Waste Water to DI Water Ratio

[ECFENCING]

Has anyone ever measured their waste water to DI water ratio?

Just ordered a new membrane and I am at 2:1 (75 gpd Dow RO Membrane with a capillary flow restrictor rated for this membrane). The original membrane from Bulk Reef Supply was supplied with a restrictor rated for a 50gpd unit instead of a 75 gpd unit.

I realize that this will change with colder water temps (ratio should go up) but if I continue to run at 2:1 won't this lead to premature failure of the RO Membrane?

What can I do to increase the ratio to 4:1? My understanding is that this is the ideal ratio since you need this ratio to carry away the impurities from the membrane. Running it at too low a ratio will lead to clogging and premature failure.

My water is relatively hard about 6 grains and TDS is above 300 depending on the season. I think you can get away with a 2:1 ratio if you have soft water

 

[noelskii]

I have a 75 GPD 5 stage also. My ratio is 4:1 using the faucet adapter with cool/warm water. My TDS is not 300 though, it's around 50+.

 

[ECFENCING]

thanks noelskii I think I am going to change the flow restrictor to a 100gpd unit and restrict it more. I'm getting closer to a 3:1 ratio now that I let it run a while but not the ideal 4:1 yet

Don't know what could be causing it though.

 

[pecan2phat]

Hi Ernie,
Curious as to why an old relic like me has been trying to achieve (as close to as possible) a 2:1 ratio vs your wanted 4:1 ratio output.
Don't get me wrong, you probably know and do a lot more research then I do but I try everything from higher PSI to piggy back membrane just to waste less water, what am I not understanding here?