I use a 50/50 mix of chlorine 10% from pool supply and water, works very well. That’s basically the same concentration as 5% household bleach (unscented). We know chlorine is in the pool, so no unknown chemicals being dripped in. A pump sprayer works nicely and algae disappears almost instantly. Sure, some dead / dying algae drips into the pool so you might need to shock/SLAM pool to finish off chloramines. See pool school SLAM process here in TFP if needed, but I usually don’t need to. The pump sprayer wand may have trouble reaching upper girders even on a ladder so I started using a 2.1 GPM 12volt pump (old car battery works well) getting the 50/50 mixture from a 5 gallon bucket. So very easy! Larger GPM pumps like 5GPM cause problems with short cycling if using a long and small diameter hose. Some folks prefer pressure washing which of course avoids all chemicals, but there are a couple downsides to pressure washing, and you still get algae (live algae) dripping into the pool. Pressure washing also leaves some algae on the tops of girders so the problem comes back sooner, versus the chlorine which splashes onto the tops of girders and kills from above too, so the job seems to last longer than pressure cleaning. Also, I only had to slip with the wand too close a couple times, cutting the screens at the rail edge before I switched to the chlorine method. Older screens most vulnerable to cutting. Scrubbing can damage screens too, the chlorine mix makes that totally unnecessary. Alternatively, some folks swear by the “Spray-It-Forget-It” products, which claim to be a safer than chlorine. That product appears to work too, albeit A LOT slower - perhaps it takes days or weeks for algae to disappear, in my experience anyway. Reading the label even that Sprayitforgetit (Spray & Forget, Wet & Forget, etc) product advises to not get spray on plants, so I don’t know how safe it truly is, and we don’t really know what’s in it – plus it too smells chlorine-like and it’s rather pricey. Ultimately it drips something rather unknown into the pool. A downside to chlorine is that it may accelerate corrosion of certain types of metallic screws, so a good rinse with a garden hose is appropriate. My screws have the plastic heads but I still rinse the cage well, perhaps rinsing 15-30 minutes after the chlorine spray. Once per year keeps my cage rather spotless, maybe with an occasional touch-up. Of course there are many cautions when spraying chlorine. Proper attire is required, including a hat and goggles to keep drips out of your eyes and elsewhere. Avoid windy days. A mask with cartridges rated for chlorine will minimize inhalation of fumes. If not using a good mask, stay upwind. I cover all plants on the lanai and soak surrounding plants with water before and after chlorine use, still trying to minimize overspray.
Admittedly, folks with environmental concerns are not fond of such chlorine use. If you hire a typical firm that uses chlorine to, say, clean a concrete tile roof in order to avoid possible damage from a pressure washer (also controversial), the folks using chlorine will often use tons of product with associated major runoff. That leaves many customers with damaged lawns and plants. I do use the same chlorine spray method on my tile roof, but I walk the roof carefully with very minimal overspray and minimal product use – almost no runoff into gutters. The chlorine rated mask is doubly important when walking the roof and again try to stay upwind and on a non-windy day. Passing out with lung damage is one thing, falling off the roof another. I use the same process for lanai pavers, driveways and walkways, since pressure washing drives all the sand out of paver gaps and makes a huge mess. But I guess I’ve drifted from the pool cage topic….
Speaking of damage, pump sprayers and cheap diaphragm pumps don’t like chlorine either. I fully rinse them but pump sprayers like to corrode and maybe you get 3-5 uses, maybe disassemble and coat with MagicLube to get a few extra uses out of it. Same with the diaphragm pumps – I run water through it for a long time, emptying one or two 5 gallon buckets (into the pool) as a rinse cycle. But after many uses the diaphragm must be replaced. $70 for the Everflo pump on amazon, $13-$20 for a new fimco valve assy from pwmall. No need to spend much on hose, I repurposed the (1/4 ID I think) plastic hose from the coil of it (30 feet?) you find in an old broken refrigerator
If you happen to have a market umbrella or other furnishings that use Sunbrella fabric, the chlorine mix cleans it well. Other fabrics are ruined by the chlorine! Some day if I’m feeling humble enough I’ll post my security video of me using a pump sprayer while walking the ledge of the spa, stepped into the waterfall and landed in the pool. I think that was when I switched to the motorized pump
Hope that helps – happy cleaning!
