RO/DI help

[Brown Water]

I am thinking of getting a ro/di unit. My water is coming out of my tap at moderate hardness, high kh, 7.5ph. I regularly use acid buffer to try and drop the ph in my tanks, but it seems to only settle out at about 7.2. I can get it to drop to about 6.7-6.8 for about 12 hours but then it shoots back up to 7.2... The guys at the lfs say to just keep adding acid buffer and it will come down eventually, but in the past when this has been tried it quickly crashes down to 4.0-4.5 and kills everything in the tank.

I am looking at a ro/di unit to bring down the ph,gh,kh, and tds of the tap water.

I guess I have a lot of questions about it, that no one can seem to put into lamens terms for a ro/di newbie.
Everyone talks about the buffering capabilities of the pure water... No clue what they are talking about.
Will pure ro/di be ok to start trying to track down and keep soft water wild apistos, wild angels (altums and scalare) discus and so on? Will I have to do anything to the treated pure water besides add the electrolytes or whatever they want back in to the water? Safe for plants? Mostly amazon swords and java moss? Everyone talks about adding tap water back into the ro water... Why? Won't that just defeat the purpose of the ro water?

Guess I'm really looking for some guideance and help to get it up and going. And make sure it's the right route for me.

I am looking at a 50gpd unit and will have to make about 100 gal a week for water changes, that's not including what I would assume the initial full drain of the tanks and refill with ro/di water I would have to do to get them started.

 

[dw1305]

Hi all,

The guys at the lfs say to just keep adding acid buffer and it will come down eventually, but in the past when this has been tried it quickly crashes down to 4.0-4.5 and kills everything in the tank.

Go to a different LFS.

Will pure ro/di be ok to start trying to track down and keep soft water wild apistos, wild angels (altums and scalare) discus and so on? Will I have to do anything to the treated pure water besides add the electrolytes or whatever they want back in to the water? Safe for plants? Mostly amazon swords and java moss? Everyone talks about adding tap water back into the ro water... Why? Won't that just defeat the purpose of the ro water?

You don't have to add tap water back in, it is just that for a lot of people their tap water is hard, but otherwise of reasonable quality. You can use a mix of approx 90:10 RO:tap to add back some dKH and dGH. Have a look at "James's Planted Tank" <http://www.theplantedtank.co.uk/RO.htm>, and that will cover re-mineralsing your water and feeding your plants <http://www.theplantedtank.co.uk/calculator.htm>.

Alternatively you could also use the "Duckweed Index" as a plant feeding method. Details in this post <http://www.apistogramma.com/forum/index.php?threads/daphnia.12707/>.

cheers Darrel

 

[Jacco]

Hi Brown Water,

Darrel already gave you some guidence with the links. I can add my personal experience.

First of all, how large is your tank? The larger the tank, the more effort it takes to change waterchemistry, incl pH. I have a 700 liter tank and it took me forever (4 weeks) to change the pH. My pH of tap water is 7.5 and GH is 12. (GH is a measure for Calcium in your water, and in short is your buffer, as long as GH is high your pH will have trouble going down, but you'll probably read that in the links)Anyway, my tank runs fully on RO water. The RO water has pH 7.5 and GH 0. (so the buffer has gone)

In order to lower my pH I filter my water through peat (humopond from JBL). How much you need depends on the size of your tank. I use about 5-10 liters of peat in my filter (peat outside your filter won't do much, water really needs to flow thourgh!). My pH is stable at 6.2. The peat now acts as a buffer keeping my pH stable. Watercolor is light yellow.

RO water doesn't contain nutrients, and my plants use more than my fish can "produce". So I add some KNO3 every week and some micro elements like Fe, Mn etc. I have cabomba, mosses, and echinodorus and some floating plants all still pretty happy and a few algea (reasonably unhappy). The fish seem pretty happy (some paracheirodon simulans fry is swimming.)

When u use peat, don't forget to thoroughly rinse it first and leave it in water for a day or so before using it. I made the mistake once using it straight in my aquarium and it used a lot of oxygen, making my fish swim at the surface looking for air. (extra watermovement and an airpump saved them)

Hope this helps you,

 

[Brown Water]

Well here it is almost a moth later and still no ro/di or ro system. Everyone seems to have their own explanation for what both systems do and what I need... One person says just ro filter will work for me, someone else says ro with a water softener prefilter (thought ro was suppose to make the water soft) one guy today told me that a ro filter won't even drop my ph! Idk what's true, false or what I need and don't need... Guess my dreams for wild apistos, angels and discus shall be put on the back burner till I move somewhere with cleaner water.

 

[Jacco]

Hi,
here some facts:
ro water is soft.
ro water is normally round pH7 -> so if you want a lower pH you have to add acid (peat)
In ro water there are virualy no solvents like nutrients etc. so you might need to add some (depending on how much you feed your fish) if you have specific plant growth wishes...
hope this clears your waters a little bit.

 

[Mike Wise]

It would also help if we knew the actual hardness values (dGH, dKH) of your tap water. "moderate hardness, high kh" are a bit general. Without knowing how hard "moderate" is and high "high kh" is we really can't know whether or not special processes (pre-softening, back-flushing) are needed with your tap water.

 

[jaafaman]

,,, Everyone talks about the buffering capabilities of the pure water... No clue what they are talking about.
Will pure ro/di be ok to start trying to track down and keep soft water wild apistos, wild angels (altums and scalare) discus and so on? Will I have to do anything to the treated pure water besides add the electrolytes or whatever they want back in to the water? Safe for plants? Mostly amazon swords and java moss? Everyone talks about adding tap water back into the ro water... Why? Won't that just defeat the purpose of the ro water...

I would venture to guess that no one will be able to give you anything useful until you invest the time to understand what it is they're doing and why. Until then, I would anticipate a lot of red herrings and false starts because you have no way to temper all of the advice you're trying to assimilate since there's no real reference point from which to start...

 

[Ganz]

Don't let this get too complex. Remember that some people posting have elaborate plant set ups with CO2 injection and mega gigawatt lights and other people are fish breeders. Their objectives are different from yours.
In your case, your setting up a community tank. It's easy to get lost in the chemical jargon. A buffer is like floor or bottom. The fish that you want to keep, they don't like a bottom. That last few Ph points that your worried about, put some wood in your tank, a bag peat in your filter, don't put any more chemicals in your water, sit back and wait for the fish and bacteria to do the magic. Keep changing the water with RO
and after a while (months) that buffer floor just falls out. It doesn't happen overnight. But, you must be certain that there is nothing else in that tank that can buffer your water like: certain rocks or shells or the substrate itself. The plants that your using will live on the waste from the fish. In my tanks I do supplement with Root tabs for iron. The swords turn transparent without it.

 

[Brown Water]

As an update. I ended up getting a ro/di a few months ago, thing works awesome. PH coming out is about 6.5-6.8. End up getting the TDS up to 100-120ish before my water changes. Still playing with it, rams and panduro love it, cacatuoides have yet to spawn for me tho. Haven't figured out what is off enough for them to hate it so much. My shrimp make me scratch my head quite a bit, try and keep them at about 200-250 TDS. Still lose a few some days.