DI water filter question.

[Evolutionz]

Hey guys, i just bought a 2nd hand Crystal Pro 3 stage water filter and previous owner told me he use the filter for a few months only and left it untouched but with water inside, this crystal pro comes with a TDS meter hooked on it and when i tried tested it just now. the TDS meter measured my inlet water (water that haven't been through the filter) at 65 - 70 PPM. and the outlet water after passing the filters, ranges from 10 - 20ppm. I know DI should be 0ppm... is there a need for me to replace the Resin inside the filter?

[ryanlio]

Some resin change colors to indicate that it has exhausted.. u might want to try to reduce the flow as well.. and, u picked it up before i do.. haha..

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[Evolutionz]

Thanks for your reply and sorry for beating you to it haha... Dark color means resin exhausted? the flowrate i put it to the slowest already.. slowest ppm reading is 10 - 15.. faster flow and ppm go up to around 20.

[ryanlio]

For me.. the new resins is orange brown.. when exhausted it turns black green.. as indication.. anyways.. madpetz do sell refills..

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[tqut]

Best to slow the water flow and let the water run for a while before taking the reading to determine if the DI is really exhausted. As you mentioned, when you slow the water, the TDS reading drops, so the resin may not be exhausted yet. Best to use the TDS meter reading and not the colour to determine the status of the resin.

My RO/DI last changed resin and filters 1.5yrs ago and I collect about 20L of water a week.

Hope this helps...

[Evolutionz]

Thanks for ur advice.. Today I filled up my tank 34L with the water filter at a TDS output of around 10.. I guess it's usable since my tap water tds is 70.. Resin color I can see 1/4 - 1/2 amount is darker color and the rest are orange..

[Evolutionz]

woah, yesterday took a photo with flash and it seems like most of the resin inside is dark... no wonder im getting 10 - 15ppm.

should i change?

[JeffL]

hmm i think this is the colour when the resin gets into contact with water...

my resin when deplete does not change colour, cant tell by colour

[tqut]

hmm i think this is the colour when the resin gets into contact with water...

my resin when deplete does not change colour, cant tell by colour

The resin will only change colour if it is colour changing type. I think Madpetz stopped selling those. I bought mine from them when they had the resin sale about 1.5yrs ago.

[Evolutionz]

Thanks for ur advice.. Any idea if its ok to use 10TDS water? it just meant that its not as pure as 0tds right?

[stevenchia]

Yes i do use 10 to 15.. once reach 10, it will be shooting fast up to 20 and over. Recommend to change after 10, since it will be shooting up fast. Some ppl like to maintain at zero. up to own indivdual.

And remember your carbon need to be replace too.

[Evolutionz]

Thanks for ur reply.. Since the crystal pro comes with one carbon and 2 resin should I stick to it? Or change to one sediment one carbon and one resin? Thanks!

[vtecintegra]

Can't tell from the picture, but is there not an RO membrane across the top like in the pic? If there is no RO membrane, you may never get 0 TDS. Other than that, I'd change all three filters in the unit. Look very dirty.

[Evolutionz]

i dun think thers any RO membrane inside.. i didnt know i needed that.. read many DI set up and all uses carbon and DI resin only..

Anyway, today i went to test my DI water freshly mixed with red sea coral pro salt and my API nitrate test kit shows that my DI water nitrate is 0ppm.. didnt have any po4 test kit though.

[vtecintegra]

I'd probably do a 5 micron filter, then carbon, then DI and add a RO membrane. With that you should get zero TDS for a long time. I get no PO4 with a similart setup using reef crystals salt.

[Evolutionz]

thanks for ur advice, will look into that.

[tofubox]

Bringing up an old topic. I was wondering when i should change my DI resins. Considering i am only keeping SPS at the moment. Currently using the crystal pro DI 3 stage, with madpetz resin. Reading is now 3 up from 0 after 2 mths. Is it still considered ok to use for sps dominated tank? Or am i always looking for 0ppm. Changing the resins isn't the issue, but i would like to know what is the limit? Change at 5?

[Evolutionz]

depends on your own, some change at the slightest rising of tds, as they want it strictly at 0, to me singapore water is fine, i change my resin when tds exceeds 10. i actually even top up some water with just tap water + seachem prime.

[moonwater]

I think it's our own preference, since TDS meter only measure ppm, it can be 5ppm of nitrate which is bad, or 5ppm of calcium...

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