RO vs. Tap Water Filter for nano tanks

~Rookie Wookie~ · 09-16-2003, 11:34 AM

What would be more cost efficient in the long run for a 10g tank? Given the fact the RO unit will waste water and the filter will not. In most cases, the tap water filter will make anywhere between 50 and 150 gallons of DI water.

What is the avg price for one of these water filters from Aquarium Pharmaceuticals? I do a weekly water change of about 20%, what do you guys think is a better choice?

Jeremy1973 · 09-16-2003, 11:46 AM

Is there a store near by that sells RO/DI? As soon as your tank matures, you will not need to do weekly water changes. It got to the point for me, I only needed to do a water change once a month and everything was happy and flourishing. (Even had a leather coral spawn). So, if there is a store that sells it, that is an option, or if there are any friends with a unit..I would talk to them about chipping in some pennies for getting water from them.

~Rookie Wookie~ · 09-16-2003, 11:58 AM

Hmm gonna have to look around, I live in the SF Bay Area and have just started to explore this hobby.

My tank is about 2 months old right now and I think what you're suggesting may actually be even more cost effective than what I had in mind in my initial post.

mnreefgeek · 09-16-2003, 12:58 PM

Just be careful where you buy your water from. I buy all of mine at a LFS right now. I was going to get it from one of the local markets with the machine outside, but you have to trust that their filters get changed when they need it and not on some schedule. I almost guarentee that if you took a TDS to most of the water coming from these machines, you'd start looking for a different source.

HTH

ckreef · 09-16-2003, 06:54 PM

Quote:

Originally posted by mnreefgeek
Just be careful where you buy your water from. I buy all of mine at a LFS right now. I was going to get it from one of the local markets with the machine outside, but you have to trust that their filters get changed when they need it and not on some schedule. I almost guarentee that if you took a TDS to most of the water coming from these machines, you'd start looking for a different source.

HTH

The problem you describe is the same problem you get when buying from a LFS. I bet most LFS's do not change their DI catridges as often as needed considering the amount of water they make. In Atlanta area we tested many LFS water samples and not one was up to par in my book --- neither was any machines and even some bottled water from a large Grocery store tested at 45 ppm.

The only water you can trust is the water you test w/ a TDS meter ---- PERIOD

triggerhappy8 · 09-16-2003, 07:07 PM

ckreef,

What do you consider not up to par for RO water? If you could, pm me the places that were good. I recently tested the RO water from the Publix on North Ave downtown and it tested 2.5. Is this good or just ok?

Thanks,
Craig

ckreef · 09-16-2003, 08:00 PM

2.5 is good --- I consider anything 10 ppm or less as good.

It was Publix water that came out at 45 PPM --- It was a sample that was brought to one of our club meetings by a member that I tested. I do not know what exact store it came from other than the Northwest corner of Atlanta outside the perimiter (thats approx where he lives).

I know how quickly my DI cartridges get used up (tested w/ a TDS meter). At even close to that rate a LFS would have to change out it's DI cartridges every week considering how much water most of them go through.

Have you seen my post about the Nano SIG meeting in the Atlanta area. Everyone is welcome and we usually arrange for everyone to take home a few frags for $5-$10. These Nano SIG meetings are a blast --- hopefully you can make the meeting even though it is on the far South side of Atlanta

triggerhappy8 · 09-16-2003, 09:40 PM

ckreef,

That Publix water is a quarter a gallon. Is that reasonable? It is only RO water so there is no DI filter to be used up. It is however checked and cleaned every week (or at least has a sticker that says it was cleaned on such and such a date). Yes I know about the nano SIG meeting and plan on going. I have to return 9fishers TDS meter that I used to test that water. Getting a few cheap frags sounds awesome. I only have one ricordea and am getting some frogspawn, zoos, and candy cane next week. See you at the meeting.

Craig

ckreef · 09-16-2003, 10:21 PM

Craig ---

Can't beat a quarter a gallon.

Glad your comming to the meeting --- see you there.

Ray1214 · 09-17-2003, 07:10 AM

They are awesome meetings, I can't go to this one.

Charles,

How often are you having to change out your DI filter? My unit is going up to 31 PPM from 5. I reverse flushed the membrane to bring it back down a bit but the unit is about 6 weeks old. I have a new di filter but do the die away that fast?

Ray

Ray1214 · 09-17-2003, 07:11 AM

Oh yeah, I have probably made about 160 gallons per water, not counting overflow.

Ray

Jeremy1973 · 09-17-2003, 04:01 PM

Mine tests at 0 ppm!

ckreef · 09-17-2003, 04:34 PM

How fast the DI goes is really determined by what is in the water and what comes out of the membrane.

Something doesn't seem right on your system --- Unless you have really bad tap water --- then the membrane w/out a DI filter should be less than 31 ppm.

Test your tap water. (most around Atlanta is well under 100 ppm)
Test water after membrane (before DI) --- this should be at least 80% less than your tap water and more like 90% less

example tap = 100 ppm
membrane water should be no more than 20 ppm but propbably around 10 ppm

After DI it should be 0 ppm but will slowly rise until it meets the membrane water (10 ppm in our example) --- at that point the DI is doing nothing --- If you never chage out your DI at some point it will start to leach stuff back into the output causing it to be even worse water.

The only acurate way to determine if your cartridges are used up or not is by testing with a TDS meter even the color changing ones are not accurate and should only be uised as a general status.

Do a little more checking and let us know -- Also your flow restrictor has alot to do with what your output is and how effient your membrane works. Remember in your generic system a generic flow restrictor is used and might not be restricting properly for your particular situation. For a few dollars you can buy an adjustable flow restrictor (micro sized gate valve). I strongly recommend everyone get one of these and fine tune your output water V. waste water ratio for optimum performance.

I do have a large writeup I did on all this and at some point will get it uploadeed to the ARC website for everyones use --- but then again my task list is long and thats close to the bottom.

Let us know what all your different stages of water test out to be --- also take a 20oz glass and time how long it takes to fill up with product water and then how long it takes to fill up with waste water --- that will tell us if your restrictor is working correctly or if there is something wrong.