Background first: my house is 28 years old and I've owned it for a year as of this past week. The pool is Gunnite with plaster finish (I think), original to the house, and I'm not sure how to describe the shape of it. Coffin-shaped?
The pool has one skimmer and one main drain.
You'll notice dead algae in the bottom. The pool filter I've got no longer seems to be doing a good job. When manually vacuuming the pool, it would get saturated enough that it would simply begin spitting the algae right back into the pool; a back-flush would bring it back into proper operation. But worse yet, it's leaking from around the multi-port at the top. When manually vacuuming the bottom of the pool a few weeks ago, I heard a little pop and spray. Looks like I shifted an O-ring at the top of my sand filter and it sprays water out when the filter gets full enough. It also appears that it used to have a pressure gauge, but the previous homeowner removed it at some point and blanked it off. I tried unscrewing the multi-port from the top of the filter to get at the O-ring and it didn't budge. So I'm pondering simply replacing it.
A shot of the setup.
The filter is a Tagelus TA-60 31 square-foot sand filter rated for 60 GPM. I have no idea how old it is. Modern manuals for the same unit - apparently a variant is still manufactured - say the manufacture date is the first four digits of the serial number in week/year format. Those digits are 6753 for me, so unless my filter was manufactured in 1953, then it's at least old enough that the statements I could find about manufacture date simply no longer apply. The multi-port isn't attached by a collar, but seems to be screwed in.
It looks like the lines out to the pool are 1.5" (I admittedly haven't measured them), while the lines for the equipment are 2" (I have measured them). Lines to/from may be 2". I'll check when I get the chance.
I need to do some yard drainage work around the equipment to make sure rainwater stops flowing by it. Then I want to build a box around it of treated lumber and fill it with gravel so rain doesn't splash mud up on the equipment. I may also build a small shelter. Depends on what my HOA says I can do. The electrical boxes are under the bucket; and while the boxes are themselves set up with weather-resistant covers, there's a break in the conduit to the pool pump that needs repairing.
On top of all that, I want to replace the filter unit and replumb some of this. I'm currently looking at Cartridge Filters. Sand filters are the easiest to maintain, but involve frequent back-washing that means I have to keep refilling the pool from my well. I like the idea of the cartridge filter and its "swap filter and done" possibilities. But that depends on which unit I get...
Which Cartridge Filter?
So as I can see it, I have two options for cartridge filters: single-element or multi-element. I've kept my search to Hayward, just because it's a name I know. Single element units top out at 200 square feet. Multi-element can get... big. With an 18,000 gallon pool, the minimum using the TFP-recommended math is 215 sqft. So 200 square feet would put me just under that.
At the moment, I'm still inclined to choose a single-element filter, however, such as Hayward's C200S. It looks like it's built to be very easily disassembled, with a simple latch-and-twist removal of the top. With a single large filter costing about $115, it's also financially feasible to keep two filters on hand and swap filters when one gets dirty. Then I can run the clean filter while I go clean the one I just removed. The downside of the low square footage is that I'll be cleaning it more frequently.
Jumping up to multi-element, I've looked at Hayward's C4030 425 sqft unit. With this size, I should be cleaning the filters much less frequently. The downside is when I need to do so, I'll need tools just to take the filter unit apart. The additional complexity means additional points of failure, too. A few Amazon reviews of the unit mention failing manifolds at the top of the unit, for example. A replacement filter set is $200 - $300.
Next plan is to replace the 90 degree fitting from the pump to the filter with more smoothly radiused elbows and try to do the same with the return from the filter to get rid of the extra bends in the pipe. Here's the order I'd like:
From Pool -> Ball-valve Cut-offs for skimmer/main drain -> Pump -> Jandy 3-way for waste -> Flowvis -> Filter -> Check Valve -> In-line Chlorinator -> Jandy cut-off -> Return to pool
Installing the Flowvis will help me be more accurate about my run-times to turn the pool over at least once per day. The Jandy 3-way will still let me pump to waste to drain the pool for the winter.
And I figure I'll attach unions to the pool lines directly to the lines to/from the pool so I can disconnect/replace/reorient the lines to my equipment as needed. Do you all think I'll have any problems with pressure causing the unions to give out and leak at the lines from the pool? The previous homeowner put rubber couplers on those lines and I've had to tighten them once already; and I can watch them momentarily bulge every time I shut off the pump.
As for the in-line chlorinator, I see strikes against using chlorine tablets. That and a floater are my current method. So I might have to abandon that idea. Switching to a cartridge filter means no more back-washing, and so my CYA levels would probably head skyward pretty quickly.
Thanks, all. Sorry this thread is so long! But please provide any and all feedback on these plans and let me know how I can do it better and do it right!