Greetings, I just recently purchased a HYDROLOGIC REVERSE OSMOSIS model 200 system. After hooking it up and letting it fill a 44gal barrel, I tested the water pH with an ECO TESTER PH 2 electronic tester. It measured at 8.7 (around 66F). I tested it again 30 minutes later after letting it fill another gallon or so and it tested 6.9. I re-calibrated the pH tester with the 7pH calibration liquid. I unplugged the line running from the system to the barrel and it tested 8.7 again. After waiting another hour and letting the line run into the sink, I tested again at 7. The Eco Tester PH 2 electronic tester is brand new and after recalibrating again I re-tested the water. I have been getting readings everywhere from 6.9-8.7 since then. Every time I test the calibration fluid it reads correctly at exactly 7, every time. This leads me to believe that the tester is working fine. (I've tested the water in my hyrdo tank at least 20 times in the past 2 months with this same tester and its always given me correct readings) Whats going on? Bad R/O unit? ...and yes I'm sure I'm not testing the run-off water from the unit because the run-off is 180 ppm while the water in the barrel is 10. Any ideas? Thanks, .:shalom:. ECO TESTER PH 2 HYRDOLOGIC REVERSE OSMOSIS 200
I know you might not like my answer if your certain your meter is correct your res container need to be flushed. The whole thing. Once a new filter is installed you must toss the first 6 gallons or so of water. By not tossing that water and having a dirty res and lines. I'd say flush the whole system. It's easy. It's gonna take half a day, but hey. There's crap in there. Gotta get it out gl
I don't suppose you calibrated at BOTH pH 4 and pH 7. Also - My RO directions said throw the 1st gal away when you change filters.
@ Tihspeed I did let it run into the sink for about an hour when i first installed the RO. That shouldnt matter anyways given that after it filled the 44 gal barrel, I unplugged the line and tested the water coming directly out of the RO system. The pH is still fluctuating coming directly out of the RO this morning. Depending when I test it its still varying almost 2 points. @Raoul I don't have the 4 pH calibration liquid, only the 7. And yes I did let the first number of gallons, an hour worth, drain out before filling the reservoir. My understanding is that RO water should be exactly 7 or damn close. Could I possible have a bad RO system? Thanks, .:shalom:.
ummm - you measuring the ppms as well? RO water will seldom be pH 7 .. really depends on the source water. If the RO has issues the ppm will bounce around. You might have something not quite tightly sealed.
I think maybe the weird readings are normal. RO water has no salt or minerals in it to register any electrical conductivity.So the meter has a harder time determining the PH. When I use my meter I clean the electrode and then let it soak in RO for a while. The PH starts high and then eventually settles in at around 6.4. If I test some solution with nutes in it it reads normally because it can do its job easier. Also I calibrate it at 4 and 7 so if Im in doubt I check it , if its good I trust it and mix up some dank nutes for the plants.
sorry, been out of town.. resolved???? I believe you have to let your ph pen sit in your water to be tested for 2 minutes depending on the brand of pen... so fill up a cup with ro... and let it sit.. see if it stabilizes...
That's it in a nutshell. Keep in mind that PH is a measure of the ratio between positive and negative ions in the solution (water in this case). If you have 100 neg ions, and 91 pos ions your PH will be a little acidic. If you have 10 neg ions and 1 pos ion your solution will be very acidic. Still a 9 ion difference but huge change in ratio. Since RO water is so clean and has so few ions, its PH can be changed drastically by small things. It's also probably much harder for your PH meter to get a read on it since there's not much there. Put some nutes (ions) in it and then test it. You'll probably be fine.
this is true... RO membranes can only push out devolved solids (TDS PPM EC), and damaged water molecules, and lets "good" ones through. a pH meter measures the concentration of hydrogen ions (H+). this is y RO water pH can be different from ur tap's pH. water is a universal solvent and tries to break down everything it comes into contact with, "pure" water (anything below 20 TDS) will pull things from the atmosphere, thus changing the ppm and pH. also water always tries to go back to its neutral state 7.0 pH. u can add a little cal-mag to ur water to create an equilibrium (aprox 25ppm after cal-mag is added) this will help stabilize ur pH and keep ur nutrients from falling out of solution. good luck with everything