RODI media life span

[glenns]

I'm trying to decide if the cost savings of making my own water are worth investing in an RODI unit. But the two things I can't answer is how many gallons should I get from the membrane and other media? And how much water will be wasted? I have city water, not well water.

[slief]

That question is impossible to answer. A quality RODI with quality filters will get much better water volume of the cartridges than a cheap unit. An RODI with auto-flush will also help in cartridge longevity. RODI waste to DI water ratios range from 4:1 (waste to RODI) to 1:1 depending on the filter, number of stages, auto flush or not, booster pump or not, type of cartridges etc. If you spend more on a quality filter from a quality manufacturer, you will get better longevity and less waste. You spend less, the opposite can be expected.

Water pressure also has a big impact on longevity. Low water pressure results in faster cartridge depletion. Some filters come with booster pumps to insure constant consistent high pressure. Not only does tap water TDS impact longevity but so do the things your water company adds to the water and the amounts. Things like chlorine and chloramines for example. If you want to get a better idea, download your water quality report from your local water company and call a company like SpectraPure to get a real answer. Knowing your water pressure and your tap TDS, that will help get a realistic answer in conjunction with your water quality report.
Here is the water quality report for Ft. Worth.
http://fortworthtexas.gov/uploadedFi...h-2013Data.pdf

I use a SpectraPure UHE 90GPD unit that gives me 1 gallon of RODI to 1 gallon of waste. I get several hundred gallons of RODI water before having to change the first of two DI cartridges. The second cartridge lasts almost double that if not more. My tap TDS ranges from 475 to 500+.

This is an area that you get what you pay for. Also, cheap cartridges on a cheap fliter wont last long at all.

[ReefingWerewolf]

The guy I just bought my tank from says he hasnt changed his cartriges in 5 years, is that a serious problem. I will get new cartridges asap, but the first batch I make will use his old ones.

P.S. the ro/di does not include a tds meter, is that a necessity.

[slief]

Originally Posted by ReefingWerewolf

The guy I just bought my tank from says he hasnt changed his cartriges in 5 years, is that a serious problem. I will get new cartridges asap, but the first batch I make will use his old ones.

P.S. the ro/di does not include a tds meter, is that a necessity.

Yes, a TDS meter is essential in knowing the quality of the water you are producing. It's also essential in knowing when to replace certain cartridges. That is why quality TDS meters have an in and an out probe and why quality RODI's have two meters measuring multiple stages in the filter. 5 years and no TDS meters is pretty much a guarantee that your cartridges are worthless and the water you are producing is poor quality. That said, if your first batch of water is going to be made with the old cartridges, you will be doing so knowing that your water will most certainly be VERY poor quality. I wouldn't bother making water until you get some quality filters and some TDS meters to insure you can flush each cartridge properly one at a time before adding the down stream ones. Otherwise, you will likely kill or shorten the life of the DI's before you produce a gallon of usable water.

[ReefingWerewolf]

Originally Posted by slief

Yes, a TDS meter is essential in knowing the quality of the water you are producing. It's also essential in knowing when to replace certain cartridges. That is why quality TDS meters have an in and an out probe and why quality RODI's have two meters measuring multiple stages in the filter. 5 years and no TDS meters is pretty much a guarantee that your cartridges are worthless and the water you are producing is poor quality. That said, if your first batch of water is going to be made with the old cartridges, you will be doing so knowing that your water will most certainly be VERY poor quality. I wouldn't bother making water until you get some quality filters and some TDS meters to insure you can flush each cartridge properly one at a time before adding the down stream ones. Otherwise, you will likely kill or shorten the life of the DI's before you produce a gallon of usable water.

Even if I got new cartridges before I made my first batch, the system I purchased comes with liverock fish and corals, I will be keeping about half of the previous saltwater. Wouldnt the old water have the same problems?

[slief]

Originally Posted by ReefingWerewolf

Even if I got new cartridges before I made my first batch, the system I purchased comes with liverock fish and corals, I will be keeping about half of the previous saltwater. Wouldnt the old water have the same problems?

Could be but you don't know what's in your tap water and what nasties are built up in the filters that are just going to pass though. You have chlorine in your water, phosphates, copper etc.
http://www.seattle.gov/util/groups/p.../02_031815.pdf
If you like chasing algae issues and fatalities of your livestock, then you are going into this knowing the ramifications. I've given you advice. What you choose to do with that is your decision.

[ReefingWerewolf]

Originally Posted by slief

Could be but you don't know what's in your tap water and what nasties are built up in the filters that are just going to pass though. You probably have chlorine in your water, phosphates, copper etc. If you like chasing algae issues and fatalities of your livestock, then you are going into this knowing the ramifications. I've given you advice. What you choose to do with that is your decision.

Thank you very much, Im just a little freaked out because im keeping everything alive with heaters and pumps in trashcans in my basement, tank wont be ready for occupants for a few days, but now isnt a great time to hear that my entire system may be toxic... And that to know tds I probably need to buy whole new ro/di system. ughh

[slief]

Originally Posted by ReefingWerewolf

Thank you very much, Im just a little freaked out because im keeping everything alive with heaters and pumps in trashcans in my basement, tank wont be ready for occupants for a few days, but now isnt a great time to hear that my entire system may be toxic... And that to know tds I probably need to buy whole new ro/di system. ughh

You can buy TDS meters and add them by installing 1/4" push lock T fittings between the membranes. It's very simple and inexpensive. I'd contact SpectraPure and they can supply you with everything you need assuming you know what filter you have or can determine the cartridge size. Worse case, you could probably find salt water locally from a good fish store. You may be OK, but not knowing is a risk in and of itself and knowing the filters have not been changed for years is a major red flag. If nothing else, use what you have and start doing major water changes as soon as you get quality water but do so knowing that there is a good likelihood that problems will arise which will impact your short term success and may well result in casualties.

[ReefingWerewolf]

Thanks!

[ravi197699]

I had issue with DI resin getting exhausted very fast but I saw video from Bulk Reef Supply about same issue and they mentioned that if tap water contains more co2 then it will cause this issue so they suggested to run water though carbon before water reaches DI resin canister. So I added 2 more canisters that hold carbon before water reaches to my DI resin and I see that it is not changing color like before. I and output is 0 or 0.1 ppm from the output.