Cleaning the pool
September 28, 2017 5:03 PM

My father put in an in-ground pool about 10 years ago, but never kept up the maintenance. I want to clean it up for Summer but I need a checklist or something to work through because - oh god - this is an unholy mess and I have no idea where to start.

There have been no chemicals in that water for at least 5 years, possibly longer. It's "clean" enough that we get copious amounts of frog-spawn in it, then tadpoles, and then biblical plagues of frogs (and the things that eat them). We literally have had native tortoises living in it, and the local wild duck population use it as a toilet. The pool skimmer has gone missing - it might be on the bottom but I couldn't find it by poking around with the scoop.

This is a fibreglass in-ground pool about 4 by 6 metres in size. It was a low-salt pool and had a solar heater system (now totally destroyed, but that is a separate problem that I'll deal with later). The pump still works, and I have replacement filters for it that haven't been used. I can get more.

The water is a dark green, there's about a foot of silt and muck on the bottom, there's rafts of algae floating about, and the sides are faded and stained. It holds water so I believe the interior is intact.

Can I drain this thing, scrub it out, and do a water transplant? If so, how do I do that? What can I use to clean the sides down?

Or do I scoop as much shit out of the bottom as I can, throw chemicals into it and try to filter it clean? Again, if this is the best option, where do I start?

I have some money to throw at this but I'd prefer to spend most of that on getting someone to maintain it once it's cleaned and back to running. Currently I have a big net/scoop thing, a pile of brooms and brushes, an assortment of cleaning products, a high-pressure cleaner, access to plenty of tap-water and some time.

Where do I start?
posted by ninazer0 to Home & Garden (8 answers total) 1 user marked this as a favorite
I've done this a few times.

1. Scoop the floating stuff off the top
2. Scrub walls
3. Vac up the goop on the bottom using the drain setting so that the goop bypasses the filter. Be sure to stop before the pool passes 1/3 full or you are out of muck.
4. Refill with clean tap water (this might be expensive. Literally thousands of gallons....)
5. Shock pool if the water is greenish (while still refilling)
6. Repeat. Once the muck is gone you should clean with the filter. You'll need to backwash/clean the filter a lot.
7. Consider a pool cover to help keep the critters out

You'll need to do the above for a week or so until things stabilize. After 10 years the various hoses and tools are likely to be fragile/corroded and you should expect to replace a lot of it.

As long as you cover the pool, check the chemical balance, and do a quick vacuum/scoop pass every morning the actual upkeep is pretty easy.
posted by pdoege at 5:21 PM on September 28, 2017


Do not drain the pool all the way as it will likely 'pop' out of the ground (which would ruin all of the pipes and such).
posted by PorcineWithMe at 5:24 PM on September 28, 2017


I should probably also mention that it's very full at this point - nearly to the top. How much can I drain without being in danger of it popping? Half??
posted by ninazer0 at 6:44 PM on September 28, 2017


I probably wouldn't do more than 1/3 which would likely be less than what it would take to vacuum the sludge out (as pdoege said). You're probably looking at several cycles of partial water changes in order to get the pool really ready for chemical balancing. This is a project that will take lots and lots of hours and not a little cash.
posted by PorcineWithMe at 7:21 PM on September 28, 2017


I'm going to go a bit off the wall, but I would ask what else you have around the house/ in the yard that also could use some care. That pond scum is great stuff for enriching flower beds and if I had some I certainly wouldn't be throwing it away. If you have some nice free draining soil then I would scoop as much muck out of it that I can and literally dump it on the soil, working it in with a fork afterwards. I would do it with the algae on the surface as well. I see that you're in Aus so water usage can certainly be an issue so this is a way of killing two birds with one stone as it were.

After the bulk of the solids have been removed I would set up a simple soil filtration system with a layer of gravel on sand on gravel and set up a small aquarium pump to pump it to the top and have a cutoff when it is full and let it drain back into the pool. You can approximate this without a pump by pouring buckets of the water on top of the home made filtration system. You will need to periodically clean the top layer of gravel and sand, but it shouldn't clog that badly. After a week or so the water should be noticeably cleaner and will be ready for the shock/whatever you want to do to get it into a swimming pool and not a pond again.

The biggest flaw I can see in the plan is that the algae might grow faster than you can remove it in which case you would need to shock the water while the filtration setup is going on but after you've already taken out what you want for your garden. When properly running this should go through about 10 gallons in an hour or over 1000 gallons in a week and would be quite effective. To increase capacity I would add more filtration towers depending on the size of your pool. If you havent shocked the waste from this can also go right on the garden.
posted by koolkat at 6:40 AM on September 29, 2017


May I suggest, if it's at all possible, to try and get the frogs, turtles etc out before starting the chemical treatments. The less the better, as the chemicals will kill them.
posted by Crystal Fox at 7:24 AM on September 29, 2017


For the physical removal of stuff I can't help. But as for what chemicals to add once you have a mostly clean pool with plain tap water - I highly recommend going to a pool supply store to have them test the water for you.

A neighbor gave me a little pop up above ground pool this summer. I went down an internet rabbit hole for three hours looking up chemical formulas and expensive pool test kits. Our neighbor then told us they take a jar of water to the local pool/spa supply store and they test it and load up a box with all chemicals that you need, with a handy printout of what you need to add, in what quantities, and when. The paper was even color-coded.

The twenty minutes I spent on this (free) in store sample saved me about 8 hours of additional work research, trial and error, and buying toxic chemicals that I would then never use and have to pay to destroy.
posted by sol at 11:25 AM on September 29, 2017


UPDATE: this has all been put off as there appears to be BULK frog-spawn in the pool now. Everything will now wait until the pool is no longer froggy. We're girding our various loins for the influx of egrets, kingfishers and snakes who love a bit of cuisses des grenouille au naturel.
posted by ninazer0 at 5:28 PM on October 18, 2017


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