Good RO water burning through DI???

[shogun97]

I'm hoping one of you guys can help me out. I'm burning through DI resin in less then a month. I have the dual refillable containers. I suspected my membrane was bad but after testing it today, its showing a tds output of 0-5.

Can you guys give me an idea of what else it could be?

Thanks,

[Rwinfrey]

I had the same problem high co2 was the issue the only way to remedy it is to let the water sit overnight with a bubbler. According to the spectrapure tech support guy

[shogun97]

So you had very low TDS from your membrane but still burnt through DI resin? Are you on well water? What is your Incoming TDS? I'm at about 98 - 115. How can I test or research if this is a problem in my local area? Thank you for the reply but I hope that is not the issue because I'm really not sure how I can have incoming water sit and then pump it through my RO/DI

Keep the responses coming guys!!

[acts4me]

How much water are you making?

[shogun97]

Not really an excessive amount. I'd say I make 25 gallons each week for water changes and about 3-4 gallons daily for my ATO

[on the spot]

Not really an excessive amount. I'd say I make 25 gallons each week for water changes and about 3-4 gallons daily for my ATO

Your make up water is made as needed or stored in a container? Constantly cycling the RO on and off could contribute to you problem. TDS creep. It doesn't seem to explain the whole thing though since you have such low TDS to begin with.

[shogun97]

I have a latching ATO system so TDS creep is not the problem. This one has really got me and I don't want to buy new filters if that is not the issue. The more and more I think about this perhaps the CO2 issue is what's happening.

If anyone else has any input please post!

[redfishblewfish]

It sounds like a CO2 issue. What is the pH of the incoming water? I'm willing to bet it is in the sixes. You either raise the pH or, as was suggested, bubble the water for a day or so.

[shogun97]

I think you may be right! I need to find a way to test low level ph because its out of the range of all my test kits. Any suggestions?

[bigdoug]

I had similar issues, one thing to make sure is when you pack your DI resin make sure it is solid to the squeeze. The first few times i had changed mine it only lasted a few weeks when the initial lasted 3months making 200g a month on average. Last change was a month ago and it hasn't started changing yet. My incoming tds is 470 out 0, on a 4 stage.

[redfishblewfish]

I think you may be right! I need to find a way to test low level ph because its out of the range of all my test kits. Any suggestions?


You can get a water treatment unit that raises pH….I think it is loaded with magnesium oxide, but don’t quote me. It’s expensive. If the pH is ok for other household uses without issue, what I’d suggest, for your fish tank only, is to run your RO unit into a 55 gallon drum (or some holding tank). Put an airstone with an air pump and let it bubble for a day or so.. Then use a small pump….some small maxijet or similar…and run this water through your DI unit. By allowing the water to aerate, the CO2 will get blown off and now won’t contaminate your DI resin. This is what I’d do….minimal cost.


If you have a means to measure pH, you will want to measure right after drawing the water and then after you bubble it for a day. You should see the pH go up as the CO2 gets blown off.