Question about RO/DI. Advice needed

[dunkuboyz]

Hi all,

Need some help... I'm currently using an RO/DI from madpetz rated at 400gpd which comes with 2x200gpd membranes. I've been using this filter since the past 8 months. Plus minus, I use about 600G per month.

Over the past 2-3 weeks, I have been noticing diatom blooms despite PO4 and Nitrates at desired levels. It could possibly be overfeeding too....

But, was wondering, how long does an RO/DI membrane last? When do I know when to change it? Or should I change it on a yearly basis?

What about the DI resins? Do we need to top it up or replace it at regular intervals?

I guess, I have been neglecting the filtration part of my system.

Please advice and help...

On another note, can anyone help suggest where to get affordable replacement prefilters, membranes and resins so I can do more regular changes.

Many thanks in advanced

[tofubox]

Hi bro, sounds like ur resins and membrane is exhausted already after 8 months. Best way to check is to get a TDS meter. I am using madpetz resin, cheap and good.

[dunkuboyz]

Understanding how RO membranes work, unlike per filters, they do not exhaust.... Rather, they get damaged. Basically, at the RO membrane, filtration due to osmotic pressure rather then the hydrostatic pressure comes into play in contrast to hydrostatic pressures at the prefilters resulting it in requiring frequent changing and getting exhausted. In a nutshell, Impurities get trapped in prefilters, but not in membranes.... It's not suppose to.... At the membrane stage, pure water seeps through the membrane via osmotic pressure leaving behind water with highe concentration of dissolved impurities which gets wasted. Now, my question is... How will I know if it is damaged? From what I read, TDS is not an indicator for a membrane change.... As for the resins, do you add or do you replace and throw away the remaining in the cartridge? Many thanks

[tofubox]

Lol, you going pretty deep. I usually just change out my resins when i get tds more than 5. Probably others can give input.