New RO system raising ph

[gbf4ever]

Just picked up a 100 gpd ro system. Ran it for about 40 minutes first to clean it out like the instructions said, then filled up a 5 gallon bucket. Ph'd the water after and the filter raised it from the 7.3-7.5 range to 10. Is this normal? Do I just need to let it run awhile to clean it out?

gbf4ever Reviewed by gbf4ever on 06-08-2008. New RO system raising ph Just picked up a 100 gpd ro system. Ran it for about 40 minutes first to clean it out like the instructions said, then filled up a 5 gallon bucket. Ph'd the water after and the filter raised it from the 7.3-7.5 range to 10. Is this normal? Do I just need to let it run awhile to clean it out? Rating: 5

[Rusty Trichome]

RO likely isn't the problem. Mine lowered my ph from 8.0 to 7.9 when I first installed it.
What was originally in the bucket? Did you use ammonia to clean it, and leave some residue?
When I had my coral tank, I started using the buckets the aquarium salt came in. Altho well rinsed, they still had a 'cake' of white salt adhering to the sides of the white bucket, and it kicked-up the ph to around 8. (yes, I need new glasses) Had to use vinegar to remove the salts. Just fine, now.

Did you do more than one test? What method did you use to test...strips, liquid, or pen? If you use a pen, do you have a calibration solution?
Might want to check an outdoors spiggot (or one not on the RO system) and do a side-by-side test.
Hope ya get it figured out...not sure I'd want to drink water at a 10 ph, let alone trying to adjust it for the ladies every day.

[gbf4ever]

Calibrated my ph meter before the test. Inlet water was 7.5 outlet water is at 10 still. Collecting it in the 5 gallon buckets I usually use for my water. Collected some in a plastic party cup just to make sure and still came out at 10.

[gbf4ever]

Just checked it again, let it run overnight and the ph is in the 6.4ish range now, so must of just needed a good flush.

[gbf4ever]

This morning I had to go get an adapter for a different faucet so unhooked it while I ran to lowes. Took the pH just as I started it up and it was coming out 6.4. Used it to fill a 5 gallon bucket and the ph is back up to 9. Figured it may be the bucket so filler another small plastic cup(same way I checked it when I started it up), and the pH of the water coming out was 10.0. Seems like the longer I run it the higher the pH gets. Any ideas what might be causing this? Going to contact the manufacturer and the store I bought it from to try and get a replacement.

System is a Hydrologic StealthR0100

[Rusty Trichome]

Sounds to me like possible meter problems. Is it a Hannah?
Before taking apart your RO, I'd go get one of those freshwater aquarium ph test kits. $6.00 or so. Check it against your meter and see if there is a difference. Doubtful there would be anything in the RO system that could possibly raise ph.

[gbf4ever]

Have one of the liquid test kits. Tested my tap water with it and it came out in the 7.3-7.5 range, my meter said 7.4. Reads 7.0 in the 7 calibration solution, and 4.0 in the 4 calibration solution. My liquid test turns aqua with anything over 7.5 and thats what the RO water came out as.

[gbf4ever]

The meter is a Milwaukee btw, not a Hannah.

[gbf4ever]

Think you might actually be right rusty. Just went and checked the bucket I have filling now with the liquid test and it came out between 6-6.5. Checked it with my meter and was reading 8 something.

Any idea why the meter would be dead on in the calibration solution and be so off reading the water? Going to go ahead and order a new one, need a tds meter anyways.

[stinkyattic]

It's probably a meter designed for high ionic strength solutions.
RO water is by definition a very LOW ionic strength, and it takes a more sensitive meter to read it perfectly. Your buffers, on the other hand, would be a very HIGH ionic strength solution, and your meter can 'see' the number more clearly, like a book with bold print.

If I were you, I would not concern myself very much with the initial pH of the water from your system. Check the ppm coming out instead, to make sure that the system is working, and then add your calmag and nutes, and THEN check the pH. By adding fertilizer, you raise the ionic strength to the level that your meter, which is a good one btw, was designed to read accurately.

Hope that helps.