# R.O. Unit Still Good After 5 Years?



## Fishthusiast (Jul 18, 2013)

Hi!

This is my first post here, or at least I think it is, since I may have been a member to this forum many years ago. Anywho, I am dabbling with the hobby again and going through a lot of my old equipment. I am a fairy experienced hobbyist with fresh water, although I have a long ways to go to be where I'd like to be with it. If this post is in the wrong section, feel free to move it.

Right now, I have a little 10 gallon with some driftwood and black sand set up. The reason for this post in particular is that I have an R.O. Unit--a 50 GPD Coralife Pure-Flo II, 4 stage--and I am wondering if it is possible that it still works as it should. 

Some details: 
-it had not been used in 5 years and none of the parts have been replaced. However, it was not used all that much in the first place
-it is in a basement, which is a generally cool environment (however, the membrane was not refrigerated)
-most importantly, I have been testing the pH of the R.water consistently with a brand new pH test kit, and it has been generally reading a 6.0 (in the yellow on the test card) which I am assuming it is where it should be if the unit is still working.

Of course common sense would say that there is no way it would still work after all this time, especially after no parts have been replaced. I am also wondering which parts would be most likely to have failed after this time. I am assuming it would have been the membrane.

Let me know what you think. I am more than willing to volunteer more info.

Thanks for the help!


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## niko (Jan 28, 2004)

Mine is 10 years old. TDS was 2-8 now it is 30-50. I used to make 200 gallons of RO a week with that unit some time ago. Thing is rusty and ugly, the plastic hoses break from old age. Still good water.


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## Fishthusiast (Jul 18, 2013)

niko said:


> Mine is 10 years old. TDS was 2-8 now it is 30-50. I used to make 200 gallons of RO a week with that unit some time ago. Thing is rusty and ugly, the plastic hoses break from old age. Still good water.


Thanks for the response. Hmmm. It's just that I didn't use it for 5 years and I did nothing to preserve the membrane. On top of that, there was one reading that seemed weird... I left some RO water out for a few days in a plastic container and then checked the pH, where it read a 6.6. However, every other time I have tested it, it has tested nothing (6.0).

I wonder if there is any way to test the unit besides just the pH and hardness to see if it is working properly...

Oh, and what is TDS?


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## Yo-han (Oct 15, 2010)

Fishthusiast said:


> I wonder if there is any way to test the unit besides just the pH and hardness to see if it is working properly...





Fishthusiast said:


> Oh, and what is TDS?


You answer your own question there! TDS is the real way to test whether your unit works properly. It stands for Total Dissolved Solids. You can find very cheap meters for less than 30 bucks that do give you at least a rough idea. Or take some water to your lfs. They probably use one over there.


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## Fishthusiast (Jul 18, 2013)

Yo-han said:


> You answer your own question there! TDS is the real way to test whether your unit works properly. It stands for Total Dissolved Solids. You can find very cheap meters for less than 30 bucks that do give you at least a rough idea. Or take some water to your lfs. They probably use one over there.


Yeah, I have a Kh and Gh test kit. However, if I am getting some pH, then there has to be a little KH, which is why I usually only test for the hardness if I am getting a pH reading.

This is a slightly different topic, but instead of starting a new thread I guess I can just post it here.

Does anyone have issues with their substrate as buffering their water? With my situation, I mix RO and tap to soften, usually about 3 gallons RO and two gallons tap. However, I am noticing that the sand I am using is potentially buffering my water. I am testing this by putting a handful of the sand in a plastic container with some RO water (and the RO water by itself is testing as having no hardness or pH). With the sand added, I am now getting a pH of a 6.5, so the sand is buffering somewhat.

So, if I am doing water changes with water that has a pH of 7 and a Kh of around 1, and the sand is buffering the water in addition to that, the pH of the water will go above a 7, correct? That is basically what I am experiencing: putting the water in the tank at a certain pH and having it raise after the water has been in there for a few days with the sand.

There are no fish in the tank yet either. Only the water and sand.


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## Yo-han (Oct 15, 2010)

No pH is impossible, every liquid has a pH. If your RO water was absolutely perfect (TDS=0) than the pH should be 7. If it is above or below 7 there are still some acids or alkalies in the water. But it tells you almost nothing. The same zero TDS water and breathing in it ones with a straw and the pH drops below 6. Same water, nothing added except CO2 which will be gone the next day and pH will be 7 again. So my point is, measuring pH is absolutely useless in RO water!

About the KH... KH is the main reason why we use RO units, so if this is your main reason to use it, measuring KH is ok. Remember that most aquarium grade testkits are not that precise and may be off. So a result of 1 may be 0 or 2 as well. That is why you need to measure TDS. It measures everything in the water at ones. The lower the better! When it gets above 20 I would replace the membranes.

Usually when a membrane is not used for 5 years it will probably be dry. If it is, it is probably garbage. If it was still wet, you can flush it and test TDS and see whether it is still good.

About the sand. Pure sand is SiO2 and would not add anything to the water. But most sand does contain some lime in it so it raises KH a little. Probably not enough to worry about.


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## Fishthusiast (Jul 18, 2013)

Johan, I appreciate the feedback. I will respond to your post, but I just don't have the time at this very moment. Please check back in the next day or two if you can. Thanks!


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## Fishthusiast (Jul 18, 2013)

Ok, I'm back, and I have WAY more questions than I have answers. I am just going to post here. If things are too 'off topic' then I guess the moderators will move things around.

Here are my goals: to have a little 10 gallon tank with tetras, my driftwood and possibly some live plants. In other words, a soft water, amazon-esque tank, which is basically what everyone else is doing on this forum. I bought the RO unit because my tap tops out with a pH around an 8 and 40ppm nitrates. This was unacceptable to me, so cutting the tap water with RO made perfect sense. From what I know, the lower the Kh, the lower the pH. I am shooting for a pH around a 6.8-7 range. So, I usually make about 4 gallons of RO and mix it with a 1 gallon R.O (roughly) and, after aeration, the pH ends up around a 6.8. It leaves me with about 1 degree of Kh and 2 degree Gh. I figured these were pretty optimal soft water conditions. So, am I doing anything wrong?

I do not know how to measure TDS. I have only ever tested the Kh and Gh. I will first test the Kh and Gh of the tap water (which is almost always consistent, obviously) and then I will test again after I have mixed the tap and RO. Usually I get this down to a science: Make the RO, mix it with tap, aerate, test, get it to temperature, add to tank by dripping it in.

The sand is DEFINITELY adding Kh, albeit slowly. See, my concern is that I am doing the RO/tap mix and getting it just where I want, but then when I add the 6.8 water to the tank it is then buffered even more by the Kh the sand is adding. Yes, Yohan, you are right that the sand isn't adding THAT much--probably 1 degree of KH--but it is adding it regardless, and I _think_ that this is why my pH is rising after I add it to the tank with the sand. Instead of me having just the 1 degree Kh with the water, I am getting 2 degrees Kh with the sand AND water combined, pushing my pH to a 7.2.

And another issue... I have something that is growing on my driftwood. In the past, I had brush algae that came in on the plants I put in my tank. The tank eventually came down and the driftwood went dry for years. After I soaked the driftwood again, I noticed a 'white fuzz' growing on it. I then boiled all the driftwood and the white fuzz has returned. I can only assume this is still the brush algae, but I am simply AMAZED that it could come back like this. Question is, if the boiling did not work, would bleach? Is it even safe to bleach driftwood? I was considering spraying bleach and THEN boiling the wood. Thoughts?


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## Fishthusiast (Jul 18, 2013)

Thread Bump! An thoughts?


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## WallaceGrover (Jul 28, 2012)

You could try to use peat to lower the pH, but I suppose that wouldn't help you with the kH and GH problems. My tap water is something like 8+ pH right out of the tap with kH in the teens, so I can definitely understand your problem. I wouldn't be so sure it was the sand causing a kH rise.

On the algae, no amount of sterilization is going to keep it down if the conditions are conductive to growing it. Even if you could sterilize the wood perfectly the algae could come in via any plant, or even through the air on spores. Maybe your light is too high or you have nitrogen or phosphate that plants aren't competing with the algae for...


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## MissileBear (Feb 28, 2013)

Pure water should have a pH of 7 with no KH or GH. You would be hard pressed to get this without using DI resin; for our purposes it really isn't needed as we need some KH and GH. Your RO unit should be fine for what you need to do even at it's current age. Membranes for that unit are cheap; assuming that you don't have a lot of hard water buildup inside the unit, replacing the membrane & filters should keep that unit running for a long time. When the time comes to replace it however, don't get another Coralife. There are many places where you can get a much better unit that doesn't have all those threaded compression fittings.

The white fuzz on the driftwood is a fungus; I see this from time to time when adding new wood to the tank. It is harmless; my BN's & SAEs in the past have not touched the stuff, but it will go away on its own after a week or two.

True silica sand should not add KH to the water as it is very inert. Are you using an aragonite sand, crushed coral, or some other marine based substrate? 

You should invest in a simple TDS pen from ebay; I bought several of them for about $12 each. You can pick up a TDS meter for your RO unit pretty inexpensively as well.


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## Fishthusiast (Jul 18, 2013)

WallaceGrover said:


> You could try to use peat to lower the pH, but I suppose that wouldn't help you with the kH and GH problems. My tap water is something like 8+ pH right out of the tap with kH in the teens, so I can definitely understand your problem. I wouldn't be so sure it was the sand causing a kH rise.
> 
> On the algae, no amount of sterilization is going to keep it down if the conditions are conductive to growing it. Even if you could sterilize the wood perfectly the algae could come in via any plant, or even through the air on spores. Maybe your light is too high or you have nitrogen or phosphate that plants aren't competing with the algae for...


I'm not having a problem achieving the right pH with the RO/tap mix. By mixing the two, I can get it right where I want. The sand is definitely raising the pH, because I have two test containers: one with RO water and another with RO water and sand. The container with just the RO water is reading a pH of a 6 or less and the container with the RO and the sand is now reading almost a 7, with 1 degree Kh, after 5 days of sitting out. So yeah, definitely buffering the water somewhat. I also did the same thing with Onyx sand, and found out that stuff buffers the water a lot.

The algae isn't 'new' though; it is probably the brush algae from years ago. Have you tried bleaching driftwood before? Is it safe?


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## Fishthusiast (Jul 18, 2013)

MissileBear said:


> Pure water should have a pH of 7 with no KH or GH. You would be hard pressed to get this without using DI resin; for our purposes it really isn't needed as we need some KH and GH. Your RO unit should be fine for what you need to do even at it's current age. Membranes for that unit are cheap; assuming that you don't have a lot of hard water buildup inside the unit, replacing the membrane & filters should keep that unit running for a long time. When the time comes to replace it however, don't get another Coralife. There are many places where you can get a much better unit that doesn't have all those threaded compression fittings.
> 
> The white fuzz on the driftwood is a fungus; I see this from time to time when adding new wood to the tank. It is harmless; my BN's & SAEs in the past have not touched the stuff, but it will go away on its own after a week or two.
> 
> ...


The thought crossed my mind that it could be a type of fungus, either that or remnants of the brush algae. However, I did boil the driftwood recently, so I would have thought it would have killed the brush algae. The boiling got rid of the fuzz, but when I put it back in the tank the fuzz reappeared after a week and is getting worse. Have you ever bleached driftwood? I'm just curious as a general question. I am also wondering if the 'fuzz' would go away if I had fish in the tank, which right now, I do not, obviously. I'm also wondering if more light would help, if it is indeed a fungus.

I am not sure of the 'type' of sand this is, but it isn't crushed coral, that's for sure. My pH would be MUCH higher. It is a black sand and very fine. I no longer have the bag for the sand, so it is impossible to determine what it is, at least form my end. I thought the same thing though, that it was inert, until I dropped a handful into a container of RO and let it sit in it for a week. Now it is showing a pH of almost a 7 with a Kh of 1.

In terms of the RO and pH and all that other fun sh*t...

Ok, from my understanding, an RO unit is supposed to remove 98-99% of all hardness from your water, correct? If that is the case, then it is removing nearly all the Kh and Gh from the tap water. Therefore, how could the RO have any pH if there is no Kh?

Ever since I have owned the RO unit--from day one--the pH has tested in the yellow on my card (6.0) and there has never been any Kh or Gh that has registered on my test kit. Wouldn't this mean my RO unit is working as it should?

How would the RO unit have a pH of a 7 if there is no Kh to put it there?

The RO unit is a 4 stage, and I am pretty sure the third chamber is a DI cartridge. Also, I'm not concerned about the unit itself, only the fact that I haven't replaced the membrane or any of the other cartridges. THAT is why I was wondering if it was working properly.


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## Fishthusiast (Jul 18, 2013)

Thread Bump!

I know I am being annoying, but I am really trying to get to the bottom of some issues here. Any feedback is appreciated.


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## Yo-han (Oct 15, 2010)

Fishthusiast said:


> The thought crossed my mind that it could be a type of fungus, either that or remnants of the brush algae. However, I did boil the driftwood recently, so I would have thought it would have killed the brush algae. The boiling got rid of the fuzz, but when I put it back in the tank the fuzz reappeared after a week and is getting worse. Have you ever bleached driftwood? I'm just curious as a general question. I am also wondering if the 'fuzz' would go away if I had fish in the tank, which right now, I do not, obviously. I'm also wondering if more light would help, if it is indeed a fungus.


This comes from sugars leaching out of the wood. By boiling it you damaged a lot of wood and made it soft. No it's rotting faster because of the boiling and the fungus/bacteria use it. You can suck them away with every water change. They are not harmfull and will be there for weeks/months depending on how much boiling you did and the type of wood.



Fishthusiast said:


> I am not sure of the 'type' of sand this is, but it isn't crushed coral, that's for sure. My pH would be MUCH higher. It is a black sand and very fine. I no longer have the bag for the sand, so it is impossible to determine what it is, at least form my end. I thought the same thing though, that it was inert, until I dropped a handful into a container of RO and let it sit in it for a week. Now it is showing a pH of almost a 7 with a Kh of 1.
> 
> In terms of the RO and pH and all that other fun sh*t...


Don't bother about pH, fish don't care, plants only a little so only bacteria care about pH. Fish care about KH/TDS the things which influence pH, they don't carry pH meters and most fish are able to adapt to pH 4-9 as long as the KH is in a normal range for that type of fish. A pH meter to test a RO unit is like testing apples for pH whether they will taste good. It will tell you something but nothing about sugar content, flavor etc. of the apple. So stop bothering about it!



Fishthusiast said:


> Ok, from my understanding, an RO unit is supposed to remove 98-99% of all hardness from your water, correct? If that is the case, then it is removing nearly all the Kh and Gh from the tap water. Therefore, how could the RO have any pH if there is no Kh?
> 
> Ever since I have owned the RO unit--from day one--the pH has tested in the yellow on my card (6.0) and there has never been any Kh or Gh that has registered on my test kit. Wouldn't this mean my RO unit is working as it should?
> 
> ...


Start reading what pH is. You bother but you've absolutely no clue how it works! That sounds harsh but I think it is true. Water with 0 KH is always pH7. I think you assume your water should have a pH of 0-1 with KH=0 but thats not true. Pure water always has a pH of 7. If it is anything else something else is in the water. This might be an acid like CO2, or whatever but it should be 7. If I breath through a straw, I can easily drop the pH to 5. Did it change anything (fishwise) to the water? No. So buy a TDS meter or decent KH testkit that can measure up to 0.1 KH, otherwise you make yourself crazy and find yourself bumping this thread all they while all answers are already on wikipedia. The best article to read: http://www.americanaquariumproducts.com/aquariumkh.html#overview This might be though info but read it. If you don't get it, read it again. If you still don't get certain part, ask them here and we'll help you But read the basics first. I can explain them all day long, but someone else took the time before me.http://en.wikipedia.org/wiki/PH


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## Fishthusiast (Jul 18, 2013)

Yohan,

I appreciate all your advice. Just bear with me. For every single thing that I know or learn, it is usually deconstructed by a more advanced piece of knowledge that erases the knowledge I already thought I had. I will indeed read the article. In fact, I already started.

Check out the thumbnail of the white substance, which I assume is the fungus (I didn't know fungus could grow IN the actual water) or it is brush algae. If you can confirm that it is indeed fungus from the photo, that would be a big help. The pics may be opening sideways. You should be able to see the white fuzz.


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## Yo-han (Oct 15, 2010)

Looks more mine fungus to me indeed. Nothing to worry about, mine covered a 9 squared inch area of wood I saw off. Otocinclus even nibbled on it from time to time


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## Fishthusiast (Jul 18, 2013)

Yo-han said:


> Looks more mine fungus to me indeed. Nothing to worry about, mine covered a 9 squared inch area of wood I saw off. Otocinclus even nibbled on it from time to time


Yeah, that seems to be the general consensus. Do you know if it is from the water or the wood itself? And do you think it's best to keep my light on or off? I'm also wondering if I should replace the water, or just leave it be. I know everyone says it'll go away, but it sure doesn't seem like it. I am also trying to expedite that process any way I can. Keep in mind I have no fish in this tank and can manipulate things at will.

I also scrubbed it off again and sure enough, it is already coming back.

A better photo is there in the thumbnail. The black stuff is just my sand.


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## Yo-han (Oct 15, 2010)

I believe it is from sugars leaching out of the wood. This will happen in any water. I always scrubbed it off with a toothbruss and sucked it up till one day (about 2 months if I recall it right) it didn't came back


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## Fishthusiast (Jul 18, 2013)

Yo-han said:


> I believe it is from sugars leaching out of the wood. This will happen in any water. I always scrubbed it off with a toothbruss and sucked it up till one day (about 2 months if I recall it right) it didn't came back


Yeah but you probably had your tank up and running with fish in it. I am wondering if having a more normal environment like that would make it go away, as opposed to what I have going now, which is just the wood, water and sand. I just don't want to set my wood up again in my pretty ornamentation just to have to perpetually scrub it. I just end up moving everything around in that type of process.

I have also been reading the link you sent. I have questions. Do you mind if I pm you at some point so I don't keep bumping the thread?


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