Recent content by BuckeyeFS

You're not likely going to find a "max silica number" as the solubility varies with pH and temperature. If you've been using the same membranes for 5 years, it doesn't look like silica is an issue to be too concerned with, at least at your current recovery. Russ

Although silica can foul a membrane, it's not where I'd focus. A more common concern is hardness. Just as hardness forms scale on your plumbing fixures, it will scale the inside of a membrane. This is why we put softeners in front of many commercial RO units. Especially with well water...

Even quick connect fittings eventually leak - especially if the tubing is routes so there is lateral stress. The orings in the fittings need to be replaced periodically (think years).

Use a 5 micron, or better yet a 1 micron sediment filter. IF your carbon tank is working correctly, you won't need an additional carbon prefilter. Sanitize your system every other filter change or about once a year. Russ

As prefilters clog and rob pressure from the RO membrane, the membrane performance (how well it cleans the water, a.k.a. rejection rate) drops. In residential systems, the drop is severe at the lower end of the pressure range (e.g., less than 40 psi). Russ

The most common cause of off flavor/odor in RO water is a post-membrane "taste and odor" filter that is past its useful life and needs to be replaced. They are very inexpensive and easy to replace. If CO2 really is your issue, rather than boiling the water, you ca remove the CO2 @ less cost by...

Good point - as the meter error spec is expressed as a % of the reading.

But in practicality, the system user should occasionally be testing the feedwater as well to check the functioning (calculate rejection rate) of the membrane. So 342 could be reasonable. If they are only testing the permeate, as you said, something lower would be more appropriate, or as...

Hmm. That is a counterfit knockoff TDS meter, made to look like the TDS3 from HM Digital. I don't know anything about its quality. But assuming it is fine, you can use some calibration solution like this: You can get TDS calibration solutions at numerous TDS levels and the idea is to get...

Yep. We look at chlorine very differently than chloramine however. Membrane tolerance is only 1000 ppm-h.

I had to dig a little but found the reference I was thinking of re chloramine and residential membranes: The chloramine (excluding any free chlorine/ammonia) tolerance reported by Filmtec was 300,000 ppm-h.

Have you found a practical, cost effective means to warm RO feedwater? We've found the more practical approach is to add pressure to compensate.

We try to get people out of the knee jerk approach that when their permeate numbers or DI numbers are bad, they change the prefilters. Also - chloramine won't harm the membrane.

This process requires caustic as well as acid.

If you do some experimenting with your TDS meter, you'll find that the TDS after the prefilters is similar to the feedwater TDS. Nearly all the change in TDS in an RO system is accomplished by the RO element. Russ