There's a large concrete swimming pool at my mom's house that needs
refurbishing, and I'd like to help her bring it back into use. Drain the
water, clean out debris, acid wash, ok sounds relatively simple and cheap so
far. Except the part I'm worried about is the filtration system. It is
very old and rusted in the pool room and I doubt it works. So I can better
"visualize the cost" of this project and keep the cost manageable I figure
I'll use a pool cleaning robot instead to suck up leaves and dirt that fall
inside. But can these things do the whole job in a large pool? Can they
keep up with keeping the pool clean without excessive maintenance? What is
considered the best model these days as a filter system replacement?
I can't help you much but I'm interested in the answers.
But, off hand, it "seems to me" that several of the "hang on" systems used
for those relatively cheap above ground pools combined with the robot to
sweep up the bottom would provide essentially the same coverage as a pool
with build in drains to a central pump/filter house.
Since you are talking "large" you are definitely beyond using the throwaway
filters. You want/need sand and/or diatom filters. I believe I have seen
sand filters for larger above ground pools so they may be your answer. When
you have extra use, you can run the 2nd/3rd filter and when the party is
over you can clean the most used filter.
In the filter game, it's usually better to run 27/7 with a small filter than
"cycle" a larger filter. You may well find that only running one
pump/filter (w/robot) keeps you water in good conditions.
I assume you attend to the chemistry of the pool.
Start there, see if it works (remove the doubt) and then fix anything
broken. Get the model number and try to locate a service manual for
the filter system.
You need both the filter and the robot.
Call Mom on Sunday....
While the pool "robots" are much better than the cleaners than attach to
the suction side or pressure side of the pump (or that have a dedicated
pump) they can't filter that much water.
I have the Dolphin. It was $800 with the caddy, and that was with a 20%
off at Leslie's. Leslie's is a good place to buy it because they offer a
longer warranty on the Dolphin. Mine broke like a week before the
warranty was up and it was repaired free.
On my pool, all the water for the filter goes through the skimmer, the
drain in the bottom doesn't work, so I needed the better cleaner.
Installing a real pump and filter isn't that hard or expensive as long
as the plumbing from the pool is okay. If you're good with PVC and
wiring you can do it yourself. Just plan the PVC arrangement so that the
pump is removable/replaceable in the future.
I'm pretty good with DIY basic pipes and electrical, so I'd be inclined to
replace all the rusty pool room equipment rather than worry about the
maintenance even if I could get it to hobble along after flipping the
switch. There's a large heater box with a roof vent (don't need one for hot
California summers), a large cylinder with a pressure gauge which I remember
from childhood always needed a lot of maintenance, I think this is called
the DE filter, and a maze of metal pipes. So let's suppose I just remove
all this equipment from the 1950s-70s. Would this filter room equipment
cost me thousands to replace? Does it get very "technical" to install like
for example installing a central air conditioner? Is the filter room
technology much better these days and less maintenance than it was 30 years
ago? The pool dimensions are 18' x 37' feet and deeper than most pools I've
I don't think new equipment is much different from the old. Wiring methods
and materials have changed though. I think you need to decipher what you
have, and how it's connected, then you'll have a better idea of what you may
want to replace it with. Flexible non metallic plumbing makes the job
considerably easier then what you may have existing.
I guess you didnt get stuck doing pool maint as a kid, like I did.
I would suggest calling a pool service & telling what your situation
is. Some of the better ones could easily give you a very good idea of
the costs involved.
Mercifully, I sold my old 1950's/1960's house (the OC) with a pool
before I had to pop for all new pump & DE filter.
I owned the house for ~15 years and had the same pool guy all that
time. I had the pool re-plastered & re-tiled but kept the coping &
deck. When the original DE filter started to leak, my pool guy had
a used unit that another customer had replaced with new. He installed
it for me at a small fraction of a new unit and I sold the house a few
My guess is that your pump & motor are probably fine and hopefully all
the plumbing....if anything your just need a new DE unit.
Filters are sized based pool volume.....looks like oyurs is in the 20
to 25k gallons.
Since you're stuck with the pipe sizes......IF oyu need a new pump, it
has to be happy with the existing plumbing. Once oyu have a pump size
oyu can choose a filter size.
If the original pump & filter arrangement kept the pool adequately
clean, then thats a good starting point. Depending on the age of the
equipment, the pump & filter might be undersized by today;s specs.
When we had my parents pool filter system replaced the pump & filter
were both upsized about 50%. The old system worked fine as did the
new one....we just minimized pump time consistent with a clean (low
If you;re in central OC (Tustin or Orange) I can recommend my former
If you;re in central OC (Tustin or Orange) I can recommend my former
Excellent info from all. Bob, my mom is also in OC so would appreciate the
referral to your former pool guy. My email is scorpionleather fancy symbol
Leslie's pool store was mentioned. My local store has "mock-ups" of
pool filter systems. Find the gallons of water in the pool (figuring
the depth also). The web has calculators , but I don't have one in a
IIRC, the install was free but just ask them. CA has 137 Leslie's
I called Leslies service dept and the first thing they asked me was how old
the pool is, whether the existing water is clean, etc. Then they said "it
needs to be re-plastered" - based on what I told them on the phone.
But the existing plaster looks fine as far as I can tell visually. Should I
be concerned with plaster for this project? I just want to make it
swimmable, not a showpiece. Is the downside to keeping the existing old
plaster that it will slowly lose water or something else related to
chemistry? If I have to replaster that would be way out of my affordability
to help my mom fix this thing up.
Focus on the filter and robot repair. I have some plaster problems,
the pool is 12 years old. Minor but costly in just doing patches. My
11K gallon pool should really have a new plaster surface. Postponed.
Plenty of info here about resurrecting a pool.
Actually it's new plastering that affects the chemistry.
Once you drain it you can acid wash it and repaint it if it needs it.
Leslie's sells the paint. Replastering will raise the cost by about
$5,000 in California for simple plastering, and by $9,000 for a pebbled
surface, without new tile or coping. You can look at the surface and
tell when it's all pitted and needs re-plastering. In Florida, where my
brother has a pool, re-plastering is only around $3000.
I know that when my pool's plaster was hopelessly pitted, it was also
very hard to keep the algae in check, but maybe that was for other
reasons than the pitted plaster. Back then, the pool stores were pushing
stabilized tablets and granules very hard, without fully understanding
how the stabilizer acid slowly built up and required higher and higher
chlorine levels to keep algae in check, they call it "chlorine lock"
where the cyanuric acid ties up free available chlorine. I drained and
refilled just a year ago, and already my cyanuric acid level is above
the optimal level (but below the maximum level) so I'm laying off the
tablets for a while until enough new water dilutes it. I've been in
Leslie's a couple of times to get my water tested, and have had people
in front of me get the advice to drain the pool to get rid of the
cyanuric acid. There is no neutralizer available on the market any more
(there was one for a while but it had side effects that were worse (and
more costly) than just draining and refilling).
Also, remember to factor in the cost of the electricity to run the pump.
Those pumps use a lot of power, and you have to run them many hours a
day in hot weather.
I wanted to take the pool out rather than re-plaster it, but that idea
was vetoed by SWMBO. Taking a pool out isn't all that cheap either.
I would definately verify that the equipment is faulty before replacing it. It
would probably be worth paying someone to do this if you can't figure it out
yourself, just on the chance that the equipment just needs cleaning to work
By the way, I always assumed that the pool robots just ran off the pool filter
suction, and that they wouldn't function on their own. (I own a spa, not a pool,
so I've never used one)
The DE filter may just need the earth replaced (there is a better
compound to put in there than DE now). Otherwise, replace it with a
cartridge filter. Be sure that you don't get too small of a cartridge
filter system or you'll be endlessly cleaning it. When we bought our
house it had a Sta-Rite filter with a single cartridge, and I was
cleaning it every few weeks, with the current filter, a Pentair with
four cartridges, once per year is sufficient, and probably with a single
larger cartridge it would have been fine as well.
You need to wire it properly with all the GFI stuff since the pump is
likely 220V. Add an Intermatic mechanical timer.
Probably $600-800 for a filter, $500 for a pump, and another $100 for
plumbing and wiring. You might find some of the stuff on craigslist as
there are a surprising number of people that remove their pools (I got a
pool slide that way), and I've seen other pool equipment for sale as well.
You'll likely need to buy PVC at an irrigation supply house to get the
2", 2.5" or 3" fittings and pipe, the selection at Home Depot is
limited. Not sure where you are, I get my pool PVC stuff in Campbell, CA.
So let's suppose I
Sounds like my pool, which was built to accommodate a diving board, and
is about 13' deep in the deep end, which you don't see on new
construction home pools. My pool is about 40,000 gallons.
You might also consider plumbing in a chlorine tablet feeder (don't get
the Hayward) but beware of chlorine tablets because cyanuric acid from
these builds up requiring pool draining to get rid of it. Liquid
chlorine is more hassle but causes less problems.
...good info, thanks!
I turned on the switch briefly and I could hear the pump motor run! The
pool room has the following equipment:
Nautilus NS-48 DE filter tank (probably ok, a bit of corrosion on the
Aqua-Flo pump with Gould E-Plus 8-151782-02 motor (turns on ok)
Wahlds pool heater (severe rust, probably doesn't work, also rarely used it
when I was a kid)
If I take on this project "at the bare minimum" what I would have on my
Empty dirty water and acid clean plaster (found 3 bottles of muriatic acid
in the pool room)
Fix crack running down side of pool
Refill pool and flush out debris from lines
Replace burned out underwater light
Replace pump mechanical timer on wall (rusted out)
Replace any worn parts inside DE filter (seal, filter fabric?)
No re-plastering for now.
I wonder if I'd run into an expensive surprise or if this could turn out
No. Most robots rely on the filter system of the pool, for "power"
and filtering. Those equipped with "filters" aren't going to filter
very fine particulate.
Whatever worked in the past, usually.
I looked at an *old* pool that was @25x50x10' with a real "deep end".
The "pump house" was a good 100' distant.
As I think I understand it, the height of the pump relative to the
waterline and outlets are of consideration.
No they do not. The simple pool cleaners use either suction or pressure,
via a hose and the pool's pump (or an auxiliary pump for some) but the
robots do not have any plumbing. The robots are powered by a DC power
source via a cable.
The robots do a much better job of cleaning, especially for sand and
dirt. When I had a Polaris cleaner it picked up leaves just fine, but
finer pieces of debris like sand when right through the collection bag.
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