14ppm ro water. too high?

[Zeadon]

hi,

 

is that too high to use for reefing? if not, what order do i change the filers to work out which has gone bad. or is there another way to work out which has gone bad.

 

thanks.

 

zeadon

[amnestia]

14ppm is cleaner than most bottled water, if you aren't having problems with algae/cyano etc I would say you're fine

 

If you have an RO unit only then it's probably working alright, if you're using an RO/DI unit then change out the DI and it should bring it back to 0. Also check the prefilters, if they are yellowed then switch them out as well.

[cruiZe]

has it always been this high? do you have a way to flush your membrane? 14tds is alright, but could and should be better depending on the RO setup you have. I would blame the membrane before the prefilters at this point.

[Zeadon]

thanx for your reponses,

 

basically i just bought the unit off someone who has told me the filters have been in for a couple of weeks. its an RO/Di unit made by RO man, its got 4 stages in total.

 

this is going to be my first salt water set-up, so it hasn't affected me but i just wanted a go ahead from people before i used.

[cruiZe]

ooh, so its new to you, but used? i would run it for a while and see if the TDS drops any. Do you have any instructions or know how to flush the membrane?

[Dani3d]

It's the membrane and DI resine that is due for a change. I change mine when I get reading of higher than 7ppm.

 

Are you sure these were replaced recently? if so just let it run for a few hours before checking it again. If it is still at 14ppm after that, I am afraid that the person who sold it to you did not replace these filters.

 

 

hi,

 

is that too high to use for reefing? if not, what order do i change the filers to work out which has gone bad. or is there another way to work out which has gone bad.

 

thanks.

 

zeadon

[Zeadon]

again thanks for the responses,

 

it has a manual flush, i have flushed once or twice for like 20secs each time after which i got the reading of 14, how long should i flush it for and how long should i let water run through the membrane before retaking the reading? an hour? 3 hours?

 

zeadon

[Zeadon]

also id like to point out, my TDS meter is band new, it is the stick tds meter by D-D. it is exactly this one here:

 

http://www.warehouse-aquatics.co.uk/d-d-td...ter-p-4978.html

 

i bought mine from my local LFS.

 

should i be confident that it is giving me accurate readings? are these pre calibrated?

[cruiZe]

flush it for 10 min, let it run for 10 min then test it. If its not lower after that, i doubt its going to be.

 

i always flush mine before making tank water for at least a couple minutes. "TDS creep" happens when its sitting, even overnight. That is bad particles leech through the membrane some how then are built up on the good water side, so when you turn it on you get a blast of nasty that can burn through your DI stage (if you have one)

[Zeadon]

ok ive tried it, it is remaining at 14ppm. should i use it as is, or should i change the filters?

 

thanks

[amnestia]

i'd swap out the filters

[AZDesertRat]

Prefilters and carbons have very little to absolutely noting to do with final TDS, they are there to protect the RO membrane which does 90-98% of the work with the DI doing the rest.

 

To know how well the system is working you need three TDS readings, tap water TDS, RO only TDS and fianl or RO/DI TDS. Obviously 14 is way too high for an RO/DI but may be good for RO only depending on what your tap water TDS reading is.

 

At a minimum you need new DI resin but you need the orther two TDS readings to see how well the membrane is functioning, replacing DI only may be like using a crutch to prop up a poorly performing RO membrane so you need o troubleshoot the entire system. If the prefilter and carbon block(s) have not been changed in the last 6 months then it is time for them too and the systemn probably needs a good disinfection with bleach as the manufacturer recommends.

 

For future reference you change the DI resin when you first start seeing signs of anything other than 0 TDS on a consistent basis. You change the RO membrane when it is no longer producing 96-98% rejection rate or removal efficiency or when the cost of replacement DI resins exceeds the cost of a membrane in a short time.

You replace the prefilter and carbon at 6 month intervals regardless of usage or TDS readings and you disinfect the system at that time.