wed Jul 04, 2018 9:06 am

Hi, Olive

Sign of a worn-out or broken lateral is normally filter sand repeatedly appearing on the pool floor, usually below the jets. The narrow slits in the laterals are there to allow filter water through into them, but to keep sand particles out - otherwise they get injected into the pool. Pack of laterals cheap enough (get the genuine branded ones).

Some sand filters get themselves refilled by owners/maintainers with just that - sand. This isn't good enough. The bottom section of the filter (to cover the laterals by about 10cm) must be filled with Sand Filter Gravel. This is coarse grit, that allows water to pass through it freely, and also provides the delicate laterals with protection from the weight of the sand, and the shocks that can travel through it. On top of the Gravel is placed the Filter Sand, usually to about 2/3 of the way up.

Vital that both these materials (sand and gravel) are "pool quality" (and of a known-good brand, eg Astral). In particular, the pukka sand is carefully size-graded, and doesn't contain the usual dust and fine particles, which will simply find its way into the pool.

Common for pressure shown on the gauge to be up at Normal when Drain and Skimmer are both open, and the system filtering normally. When Vac is in use, and Drain and Skimmer shut off (the usual arrangement for vacuuming), the pressure shown on the gauge will be appreciably lower, because the pump only has one source to draw on (the Vac line), and so indicated pressure drops. If the Vac suction is strong, then all is probably ok.

Vacuuming to waste is the preferred option where there is significant fine debris (eg flocculant, or even sand) on the pool floor. This stops it being re-sent to the filter, where it will pass through to the pool again.
Chris

TorreDelAguila
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Re: Pool filter issues?

Postby TorreDelAguila » Wed Jul 04, 2018 9:11 am

If you have a pool vacuuming robot, don't leave that on vac'ing to waste, or it will get though unnecessarily large quantities of water. As you say, best to do vac'ing to waste manually. When I do this, on rare occasions, an 8x4m pool level drops by about 7-8cm during the process.
Chris


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