RODI/TDS question

[biecacka]

Yeah, my previous skimmer I ran for 2 years and never really got it dialed in. Switched skimmers and got the right sized skimmer and have to run it in lower water for now because the load isn't enough for the skimmer. I have also cut way back on feeding too tho so soon I'll be able to feed a bit more for the fish.
It's coming around with due diligence for sure.

Corey

 

[cvore2004]

Well, my .02, I definitely NEED Ro/Di for my tap water. My apartment reads 700ppm pre ro. My Di resin only lasts about 6, 10 gallon water changes.
Before I added the Ro/Di I was getting all kinds of unpleasantness in my tank. I know that my complex uses iron pipes for all the main lines, and copper for everything from there into the apartment itself.

For about the first year I was running about 30-50ppm on the old Di resin, and it was better, but after I found out that my Di resin was used up and switching it out my corals are much much happier, and I don't loose nearly so much cuc every week.

 

[jason2459]

Well, my .02, I definitely NEED Ro/Di for my tap water. My apartment reads 700ppm pre ro. My Di resin only lasts about 6, 10 gallon water changes.
Before I added the Ro/Di I was getting all kinds of unpleasantness in my tank. I know that my complex uses iron pipes for all the main lines, and copper for everything from there into the apartment itself.

For about the first year I was running about 30-50ppm on the old Di resin, and it was better, but after I found out that my Di resin was used up and switching it out my corals are much much happier, and I don't loose nearly so much cuc every week.

What kind of prefilter and membrane(s) do you have? How old are they? What pressure? I would look into getting the spectrapure 99% rejection rate membranes and make sure you have enough pressure. It will save you a lot of DI.

 

[bertoni]

Are you saying you only get 60 gallons per DI cartridge? That's very low. I agree it'd be interesting to know the TDS after the RO membrane. Maybe it's not seated properly, but the problem could be carbon dioxide, too.

 

[cvore2004]

I wasn't aware that pressure would affect tds. I thought it mainly affected longevity. I definitely need a booster pump, because my water pressure is at 20 currently at my apartment. The maintenance people keep promising to get it fixed by "next week".

 

[cvore2004]

Filter is a Kent maxxima with tms(?) membrane.

 

[jason2459]

Membranes are rated based on a certain temp and pressure.

I would suggest checking out spectrapure's sponsor subforum stickies. I would get the 99% rejection rate from spectrapure and give them a call as well to get the right flow restrictor. They are very helpful.

Edit: Just saw 20psi which is extremely low. Like well water low. Would talk to them about a booster pump as well. Need to get that up over 60psi. I keep mine at 80psi.

And like bertoni said CO2 would be a big factor but usually that's an issue with well water.

 

[bertoni]

20 lbs pressure is rather low, and the unit might work a lot better when that gets fixed. You could check the TDS before and after the membrane at some point to see what's happening. Hopefully, the reduction will be something like 98%.