Purchasing a new AG Pool. Need advice...

[Watermom]

I would buy a sand filter but that is just my preference. They are by far the easiest to maintain. However, you will find just as many people who will tell you to buy a DE filter or a a cartridge filter. DE filters provide the best filtration. However, I have never had any issues with my sand filter not filtering well in all the years I have had a pool. All of the moderators on this forum have sand filters, too. My opinion is that I wouldn't want a cartridge filter because of the hassle of cleaning them. But, some of our members love theirs.

An SWCG does allow for less frequent "fooling with" your pool BUT most AG pool warranties are voided if you add an SWCG.

Others will chime in with their opinions, I'm sure. Hope this helps maybe a little.

[Serapium]

Definitely helps! Bonus is that I'm already familiar with sand filters. How about the pump question? I know I don't want to overpower the filter with too big of a pump, and in my 15' AG pool my 1 HP pump was more than enough to circulate water through the whole pool. A 33' pool is a much different monster. I know I'll have to run the pump much more often to achieve enough water turnover through the pump, but will a 1 HP pump even move enough water for adequate circulation all the way to the other side of the pool?

[PoolDoc]

A 1HP inground pump is MORE than enough for your pool: a 33' x 52" pool only holds around 22,000 gallons. Optimal MAXIMUM circulation is around 60 GPM, but you probably want more like 48 GPM.

A combination like this:

Hayward S244S Pro-Series 24-Inch Side-Mount 1-1/2-Inch Vari-Flo Valve Pool Filter @ Amazon
Hayward Super Pump 2-speed 230V w/Switch @ A1PoolParts

would work exceptionally well and be very efficient to operate. You would leave the pump on low speed except when vacuuming, backwashing, or cleaning up, and you would definitely want the smaller pump!

But, I'm not sure if you are planning to use an IG pump and filter.

[aylad]

If you're talking about 33' round, depth 48", then you're looking at about 25,600 gallons, which is roughly the same volume as my pool (mine is 18 x 36 rectangle). I have a 1 HP pump and 300# sand filter, and it works just fine for me.

[PoolDoc]

If you're talking about 33' round, depth 48", then you're looking at about 25,600 gallons.

??
radius squared x pi x depth x gal/cft
15.5*15.5*3.14*4*7.48=22,571

[aylad]

bleachcalc volume calculation......

Janet

[PoolDoc]

Another error, in it then.

[BigDave]

??
radius squared x pi x depth x gal/cft
15.5*15.5*3.14*4*7.48=22,571

I'm so sorry to contradict, but I must respectfully point out that half of 33 is 16.5 and that (33/2)^2*Pi*4*7.48=25590.534.
15.5 is the gallons in a half-barrel. Is it the weekend yet?

[Serapium]

Thanks for the input! I know that a 1HP pump is capable of circulating enough water to filter the volume of the pool... I guess what I'm actually wondering is if the filtered H2O coming out the return to the pool comes out with enough force to circulate water evenly throughout the entire pool. In other words, with a 1HP pump turning over 30K gallons a day, are you really filtering 30K gallons, or are you filtering 10K gallons three times?

[PoolDoc]

@ Janet, Dave: my bad! sorry! (thanks for the correction!)

@ Serapium: what actually happens when you circulate water is mind-numbingly complex, but roughly you can think of it like this:

UP: unfiltered water in pool
CP: clean filtered water in pool
UF: unfiltered water in pipes
CF: clean filtered water in pipes

1. Initially, the system pulls UP into the pipes, pushes UF through the filter and discharges CF into the pool.

2. But, now the pool contains UP + a small amount of CP. There's a lag in mixing -- how much lag depends on the way the pool returns and drains are arranged. But anyhow for the next few minutes, the system continues to pull ONLY UP from the pool, and return only CF to the pool.

3. But, then, the system begins to pull a mix of UP and CP into the system, so the filter NOW is filtering water that is mostly UP, but contains a little CP. CP has ALREADY been filtered, so that's pretty much wasted effort.

4. As time goes on, the system pulls an ever decreasing amount of UP into the pipes and more and more CP, wasting more and more of the filtration by filtering a mix of UF and CF.

So, even though a 100GPM system can filter a volume of water EQUIVALENT to the volume in the pool, in only 1.7 hours, it will take MUCH longer than -- probably at least 10 cycles before 99% of the water in the pool has been filtered 1 time.

For a typical pool with side inlets, a main drain, and skimmers and an 8 hour turnover rate, it will take around 3 days to filter 99% of the water. Commercial pools, with laminar flow floor inlets and primary circulation through skim gutters can accomplish the same task in just one day. And, I've actually worked with one pool with this design: it was MUCH faster to clean up, then pools with more typical piping systems.