When to change RO/Di filters?

[catmel]

I have melev's reef 100gph Ro/DI.

I was curious as to when I needed to replace especially the DI filter part. On his website he says 6 months to a year but also mentions color change and it may vary due to the lack of or the amount of impurities in the water. So far I've made about 50-60 gallons total and I'm seeing a color change ( see below) - is this normal? Or will I have to change the filters sooner?

I read a TDS meter is the best way to tell, but was curious about the color change. Add TDS meter to the to buy list!

 

[Tank2379]

How long have you had your RO Unit for?

 

[catmel]

I've had it since christmas. I only started using it in late Jan / the beginning of Feb due to below freezing temps.

 

[melosu58]

I just change my filters every 6 months. The membrane every two yrs and the DI part every yr. Yes a TDS meter would tell you.

 

[catmel]

Ok Thanks I'll keep an eye on it and just plan to change in a few more months.

 

[CaptainAhab]

TDS meters are cheap and a great investment. $15-$20

 

[catmel]

Ill look into getting one. Thanks!