If I looked at the sand in the filter, what should I see?

[aquarium]

Why was it compacted? Dunno, maybe that's just what it does eventually? Probably was never properly backwashed in its early years.

I went ahead and turned it to filter, no grey cloud into the pool, so that's good.

Before I replaced the spider gasket the system ran at about 12psi, because it was leaking water around the gasket. With the new gasket but before cleaning the sand, it jumped up to 18psi. Now with the sand cleaned it's running at 15psi.

TW

[aquarium]

Been running it 24/7 the last three days as I do the alkalinity adjustment thang. Stop and backwash each day for a minute or so, get a short burst of grey water each time, so that seems to be working better.

One other thing that struck me about the compacted sand - Since the spider gasket was blown the path of least resistance during a backwash might have been to bypass the filter, so even when set to backwash there was little actual effect.

TW

[matt4x4]

I believe you got it right there with the path of least resistance - it just went to bypass.
WRT the sand compacting, I believe this happens because many people don't know better or ignore recommendations, however, most pool owners i know are adding all their chemicals through the skimmer since it is teh most "convenient" location.
Now, if you add your bleach that way, it likey will not do anything to your sand, however, floculant could easily clump your sand particles since it's designed to clump fine solids. Other chemicals may also have similar effects, algaecide comes to mind (really, why bother mixing it in a bucket first, isn't blowing it out the return pretty much the same thing?).
If sand can last 5 years+ without compacting and solidifying under noraml use, what makes 7 or 10 or 20 years so different, it has to do something with the chemicals that get put in pools.
I believe adding anything through the skimmer is going to shorten the life span of your equipment to some degree.

[Rangeball]

Matt, assuming you use bleach, do you add it through your skimmer?

If not, how?

[waterbear]

I have stated on other posts (and got blasted for it) that sand filters need yearly maintenance to keep the sand clean and in good condition. Backwashing removes the dirt from the filter but does not remove the gunk and clear any channeling or clumping of the sand! Water is going to take the path of least resistance whether you are filtering or backwashing!

To break up the clumps and flush out the sand open the filter to expose the sand and stick a garden hose in it. The sand will loosen up and the water will overflow and carry any dirt and debris. If there are any clumps break them up (a broom handle is good for this but be careful of the laterals or you can break them!). When the sand is clean, free floating in the water, and has no clumps you can stop flushing it and reassemble the filter. If the sand is really dirty or calcified you might want to use a commercial sand cleaner on it.

BTW, Thank you for making my point. I hope the proper people get to read it!

[aquarium]

To break up the clumps and flush out the sand open the filter to expose the sand and stick a garden hose in it. The sand will loosen up and the water will overflow and carry any dirt and debris.

This is a good idea. Even after having opened the filter three times already, stirred the sand by hand and done several backwashings, when I used a garden hose it stirred up a lot more 'stuff'.

It would have taken too long to let it run clear, so I put the top back on and then immediately backflushed. The water ran cloudy for much longer than it ever has before, so I guess I got most of it. The sand looked 'right' this time, so I think this beast is finally tamed.

Other than fixing this sort of problem, it seems to me that sand could not ever really 'wear out', correct?

[waste]

Aquarium,congrats on getting it taken care of sucessfully!
The sand can wear out, however it takes a long time. Actually slightly dirty, or aged sand, filters better than new, the pathways between the individual grains gets smaller either due to the dirt it's already collected or because the edges get erroded so the sand can 'snuggle up' a little closer to is fellow grains - this allows smaller particles to be trapped. Well cared for sand should last 10 + yrs.

[matt4x4]

Rangeball, I have a couple ways of adding bleach to the pool, the preferred method is to walk around the pool gently pouring the bleach in about 2' from the wall (as far as you can reach over).
The second is to pour it into the skimmer and let the pump blow it out and circulate it, this is only used when my wife is standing by the car wondering why we haven't left yet, tapping her foot on the ground.
I don't really worry about that second method too much since my plumbing is non corrosive and bleach really does nothing to your filter WRT clumping/channeling etc.

Oh BTW, waterbear, nice sand filter cleaning instructions, IMO, dirt will eventually get all through all your sand since there's no way it could ever just lay on top, since some people dump everything in through the skimmer, that dirt and sand wille eventually bond through all the floculant and other chems introduced through the system. Obviously, your method helped clear up an issue quite well. Mine's on year 3, and still working well, but how will it work after 5 or 7 years.......I'll keep your instructions in mind for future reference.