question about my ro/di filter

[mwoodruff964]

Ok my setup is one from the filter guys and its a OCEAN REEF + 1 FIVE STAGE 75 GPD RO/DI, I have also added a dual membrane to help cut down on waste water. my pressure gauge reads 64psi its less than a month old and on the tds meter its showing 7 tds but the di resin has not changed any color. My tds reading before the di is reading 7 as well, is it possible that my di resin is exhaust without starting to change to any color or is my calibration off in my tds meter?

[jtma508]

That's odd. First, you really need your pressure up around 80psi for the membranes to work correctly. What is the incoming water TDS? Are you sure you plumbed the unit correctly? I have a FG ReefMiser 150gpd 6 stage unit and love it. But it is really easy to mix-up the plumbing if you're not careful. Have you back-flushed the membranes?

[shifty51008]

64 psi is ok, is that psi going into the 1st or the 2nd membrane? you need at least 60psi going into the 2nd membrane also in order for the 2nd one to work correctly and most people need a booster pump to get that much.

[reo]

Sounds like either your TDS meter's calibration is off, or maybe it's measuring something other than the DI output?

[mwoodruff964]

i believe its 64psi coming through the first and it worked like a top until recently and I havn't changed anything. what else would it measure other than the di output if the outgoing tds is right after the di filter? I always backflush after each use for about a minute or so.

[mwoodruff964]

How would I recalibrate the tds meter

[mwoodruff964]

I wouldn't know what my incoming is because the "in" sensor is after the ro membrane and "out" is after the di, i figured i really didn't care what my incoming water tds was as long as the final product was 0

[disc1]

If the stuff coming out of the DI chamber has the same TDS as the stuff going into it then something is wrong with the DI resin. It is either exhausted, or has built up channels so that the water is really only contacting a small portion of the resin and the rest is just sitting still. Also, are you sure that this is a color changing resin? I'm not familiar with the RODI unit you have, but I do know that not all DI resins change color.

[mwoodruff964]

it said that it came with color changing di resin with the unit, i have noticed that sediment filter has became a orange yellow color would that have anything to do with it

[mwoodruff964]

i know this might be a dumb question but having a 7tds usuable in the aquarium

[Tigé21v]

I know it's a pain, but have you tested you meters by switching their places? If the one after the DI is out of whack and reading high, it should read more than 7 if you put it before the DI.
7 tds water is not as good as 0 tds water, but it's better than tap water. Seems its usually some sort of phosphates that are in that 7 tds, you'd just have to remove it from the water column in some other manner (GFO)

[disc1]

It depends on what the 7 TDS are. If it is chlorine it's bad. If it's sodium chloride it's no problem. If it's phosphate it will grow algae. If it's copper it will kill inverts. TDS just tells you something is in there, but it doesn't tell you what.

[Buckeye Hydro]

mwoodruff - there is some good advice above.

The first thing I'd recommend you check is the alignment of the "out" probe. Check your instructions - the probes have to be aligned correctly. Give us a call if you have questions or don't have the instructions for the meter.

Russ