25 TDS, should I use it or no?

[mkengr45]

I recently setup a coralife RO unit and have a TDS reading of 25. Is this water too bad to use for water changes? I know ideally I want it to be 0, but is 25 really too high. I only ask because I know I will be puttin it in the tank which is full of fish poop, sand, mud, etc....... and I wonder if having a TDS of 25 is really going to be a major bad thing. My TDS from the tap is 324. The unit has only made about 100 gallons, and initially the TDS was 15 and it has now gone to about 25. What are your thoughts???



Randy

[dwdenny]

Does it have a DI to that at all. If not then you can add one and see if that helps reduce your TDS even lower. From what I have read 25 is a little high but not all that bad definatley better then the 324 tap. lol

[hobogato]

sounds like your unit doesnt have a DI section if the TDS from the beginning wasnt at or very near 0. my RO/DI had a TDS of 0 for almost six months, then it shot up to 258 when the filters wore out.

[matt]

Check to make sure you have a prefilter (spooled string or some sort of polymaterial) then a carbon block, then the RO membrane, then a D.I. cartridge. 25 TDS from a source of 300 sounds like your R.O. is working fine, but as the others have said, maybe no D.I. cartridge, or the D.I. cartidge is exhausted. Most R.O membrane have a rejection rate of about 90%, which is why you have 300 going in and 25 coming out. If you do have a D.I. cartridge, try disconnecting the line to it from your R.O. membrane and check the TDs at that point. It will probably be around 25, or should be. If it's a lot higher, something's wrong with your R.O. membrane. To be honest, I wouldn't worry much about putting 25 TDS in your tank, unless you have amazingly delicate animals.

If the TDS is 25 coming directly off the R.O. membrane and you want to go to zero, get a new D.I. cartridge, or if you have no D.I., you can get a separate D.I. canister. I've had great service from Bryan at purelyH20.com, and he's a MAAST sponsor. BTW, I would highly suggest you get a refillable D.I. cartridge and a bag of resin refill. I went through a cartridge in under 200 gallons. Getting a refillable will save you money in the long run.