To flush LECA medium with tap water or reverse osmosis water?
 

I have all of my orchids in self watering pots and the majority I use LECA as medium. I water using fertilized reverse osmosis water. I also flush all the LECA pots with tap water once a month. I recently ordered a PH and TDS meter since I'm focusing on trying to learn more about how to properly feed my orchids. Of course I wanted to check out my new equipment and started out by testing my tap water. I am on a public well so I didn't expect perfect water. I was a little shocked to see that the TDS meter read 647. I'm still trying to understand what this meter even tells me. I think it's basically telling me how many impurities are in the water? Should I continue to use tap water to flush my pots or is it ultimately going to be more damaging than helpful? Please help!

Could you get a water analysis report from the utility managing the well?

Possibly, they don't exactly keep great busines practices so I'm not hopeful that they can or will even want to provide me with that information. I can try on Monday, hopefully they will actually be there lol

The TDS meter is measuring how much electricity the water conducts. Pure water is a poor conductor of electricity, but once certain things dissolve in it, it starts to conduct electricity. The TDS meter measures this effect and is only a rough approximation of PPM (parts per million of dissolved solids).

So, that TDS reading is only a very rough estimate of how pure and clean your water is. The issue is, if you don't know what's in there causing those high numbers, the water is suspect.

Also, is there a water softener in use? Many of those use salts that can be highly detrimental to the plants.

Even if you have really good tap water, if you have access to RO, I'd say that's ideal for flushing. You could also flush your pots with tap, then follow up with RO (to conserve the RO and still get some of the benefit), but again, it's better if you actually know what's in the water.

Thank you, I appreciate the information. I guess I'll be going to refill some jugs then, because it's flushing day lol. I will also try and see what I can find out about my water. I am very curious to know since I use it for my dogs and my cats love to drink straight from the tap.

Considering your geographic location, you water is likely quite hard and alkaline. I'd definitely use the RO water exclusively.

If they are providing drinking water to you, they are required by law to test it, and are also required by law to make that information (test results) available to you. You have rights here, and as operators of a public water supply, they should know this already.

Oh yes, even if they seemed to be able to provide the information, I still wouldn't trust it. I only use it for cooking and my animals (lots of dogs around here, must be good enough for them lol). I've only lived in this little place for two years, my dad has been here for about 17 years. In all of that time there has always been drama surrounding the water company. And the ppl who run it always seem to find a shady way around things. There is a group on Facebook dedicated to trying to improve how things are run that was started when we first moved. They seemed to give up after a year. They did get new people in to run it for a very short time but after a few months the old guys were right back in their old seats. Unfortunately this is an easier said than done situation, and it would be easier to relocate than to try to make another change lol.

---------- Post added at 08:38 AM ---------- Previous post was at 08:19 AM ----------

It's definitely hard water! You should see the salt build up on the clay pots I keep my cacti in lol. It's not the hardness you can boil out either... I've tried.

You cannot boil out any hardness. You may boil away the water, but the dissolved minerals are there to stay!

Not exactly.
There are 2 well-known types of hardness, "temporary" and "permanent", based on whether boiling can cause some of the hardness to precipitate as scale (such as in a boiler, or even in a tea kettle). For an explanation, see:

Permanent hardness in water @ Chemistry Dictionary & Glossary

Boiling will not efficiently reduce hardness, but could cause some reduction in the temporary hardness.

Different subject, responding to the OP, complain to the state agency that oversees drinking water systems if the public utility that serves you is not doing their job.