100 gpd RO/DI unit with low water pressure

[kevensquint]

Hi, I have a 50 gpd coralife RO/DI unit that has that DI resin which dumps chloride back into the purified water. The effluent is always at around 10 TDS, and the sediment block,carbon and DI only last 2 months. I have found a new 5 stage unit also with TFC membrane, sediment block a different kind of DI resin and double carbon. Now what would the result be of using lower intake water pressure than suggested ( the water pressure in my apt. is kinda low) and I have heard that 100 gpd units don't clean the water as good as smaller units, what do you think?

 

[Randy Holmes-Farley]

The effluent is always at around 10 TDS, and the sediment block,carbon and DI only last 2 months. I

How do you know when the resin is depleted?

Now what would the result be of using lower intake water pressure than suggested

How low is your pressure?
Reduced pressure reduces the water production rate. It also leads to slightly less pure water penetrating the RO.

I have heard that 100 gpd units don't clean the water as good as smaller units, what do you think?

If you have a DI, the purity will be the same, but the DI might be depleted faster with some types of membranes, since they are not all the same.

This article has more:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria
http://reefkeeping.com/issues/2005-05/rhf/index.htm

 

[kevensquint]

My resin turns dark blue when it needs changed, so coralife says, to be safe I have been following that advice. My home water has 228 TDS, to give you an idea. I don't have a guage to mesure the water pressure, but I am assuming it is low since the outer sleeve on my last stage only fills up 3/4 full of water. I actually thought the opposit, that a pump to increase pressure would force more junk through the unit.

 

[dandydan]

My water pressure is low, My DI resin depleted in no time,
Now I have a pump the difference and speed is unbelievable, and the resin lasts more than twice as long.

Buy a Pump and dont forget a TDS meter, hand held or in line.

 

[Randy Holmes-Farley]

I actually thought the opposit, that a pump to increase pressure would force more junk through the unit.

Nope, not until the pressure is so high the membrane ruptures. But the effect is smaller than other effects.

My resin turns dark blue when it needs changed, so coralife says, to be safe I have been following that advice.

I wonder how that can work for an ion exchange resin as opposed to a true DI resin. I hope it isn't depending on specific ions being in the water.

 

[kevensquint]

I asked Coralife and they don't know either which explains why I'm buying another brand. Going with a good company that supports their products, thanks.

 

[Randy Holmes-Farley]

:lol:

Sounds like a good plan.