RO Questions

[4abettalife]

I've just purchased the Aquatic Life RO Buddie to help me deal with my undesirable water parameters. It's now hooked up and has pumped out it's first few gallons and I already have a lot of questions and concerns.

1) The water I'm putting into the RO unit is over a pH of 8. pH 6.4 seems to be coming out. What is the normal difference between the pH input and output.

2) I have an DI unit arriving. My understanding is that this will take the TDS to 0 (right now it's 9, so that doesn't concern me too much!) but will it reduce pH as well?

3) My unit says it functions best with intake water being 77F. Any idea how to ensure the water going in is 77? I thought using water that has gone through the hot water tank was bad, but given that I live in Canada the straight cold is around 55F or lower.

4) When they say the membrane must stay wet, how do I do that? I only plan on using this a couple times a week. Does it dry out in-between?

5) What is the best method of storing this water? I've heard that water stored in bins or tanks for too long can have bacteria issues. Is aeration recommended? How can I avoid issues with the stored water?

Thanks so much!

 

[Coyne]

I've just purchased the Aquatic Life RO Buddie to help me deal with my undesirable water parameters. It's now hooked up and has pumped out it's first few gallons and I already have a lot of questions and concerns.



1) The water I'm putting into the RO unit is over a pH of 8. pH 6.4 seems to be coming out. What is the normal difference between the pH input and output.



2) I have an DI unit arriving. My understanding is that this will take the TDS to 0 (right now it's 9, so that doesn't concern me too much!) but will it reduce pH as well?



3) My unit says it functions best with intake water being 77F. Any idea how to ensure the water going in is 77? I thought using water that has gone through the hot water tank was bad, but given that I live in Canada the straight cold is around 55F or lower.



4) When they say the membrane must stay wet, how do I do that? I only plan on using this a couple times a week. Does it dry out in-between?



5) What is the best method of storing this water? I've heard that water stored in bins or tanks for too long can have bacteria issues. Is aeration recommended? How can I avoid issues with the stored water?



Thanks so much!

I'm new to RODI water myself, but here's what I've gleaned so far.

1) the water coming out should have a pH of 7, or neutral. However, after sitting out for a bit, the CO2 in the air will mix in and cause it to drop to 5.5 (I think).

2) I do not believe the DI filter will impact the pH that much, but I've never tested it before and after the DI.

3) the colder the water, the slower you will produce RODI water and the more waste water you'll produce.

4) I leave the unit full in between uses.

5) You should be using a container that is "food safe" so that it won't leech any thing bad into the water.
I keep an air stone bubbling, though I can't say for sure if it's needed. I also keep a heater in there, but only plug it in the day before I plan on using the water.


Sent from my iPhone using Aquarium Advice

 

[J.Mcpeak]

Mainly question 1&4, Coyne basically nailed it!

1) (and a little bit of 2)
There is no normal difference, everybody has a different input source.
Normally after DI it is a neutral reading. (For a short time only, until equilibrium)
The resin will exchange ions in the water until a neutral balance is reached.
It's called de-ionising resin but really it should be called ion exchange.
I haven't tested the pH of the RO before DI. There is no need.
4)
Fit a ball valve on the inlets/outlets, then close these.
Leave membrane in flush mode and slowly increase pressure on the inlet until it is 40psi or more. (40psi is the minimum operating pressure for your membrane)
This ensures it is wet across the membrane not just on one side.

(Isolate before DI bed, prevents equilibrium prematurely exhausting resin)

With frequent use this is not necessary as the membrane doesn't have time to dry.

(Coyne)
Glad the new unit is working for you.

Everything you say I think is correct.

It's considered safer to aerate the water as RO water is oxygen poor.
(By the time it's poured from vessel to bucket to tank, that's enough)

Aeration or water movement prevents stagnation.
If the water is stored for a day it will be ok, a week, I'd aerate.

Any water that has been de chlorinated will have a greater bacterial potential.

 

[Coyne]

Finding the right storage container was by far the biggest problem for me. I eventually had a lucky break and was able to get exactly what I wanted without having to spend a ridiculous amount. Your results may vary.


Sent from my iPhone using Aquarium Advice

 

[4abettalife]

Thanks everyone! This has been a little more involved than I expected. I thought I'd just be able to screw the RO unit into my tap and go. I guess there is some sort of pressure reading valve I need to put on first? Once that's done, I'm still not sure how to monitor and create the correct temperature going in....

I'll shop for water reservoirs today. Will the typical rubber maid suffice? Or do they often leak or leach? Thanks!


Sent from my iPhone using Aquarium Advice

 

[Coyne]

I wouldn't sweat the temperature. Like I said, it just slows things down. If you can figure something out, great... but don't let it stop you if you can't.
A pressure gauge isn't a bad idea. I think the optimal pressure is 60 or 70 psi. If its lower, then it just slows down production like colder water does. My pressure is 40 psi with a current temp of 55F and Im producing.
I put the gauge at the end of the line. As the filters become less efficient, I should see a drop in pressure... so its a good indicator for when its time to replace stuff.

Ive heard of other people on the forum using large Rubbermaid containers/trashcans to store their water. Its probably fine. It was going to be my backup plan if I wasn't able to find the container that I ended up with.

 

[J.Mcpeak]

The temp actually makes a very large difference to production.
It isn't worth trying to heat the water first, just be patient.
The units need a cold water supply so that should really say DO NOT USE HOT WATER

Temperature correction factor. (@ nominal operating pressure 60psi)
Temperature
@25/77 gives 1(cf) (100GPD is 100gpd produced)
@15/59 gives 1.47 (100GPD is 68.02gpd produced)
@9/48 gives 2 (100GPD is 50gpd produced)
@5/41 gives 2.58. (100GPD is 38.75gpd produced)
Pressure is also very important, these figures are guides for 60psi
+/- any PSI will affect production speed accordingly.

GPD/cf=US GPD
So you can get a rough idea for a range of temps for your unit.

Using a normally configured RO unit, the pressure gauge should go before the membrane and after the CCB.
To detect filter efficiency a second gauge needs to be installed before the pre filter. The reason is, a single gauge is controlled by input valve, this fluctuates with temperature. Also if another water source is used (bath/pan/tap) this reduces input pressure at the unit.

Keep track of dates and production, the most critical aspect is volume throughput on the CCB, they are rated normally at 6months or x amount. This figure is the effective ability of the CCB to remove chlorine. Chlorine will destroy your membrane instantly.
Replace pre filter/CCB as appropriate. This will prolong the life of the membrane. It should give 4-6 years of use.
You are better off playing it safe here.

Coyne, at 40psi you are only just producing water. Are you on the main fed or the storage tank?
The reason I'm asking, if you lose just 1psi you stop producing RO water. Waste water will continue to flow. Factor in temp correction and in the dark of winter production will be painfully slow for you.

(Pressure gauge simply connects in with a T, kits normally contain all pieces)

 

[4abettalife]

Oh boy. This is pretty complicated! So, my RO unit came with 1/4 tubing. Does this mean the pressure gauges will fit in the 1/4 tubing? Or is this something that goes on a garden hose size and then the 1/4 is the next step down?

Unfortunately, in my attempt to get 77 degree temperatures I know the RO unit was taking in water above 100 degrees for around 20 minutes. The package states not to exceed 100 degrees because of the membrane. Could I have wrecked it?

So I guess if I need to use some water from the hot water tank to achieve something close to 77 this is fine? The RO unit will just remove any impurities that come from the tank. I feel I need to do whatever I can to make the process efficient because currently the filtered water is a very minimal trickle. I'd be pretty shocked if I was actually getting my 40 gpd.

Thank you for all of the technical data. It definitely fills in some blanks that I've had! It seems buying and installing the base RO unit is not the end of the RO setup journey for me!


Sent from my iPhone using Aquarium Advice

 

[J.Mcpeak]

Cheers, no problem, I'm glad to help, otherwise I wouldn't reply!
The gauge kits are made for Ro units and will have 1/4 fittings.

Don't fuss over the temp. Use the cold water feed. It is a trickle at the best of times!
If you are expecting a mains flow squirt from the end of your unit, get prepared to be severely disappointed!

If the TDS goes up on the production then the membrane has had it.
(Test before the DI bed)

https://www.flickr.com/photos/92891884@N04/13327145555/in/set-72157632686866609/
Under this picture has some info about production/efficiency.
Adjacent pictures of the unit have further info in places.

FORMULA= (TDS Input - TDS output)/output X 100.

(Eg. tap water reads 450ppm TDS, and Reverse Osmosis filtered water reads 15ppm.
450-15=435
435/450=.966
.966*100=96.6
So, my reverse osmosis is running at 96.6% TDS reduction.)


I'm not sure how you would easily get a dual feed on hot/cold, is it a tap fitting?
Mine is hard wired to a cold feed.
Also it's quite inefficient to heat water then put it to waste. I'm not sure overall efficiency is maintained? Gas/electric +water?
You might get a better production speed but this would be countered by energy costs, possibly even a negative impact.
I haven't looked into it much though, I just accept that it runs slower in the winter.

If it's under the spec I'd say it's fine to use.
Do you have a TDS meter?

No this is just the beginning for you!
See where I landed with RO units!

https://www.flickr.com/photos/92891884@N04/10156612035/
Last October

https://www.flickr.com/photos/92891884@N04/14510563174/
June 2014.

 

[4abettalife]

Yes, I do have a TDS meter. I'm really enjoying it. What an easy to use, helpful little tool!

Thank you for the formula to figure out my efficiency. That will be very helpful in finding out if my RO unit is doing as well as it should be. It seemed to be going a little better tonight. My far more technical husband was able to get some of the leaks stopped and that actually really helped with the output.

It was great to see your setup! That's some great counter and sink space! And your water storage is very impressive. That's fantastic! Make me rethink my setup….

If I may ask another question. How stable is RO water once remineralized or mixed with a bit of tap water. I'm hoping to end up with parameters around 6.5, TDS of 150, GH3-4 and KH1. These are my goals. If I can achieve them with my reminerilizing product, do they tend to stay this way until the next water change? Or do the parameters change around? pH switch? TDS rise unexpectedly? The water will be heated around 72F and aerated. I'm just curious if daily testing and parameter tweaking will be necessary to successfully use RO in my tanks. Thanks!

 

[J.Mcpeak]

Good, the TDS meter will be your most used tool bested only by a bucket!
Gives a good quick reference on your tank state too!

Don't worry about those formulas, they are readily available, I keep them because I need them, the temperature data came with my unit, the efficiency formula is online.
No skills, no clever stuff from me!

Thanks for looking at my pics! That's my pride and joy, it's all a bit silly but that's where I ended up! (Be careful, it could happen to you!)
I did the "under the kitchen sink" thing for a few years when the first fish room happened, since I needed a new building (the big tank didn't fit through the new door when I moved) I was "forced" into building a shed. New build or quit fish, fish win.
I ironed out almost all of the things that annoyed me about the old set up when I designed this one. It's almost perfect!

Why do you want those numbers exactly?
I used RO cut with tap for years, until the start of this year. 6-7years maybe? Maybe more?
What else will be in the water to get the TDS up? You'll get a lower reading I would think. GH/Kh 3-4 each approx is about 115-126 approx depending on mineral source. (Instrument calibration and temperature variables also effect reading)

Why do you want 6.5ph? You must already know which fish you want.
Control pH by co2, http://www.aquariumadvice.com/forums/f12/unstable-ph-324938.html

Kh 1 is not a safe number, why must it be Kh 1.

TDS rises with (mainly) it's evaporation in a tank. Lots of other factors effect the TDS reading in a tank compared to (new/clean/prepared) water.
RO water rises too. (Leave some out for a day or so, the reading goes up)

If you are fairly new to this whole fish thing, test often, take notes, keep a diary or similar. These notes will form the backbone of your knowledge. Read them, you will see the patterns.

If you're mixing tap/RO you can only equally divide the mineral content of the source water. If you need to adjust an individual set, a suitable powder would be needed.
Perfectly safe for most things, depends on the quality of the source though.

 

[4abettalife]

That's fantastic you were able to build a specific fish area specific to your needs. We have just moved all of my tanks onto heavy duty shelving in one room. Even though there is no sink or counter in there, I can't believe the time I'm saving! An efficient setup like yours must be incredible.

I originally wanted to purchase the RO unit to alter the water for my Betta breeding. I've been able to get some pairs to spawn and have successfully raised the fry, but our water parameters are so terrible out of the tap, getting the fish in the mood to spawn and actually follow through with it is really difficult. I was hoping that cutting the water with RO and taking it to a range closer to their natural one would assist with this.

The parameters I described to you are for the freshwater shrimp I have arriving soon. I think I was a little foolish trying to learn how to manage my RO system and parameter "creation" at the same time as having these shrimp arrive. Particularly when they are something I haven't kept before. I'm really trying to learn all of this to manage them properly as the RO isn't going to make it or break it for the Bettas. Apparently the Caradina's need KH of 1-2, requiring the addition of a buffering substrate to keep it that low.

I did buy Seachum GHup, so I think I can get the levels low and then use this just to elevate the GH, without affecting the KH. I really don't know what this will do to the TDS until I try it. It would sure be wonderful to have low pH, KH, GH water right out of the tap!

Keeping a journal is a good idea. I'm sure I'll be forgetting things and having to redo, redo, redo! I've started writing parameters on the tanks with a dry erase pen so I can see if they are changing and try to figure out why...

 

[J.Mcpeak]

It is happening to you! ArrrrrghWOOOoooooooo!

I did the one room thing (4tanks2day link) yes it is much much better than a few areas, once I had tanks in the living room the hallway then another snuck it's way into the bedroom, then, hmm yes, time for the fish room. I had a shelf and little corners I used, that worked well enough for years, when this one "had to be built" this time I thought, 6ft worktop, sink, water, Nice. Iron out the kinks.
Now I'm thinking cut a few feet from the worktop and stick 2 tanks in the hole on the end! The only thing I never allowed for was the climate of the room, that was an afterthought, blindly thought the water volume would stabilise the room temp, maybe in a house, didn't work outside!
Sooooo Lucky me, from a certain angle yes. If you like fish this is a little slice of heaven.
The room (technically it's a DIY shed) is the next step up from what you have and really it's better, I'd recommend a nearby sink to anybody. Being two steps away for all tanks is a god send! The reservoir is by far the best new addition though, do your time with those containers first otherwise you won't feel the benefit

Yes the unit probably will help. I got mine to help with water for the L030 plec, that's how it happened, that fish really wasn't happy in my tap water. The unit fixed it and it allowed me access to other fish, well, any fish if I could fit a tank in for it! So I had a load of different fish for a while, I hope that it solves the issue for you. Breeding is very rewarding!

Can't really help you with shrimp, never kept any but tetra prefer the softer acid/neutral side of things normally, Kh 2 is markedly better/more stable and just as good as one. They'll be fine in 3-4 Kh I would think. My tetras have been in 3-6 on both GH/Kh for ever. (Not cardinals though) Unless you have some ultra special fish (I can think of true soft plecs, the blue phantom L128, that thing liked next to pure water real soft/ultra low) but I'm not that educated on many other real softs. I like sucker mouths. Any change of GH/Kh will see the TDS rise and fall as appropriate.

Good water to start with would be good! Where's the fun in that though? I still don't think that water is good for marines so it still isn't a perfect start, I may be wrong on that but it wouldn't be as pure. I guess if you don't want salt it doesn't really matter!
From here you can go anywhere, no worries. I knew I'd get salt one day so wasn't too fussed with the plec needing it, still no salt! I'm sure mine has worked wonders, I mean you can see the difference if your water is really poor. An actually clear glass of water! In use you'll see a difference too! Almost instantly with some fish, they colour up nice.

I had a diary on my first tank, then I went without for a year or so, then I made a mess of things so I got a diary again, I think I have almost all of my diaries, I did have loads of paperwork on fish, not quite a cabinet but not far from it. One tank is not so bad if you have decent memory, multi tanks is where I got caught out. Once I started logging my efforts I could see exactly why things went wrong. Adjusted for it. Sorted.

Really for the initial experiments a diary of some sort is a must have, it's a tool.
If anything happens log it, then decide what info you deem necessary to keep. I wrote down everything first of all. I've relaxed a bit now but all tank data is logged, every action. Filter records and water changes that type of thing. Dates for food purchase(logged my bulk buys to tune order, that took about3 years to get right @1 order per year), RO data etc. I started with a notebook and I ended up using an annual diary. Now I get a diary at christmas like regular folks get socks!