Using a Nature 2 system with the BBB method

[aylad]

The sand doesn't need to be changed, unless you were previously using Bacquacil or some other chem system that goops up the sand. But if it's a chlorine pool, and has always been, then no need to change it. One of our mods, Poconos is going on 14 years with his sand, and I think Watermom's at 11 years with hers.

If the pool is blue/cloudy, and you're not losing chlorine when testing at night and again before the sun hits the pool in the morning, then most likely the algae is dead and just needs to be filtered. Assuming your filter is working properly, you can also add a handfull of DE to the filter to help catch finer particles. If you're still losing chlorine overnight, however, then you're still fighting something in the water.

[PoolDoc]

If it's green, it's not dead.

If it's brown powder, it could be dead algae. Or, it could be something else.

[tdkorson]

Been brushing, filtering, brushing, for a few days now. Regardless of any other problems I might have, it seems that the filter is not working properly. When I vacuum the pool, the supposedly filtered jet of water back into the pool is very very dirty. It seems as though I'm just circulating the dirt and dead algae.

Also when I backwash, the water in the glass jar does not seem very dirty. Any ideas?

[PoolDoc]

it seems that the filter is not working properly. When I vacuum the pool, the supposedly filtered jet of water back into the pool is very very dirty
. . . .
Any ideas?

Pretty much what you think: repair or replace your filter!

[tdkorson]

OK, but what can go wrong with a simple sand filter? The top controls seem to function correctly - nothing seems mechanically broken. I asked about changing the sand earlier and the reply was that sand lasts forever - so what is there to fix? What possibly could be wrong?

Is there any repair I can try other than just purchasing a new filter?

[PoolDoc]

+ Your sand may be gone, typically because the filter is too small for the pump, and you've blown it out during backwash.
+ You may have coarse sandblast sand in your filter, instead of properly sized filter sand.
+ Your pump may be much too big for the filter, and is blowing the dirt through sand -- if your CLEAN filter pressure is over 15 - 18 psi, this is likely.
+ Your sand may be clumped from sun tan lotion, Baquacil or other contaminants, allowing bypass channels to form.
+ Or all of the above could be true.

Since your builder (I assume) sold you a Nature2 unit, the 'bogus-ness' factor of your equipment set up is likely to be high.

[tdkorson]

Thanks. So I guess my next step is to take the top off the filter and see what is going on inside. I'll have to cut some plumbing, so I need to head to the hardware store first. In the meantime:

My "after backwashing" pressure runs about 10-12 psi. Does that sound about right?
My filter is the Hayward s-244T with effective filtration area of 3.14 sq ft, a filtration rate of 20 GPM/sq ft, Filtration and backwash design flow rate of 62 GPM, maximum working pressure of 50 psi; holding 300lbs of sand.
My Pump motor is the 1 HP A.O. Smith 1081 design ST1102 single speed motor
Are the motor and filter sized right for each other?

[PoolDoc]

Yea, the Hayward S244T design sucks -- the sand bed depth is too shallow. 15 GPM / sft is optimistic on that filter; 20 is ridiculous. Your filter pressures would be OK if everything else is, but if the sand's mostly gone, you'd get those low pressures just because there's nothing there to create resistance.

The good news is that it's really easy to work on, just tedious with all those bolts.

Your pump performance is determined by the pump, not the motor -- you need the pump M/N rather than the motor M/N

[tdkorson]

Also, the pressure on the filter does not seem to rise much even after 24 hours of filtering filthy water