Is the pool swamped? That is, does it have a pretty thick coating of algae and other organic debris?

Slide valves are not normally used with sand filters. Multiport valse are the norm. Most folks with multiports would vacuum using it's waste setting with a swamped pool. You don't have that available.

Normal pressure should be between 16 and 18 lbs with a 1 or 1-1/2 HP Hayward, Speck or Pentair pump. Is the pressure gauge working correctly?

During filtering, is the water in the pump basket moving quickly with a minimum of air?

Scott

Scott, the pool is not swamped. It is very cloudy but not much organic debris.

I will have to check the operation of the pressure gauge.

The water in the pump basket does seem to move well, and there's very little air visible.

Are you sure it is plumbed correctly?

When you did the sand change, did you add pea gravel? Water should be added first to act as a buffer. It prevents breaks in the laterals and manifold.

When you changed the O-Rings, did you notice if the walls of the main tube were scored, allowing unfiltered water to blow by? Any looseness or stickiness in the plunger?

WRT the cloudy water, was it caused by improper chemistry, metals in the water or phosphates? Get it tested!

Scott

Scott, I'm confused by your question about pea gravel. I followed the directions provided by Hayward to change the sand, including adding water to buffer the sand, but I haven't seen anything that says pea gravel should be added to the sand. Can you clarify?

I saw no evidence of scoring in the valve body, but the plunger is definitely 'sticky' when I move between the positions. Is this an issue, and if so, what needs correcting?

We do get the water tested weekly, and it continues to show OK. From what I can tell, the cloudiness is caused by the dirt getting recycled from the filter back to the pool.

Thanks again for responding.

Many techs put some pea gravel in the bottom, just enough to cover the laterals. It helps keep sand from blowing into the laterals, helps prevent channeling in the sand bed , and helps disburse the flow of water more evenly when back washing but it isn't a requirement,

If you checked the pressure gauge and it seems ok, check the impeller. It may be clogged. This can happen with cracked pump baskets.

Turn off the pump.
Remove the lid and pump basket.
Reach your finger in the hole deeply until you reach the impeller's hub. Wiggle your fingers around, d you feel any eaves or other debris?
If you do, pull it out, bit by bit.
If the pump basket is cracked, get a new one.
Put the basket in, add some water, and start the pump.

I think you'll see a big jump in pressure. That increase will mean a LOT more water is moving through the filter. It also means that the cloudiness was likely caused by a poor filtration rate.

Scott

Scott, with your help I seem to be homing in on the problem. I opened up the pump because I couldn't get my fingers to feel the impeller, and although there was no debris I did find that the large O-ring on the impeller cover inlet was missing, which is probably a big contributor to the low pressure. Additionally I found that the impeller cover is cracked in several places where the plastic is worn to almost zero thickness, the brass ring at the cover inlet is very corroded, and the impeller is scored. Can replacement parts be purchased? Unfortunately I can't find any brand or model info on the pump, so I would have to bring the parts in for visual match-up. Finally, how do you get the impeller off the motor shaft? Is it a press fit?

Thanks for all the ideas and guidance!

Found out today that the pump is a Sta-Rite P4, and that parts are available. Still need to figure out how to get the impeller off.

On the back of the motor, pry off the center cap with a small screwdriver. That will expose the shaft. It should be slotted. Using a wide blade screwdriver to hold it, you should be able to spin the impeller off. It's threaded onto the other end of the shaft.

The pump may be better known as a Max-E-Glas II

Scott

"Slide valves are not normally used with sand filters. Multiport valse are the norm."

Scott, I just read this thread and wondered -- now that azroyal is working on his pump, should he look into changing out the slide valve for a multiport valve while he's at it? If so, how involved/difficult would that be?

Chahnging to a multiport would be some simple plumbing changes because the intake and return ports are in different locations. assuming the existing plumbing has enough space between fittings to be cut and extended to the new multiport.

Scott

Follow up to last postings - after repairing the pump we saw some improvement but still have the same issues: filter pressure is still too low and the darned filter still spews dirty water back through the returns upon start-up and when vacuuming. At this point I'd swear that the slide valve must be allowing input water to bypass the filter, but I've taken it apart several times and cannot see any evidence of damage or other issue. A pool tech has been called; hopefully they can identify the problem...

hey azroyal
i feel like i was reading a book and someone tore the last page out - i hope your problem is solved and would love if you shared the outcome with us...

I have a Hayward pool with a 24â Foxx filter by Baker Hydro. The time has come on my watch to replace the sand and I was considering glass beads as an alternative. However.... there is a problem with quantity. The filter instructions say 3 cubic ft (300lb) of #20 Silica sand. We work in Kg over here so this equates to 136Kg (.084 cubic metres). Now, given #20 Silica sand is ~ 2.65g per cc (2650 Kg per cubic metre), .084 cubic metres equates to 222Kg. You see the problem? Do I put in 136Kg or 222Kg? It makes a significant difference considering the price of glass beads. Can anyone out there help?