Useful Information for Homeowners in Mexico on Repairs, Plumbing, Electrical & Maintenance

May 20, 2023:
There are many basic things about Mexican home construction, Mexicab home design, & home maintenance that don’t seem to be documented on the Internet. This article serves as a repository for some of the answers to these issues, that I keep rewriting on expat forums over the years.


Re How to Stop Algae from Growing in Your Tinaco & Roof Top PVC Pipes,
(especially when you have untreated well water).

One reader opined:
Put a pool puck in your tinaco.

Our thoughts on this:
Realize that the pool or spa tablets can work VERY WELL to release free chlorine, WITH RESERVATIONS – EXCEPTIONS – CAUTIONS:

~ Do NOT just put pool pucks straight into the tinaco – because they dissolve WAY TOO FAST releaseing way too much free chlorine too quickly … Notice how we put just 1 or 2 pool pucks into a SLOW RELEASE floater, to dissolve only very slowly, one puck treating a WHOLE swimming pool.

~ Next, notice that even using the floaters that heavily limit the amount of water flowing past the pool puck – the resulting swimming pool free chlorine concentrations ARE MUCH-MUCH HIGHER than you want continuously in your tinaco & plumbing.

~ The much higher swimming pool free chlorine concentrations from uncontrolled pool pucks damages the metal parts in our faucets, showers & plumbing… plus the extra high chlorine levels chew up the rubber seals in toilets, faucets etc.

~ Notice that pool puck are chemically quite simple … with solid chlorine salts that dissolve to release (disinfecting) free chlorine, along with Cyanuric Acid. The Cyanuric Acid is added to pool pucks to absorb the UV light from sunlight, that destroys free chlorine … (note that there is no Cyanuric Acid in swimming pool chlorine powders).

So … If you must use chlorine pucks … get the SMALL ONES designed for spas & tinacos … and USE A very small FLOATING chlorine dispenser, with only 1 quite-small slot open. 🙂

and finally … Don’t drink much of the pool puck water treated water – because the Cyanuric Acid is a little hard on our kidneys.


Dr. Steven M. Fry

Ph.D. in Chemistry, Environmental & Public Health, and Laboratory Measurement Science

Another local poster opined:
Just one note, if one has a water softener, one must not add chlorine nor pool pucks because those damage (shorten the life) of the softener’s resin (that’s what the guy said).

Notice that if your water softener guy was correct, then all of the water softners with resin, across America & Canda would be failing … due to all US & Canadian water districts chlorinating their water., with guaranteed residual-disinfecting levels of free chlorine in USA-Canada tap-water, as it exits or kitchen sink faucets. 😉

Then consider how (above) I wrote about the normal big pool pucks release way too much free chlorine for use inside a tinaco.

Unfortunately, the local “water softener guy” appears to not know about the special VERY SMALL floater-dispensers, that only hold the VERY SMALL spa-tinacao chloro tablets …

and he doesn’t seem to know about how you can adjust that VERY SMALL spa floating chloro dispenser, to have just one tiny slot open. 😉

And yes … He may have designed your system a bit poorly to not anticipate the algae plugging up the water softener’s resin … because well water is almost guaranteed to frequently introduce so much algae into the tinacks here …

Does he have really high quality sediment and algae filters and carbon filters installed before the water softener system – because a good set of filters, with a final GAC (Granular Activated Carbon) filter as the last step for polishing the water REMOVES ALL THE CHLORINE …

So, if your special water system was designed properly, there would be no free chlorine reaching your water softener resin …

= = = =

On to the NEXT issue of … Algae Crud Blocking-Plugging up Valves & Aerators in Mexican Homes:

What’s this??
(a local gringo asked)

It’s a blue green algae ..

Blue green algae spores are floating around all the time here in Yucatan, Tabasco, and Q. Roo.

Unless you maintain reasonable free chlorine levels in your tinaco & pipes … it will return.

If you have PVC tubes on the roof, exposed to the sun, the algae grows into quite hard chunks – and slowly clogs the pipes … and as time goes by, bits – chunks of that roof-top algae garden inside the pipe … break off … and plug up toilet fill valves, and plug up shower mix valves, and other things that can be difficult to clean or replace.

Once the algae is established (as proven by you finding it coming out your faucet), then just running water through the system does basically nothing to stop or clear it.

In our experience, you can hit the water system really hard with heavy chlorine …. and then let that strong chlorine sit in the pipes for an hour … and then apply a pressure washer to a low point in the system … to force gradually increasing pressurized water backwards through the system … opening a port in the plumbing on the roof, for all the accumulated algae to spurt out.

Then, after back-flushing/pressure-washing out the plumbing lines from different key points, then heavily re-chlorinate the system another time …. and then open the taps in bathrooms & kitchen, to flush out the remaining small bits of hard algae residues.

Basically … one has to treat well water about 1 time a week with a ½ cup of bleach per tinaco … to maintain enough chloro in the pipes, to stop new algae growth, as algae spores keep blowing in…

Welcome to Mexico.

Read On … MacDuff !

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